Lock Miter issues...

[Bryan Mills]

So i've read all about these joints and the bits used to create them and have taken my time in setup and testing, but I'm having a problem that i don't quite understand.

The bit height is correct, of this I am sure, as you can see in the photo.

http://i2.photobucket.com/albums/y36/Ptownkid/100_3306_zpsfde49ae0.jpg

however the issue is with the second piece that gets cut...there's a small but unacceptable flat area on the edge of the piece cut vertically.

http://i2.photobucket.com/albums/y36/Ptownkid/100_3307_zpsf6857313.jpg

The only way to get rid of this, is by adjusting the fence back further. Since the edge of the other piece is already being cut right to a sharp edge, moving the fence back would mean that the cutter would now narrow the first boards width by the same amount as the flat you can see, and it would mean that the edge of that first board would no longer ride on the face of the fence making good result impossible.

Is there something I'm missing or is it simply possible that the bit is too small for 3/4" stock even though the manufacturer says it is possible...

[Bill Huber]

Your bit height is off, this link is from Whiteside and it shows you just what you need to do. If you notice the part on the right in the last picture is not cut correctly, it should come to a point on the edge and not have a flat on it at the top edge.

http://www.whitesiderouterbits.com/LockMiterInstructions.pdf

[Mel Fulks]

There are a number of treatises on this subject. Here's mine .I like to run vertical pieces first ,intentionally leaving a little smaller flat spot toward face side than the inside . I do not cut to a sharp point, I leave a tiny flat. What that does is help stop tear out ,and means that your cutter height adj for horizontal cut will be zero or UP. Much better than not knowing which way to go. It also means your material does not need to be over size. If you are making a 5 inch box get material exactly 5 inches, when assembled it will be slightly oversize for sanding and the tiny notch at corners will disappear.You will find horizontal cut will need some fence adj.

[Bryan Mills]

How can the bit height be off? Look at the first picture...if I raise or lower the bit at all, the two pieces will no longer line up. Does that not matter?

[ken masoumi]

Is it possible that the two pieces have slightly different thickness?

[Bryan Mills]

No, i should have mentioned that I supposed. They are the same thickness...

[Mel Fulks]

I've seen some real capable guys go berserk trying to use those things . Save some samples and put your own notes on them. The method I posted requires that you run ALL the vertical pieces first .THEN CHANGE to do horizontal pcs. I have not seen the way shown in link work without moving fence when going back and forth between vertical and horizontal,but I don't see that mentioned. I do agree that in their set up you don't have to move cutter head . But that way ,tear out can be bad.

[Bryan Mills]

From everything i have read, you should not have to change anything to cut the pieces once the setup is right. I'd like to try and accomplish it that way if I can. The Whiteside instructions don't really tell you much...

I'm not using an Infinity cutter...but here's their instructions

http://www.youtube.com/watch?feature=player_embedded&v=v-_bGkR2SKM

[Mel Fulks]

Just watched it. The camera is cut off before he runs the second piece ,and he does mention that the fence might have to be moved. Poor instructions. He should have had the 2 fence positions marked with tape,or pencil; left the camera running and showed the change. I've also seen guys buy those cutters and NEVER get them to work ,again poor instructions.

[Bryan Mills]

I can see there may be the need for a small adjustment sometimes, but I literally can't find ANY info on the internet that says this is needed once you have the setup right. Not to mention that we're not talking about a small flat that requires a small adjustment, it's large.

This can't be normal...

[George Bokros]

I believe the reason the two pieces in the first picture line up is because they are both cut flat on the table, am I correct? If so they will always line up. I have never used that bit but I believe I am correct, if not please tell me so.

Thanks

George

[Bryan Mills]

Yes George you are correct, they are both cut flat on the table, but one is upside down when they are mated. That means that if the bit height is not perfectly centered to the work piece thickness they will NOT line up.

[Phil Erup]

Yes George you are correct, they are both cut flat on the table, but one is upside down when they are mated. That means that if the bit height is not perfectly centered to the work piece thickness they will NOT line up.

If you do the same test on two vertical pieces with proper alignment, you should then assure matching centered sides.

[Mel Fulks]

I thought I was on the Internet ! This thing doesn't look like an etch a sketch to me. Much of what you are reading is coming from the same incorrect sources. I might be out voted ,but I am not wrong! I have used those cutters ,usually on shapers , for decades and would like to help you . The manufacturer just wanted you to buy the cutter,THEY are happy. How far you have to move the fence is dependent on how thick the material is. If you look at your own pictures you will see that the fence must be moved. Once when I was asked by a contractor to make some newel posts he gave me a drawing showing butt joints.I showed him the lock mitre cutter and told him I would mitre them. He said " every shop I deal with has one of those cutters, they don't work". Changed his mind. As I said before many never get them to work.

[Jim Kirkpatrick]

Yes George you are correct, they are both cut flat on the table, but one is upside down when they are mated. That means that if the bit height is not perfectly centered to the work piece thickness they will NOT line up.

The bit height is fine. Where you are going wrong is the vertical pieces is not held tight against the fence, or table. Review your technique and make sure it is both flat against the fence and flat against the table. I wrote a tutorial about it a while back here:
http://www.sawmillcreek.org/showthread.php?132180-Lock-Mitered-Drawer-Tutorial&highlight=lock+miter

[Mel Fulks]

Let the record show that Jim also mentions moving the fence.

[Alan Bienlein]

So i've read all about these joints and the bits used to create them and have takien my time in setup and testing, but I'm having a problem that i don't quite understand.

The bit height is correct, of this I am sure, as you can see in the photo.

http://i2.photobucket.com/albums/y36/Ptownkid/100_3306_zpsfde49ae0.jpg

however the issue is with the second piece that gets cut...there's a small but unacceptable flat area on the edge of the piece cut vertically.

http://i2.photobucket.com/albums/y36/Ptownkid/100_3307_zpsf6857313.jpg

The only way to get rid of this, is by adjusting the fence back further. Since the edge of the other piece is already being cut right to a sharp edge, moving the fence back would mean that the cutter would now narrow the first boards width by the same amount as the flat you can see, and it would mean that the edge of that first board would no longer ride on the face of the fence making good result impossible.

Is there something I'm missing or is it simply possible that the bit is too small for 3/4" stock even though the manufacturer says it is possible...

Go to this thread http://www.sawmillcreek.org/showthread.php?199430-Sommerfeld-tools-easy-set-router-bit-setter and go to post #5 and it will be explained. I have done it his way and the lock miters come out perfect the first time. No practice cuts required!

[Alan Schaffter]

Ok, time again for me to weigh in. As I said in an earlier thread on this topic (here is the link (http://www.sawmillcreek.org/showthread.php?199430-Sommerfeld-tools-easy-set-router-bit-setter)), most, if not all lock miter instructions are poor and many are downright WRONG. Sorry, Bill, but that includes Whiteside's instructions! When my Lock Miter Master set-up jig hits the streets in a few months, I'll post the complete instructions here on how a lock miter should be set.

The biggest problem with most instructions is that they attempt to use the center of the bit profile, but few if any (including Whiteside) correctly identify it!!! As soon as I find it, Ill post another drawing showing where the center is located, but look at the one below and follow my description, the HORIZONTAL AND VERTICAL center of a lock miter profile is at the intersection of the 45° cutting edge and the common male/female profile edge. That is the TRUE center and only that point!!! That point should be aligned with the centerline of the stock (equal thickness stock) when the stock is cut in the horizontal AND vertical positions. (The profile center and board centerline can also be used to make offset miters and miters in boards of unequal thickness but that is for another time/another post)

http://www.ncwoodworker.net/pp/data/2580/Where_is_the_center.jpg

http://www.ncwoodworker.net/pp/data/2580/Here_is_the_center.jpg

http://www.ncwoodworker.net/pp/data/2580/medium/Lock_miter.jpg

It "appears" that Bryan has the bit height set properly, but a lock miter needs both bit height and fence position set properly (for a standard joint), but guess what? The setting for one will affect the setting for the other! Also, the settings for both must be precises- "close" is not good enough! Since his fence is not set properly, it means his bit height is not correct either- or his stock is not the same thickness although in this case it looks like it is.

The joint he cut, which I call the offset joint, is not all that bad. If you cut faceframes with a flat tip you can round-over the corner without cutting into the other board. If the other board (cabinet side) is made from ply, it prevents you from cutting into and exposing interior plies. It is one of the techniques that is easy to do with my set-up jig. Here are drawings and photo of what I mean (imagine the light colored board is plywood):

http://www.ncwoodworker.net/pp/data/2580/medium/Offset.jpg

http://www.ncwoodworker.net/pp/data/2580/medium/IMG_4470.JPG

[Mel Fulks]

Alan,that should be helpful to op. and I appreciate your geometrical approach. We are in complete agreement that the instructions that come with those bits and heads are worthless. The method I have been using eliminates tear out on any kind of wood and consists of simply climb cutting a 3/8 inch round over on all of the inside corners. If a shaper is being used that cut can be run at high feeder speed. And I do not machine edges to sharp point. Never lose so much as a splinter on birch ,maple ,etc. To anyone new, the actual mitre cut must be regular feed. NOT climb cut.

[Bryan Mills]

Now were getting somewhere...

Alan B...where exactly does is explain the process in the thread you linked...he talks about his new jig and the results but I don't see any info about how to do anything...

Alan S, interesting info for sure, and the results look great, but I'm still unclear as to how to get set up to cut these pieces...the only solution I think I've absorbed from this thread is that I need to get the height set, then cut the horizontal pieces, then carefully nudge the fence back until I lose the flat edge. Am i on the right track here? I do like your face frame round over idea, but I need to make some table legs so that's not in the cards. I did try that technique a couple of times and was not really pleased with the results...but maybe I'm too picky.

[Bryan Mills]

Let the record show that Jim also mentions moving the fence.

Yes...but not between cutting horizontal and vertical pieces which is what you were suggesting i needed to do wasn't it? Please don't get me wrong, i appreciate your effort in trying to help me, so please bear with me.

[Joe Scharle]

There's too much confusion about this bit, in my opinion. I set my cutter to meet the center of the side piece (the one that's vertical against the fence) by eye, AND at the same time to cut a clean miter on the part resting upon the table. Bit height gives the centerline requirement and fence position gives the sharp miter cut on the table.
The end piece cut (laying on the table) is met by moving the fence back until the TOP of the board is cut to a sharp miter. No matter what the thicknesses are the joint will be made correctly. No sense in over thinking this thing! Here's a pic of uneven pieces taken for a discussion that Alan and I had on our state site.

255840

[Mel Fulks]

I won't try to speak for Jim . But reading his entire post ,including the text explaining the pictures , I interpreted his fence advice to be same as mine. If I am wrong ,It is misunderstanding .... Not misrepresentation.

[Bryan Mills]

He definitely seems to say that he sets the height, then the fence, then cuts ALL pieces with that setup, but I also could be wrong. Spent some more time trying your technique and I got what seemed like totally random results. I did produce a few good looking joints, but the inside corner ended up looking like Joe's picture even though the stock was exactly the same size.

Frustrated, but I will not give up on this!

[Ken Andersen]

Here are instructions that work fine for me
http://www.leevalley.com/en/wood/page.aspx?p=30119&cat=1,46168,46174

From your first photo, it looks like your bit is *very slightly* high, and your fence needs to expose slightly more of the cutter. The stock has to be
meticulously machined to the same thickness, flat, and straight, then held tightly to the fence at the cutter level. Slight errors get magnified in mitres!:)

[Mel Fulks]

I replied because I think that set up techniques can vary some and sometimes one wording will sound clearer to an individual than another.But the final result must make a neat corner .Those set up blocks are found useful by some and I don't doubt their experience. Some try to get exact center setup and that's where I see the blocks being the biggest help.As an employee I can't choose what species to use,I am called on to use woods that are easily torn out. For that reason I don't use exact center setup. If I set up vertical cut first and make sure that flat comprising part of the finished corner is smaller than the inside flat ,when I set up horizontal run and run a test piece ,adjusting fence but not cutter height it will fit vertical pieces ,or not ,the variance comes from intentionally not running the vertical pieces to a sharp point. With that part "missing "I might get a perfect fit just moving fence and not cutter height. If I do néed to adjust both the direction the cutter will have to move is UP. And due to thread slop,up is always the best way to adjust a shaper.better to make that adjustment two or three times than go too far.Once you accept that the fence must be moved ,coordinating the two adjustments will not be difficult. The horizontal pcs need a little original edge flat spot same as the vertical pce as mentioned in an earlier chapter ,after assembly there will be a tiny missing corner that is " filled" by sanding surfaces and slight rounding of corners. If you are using a soft easily cut wood like white pine where tear out is not a big problem you might be fine with exact center set up and sharp points on corners. But when you run the horizontal pcs you will still have to move the fence even though the cutter height is fine. I prefer my method because it will predictably produce good results on any wood. I can't go to management and say that half the pieces have to be replaced because big pieces have been torn out because "that's lousy wood". Same thing here as earlier, just different wording. Hope it helps. Well, I've got to go talk a passenger down in a plane .Pilot just keeled over. Good Luck !

[Alan Schaffter]

Now were getting somewhere...

Alan B...where exactly does is explain the process in the thread you linked...he talks about his new jig and the results but I don't see any info about how to do anything...

Alan S, interesting info for sure, and the results look great, but I'm still unclear as to how to get set up to cut these pieces...the only solution I think I've absorbed from this thread is that I need to get the height set, then cut the horizontal pieces, then carefully nudge the fence back until I lose the flat edge.

No that won't necessarily work. There are ways to do it that don't require my jig but I really can't address those adequately in a post, and frankly many of the "instructions" provided by retailers devolve into trial and error. It will be really hard to achieve the level of accuracy needed without my jig, but basically, now that I told you where the center of the profile is located, all you need to do is (1) use a pencil or marker to designate it, (2) use a marking gauge, center-finder, etc., to mark a centerline on the edge of one board (you need one in this case if they are the same thickness), (3) set the bit height so the "true center" of the bit aligns with the centerline of the board as it lays flat on the table, (4) temporarily clamp the board vertically to the fence then adjust the fence position so the centerline of the board aligns with the "true center" of the bit. If done carefully and precisely, and that may be extremely difficult without my jig, you should get a perfect joint. Use a test board to make sure the "knife edges" of test boards touch the table and fence on the outfeed side of the bit. Make very minor adjustments. Precision is the key to setting this bit.


Am I on the right track here? I do like your face frame round over idea, but I need to make some table legs so that's not in the cards. I did try that technique a couple of times and was not really pleased with the results...but maybe I'm too picky.

[Stephen Cherry]

No that won't necessarily work. There are ways to do it that don't require my jig but I really can't address those adequately in a post, and frankly many of the "instructions" provided by retailers devolve into trial and error. It will be really hard to achieve the level of accuracy needed without my jig, but basically, now that I told you where the center of the profile is located, all you need to do is (1) use a pencil or marker to designate it, (2) use a marking gauge, center-finder, etc., to mark a centerline on the edge of one board (you need one in this case if they are the same thickness), (3) set the bit height so the "true center" of the bit aligns with the centerline of the board as it lays flat on the table, (4) temporarily clamp the board vertically to the fence then adjust the fence position so the centerline of the board aligns with the "true center" of the bit. If done carefully and precisely, and that may be extremely difficult without my jig, you should get a perfect joint. Use a test board to make sure the "knife edges" of test boards touch the table and fence on the outfeed side of the bit. Make very minor adjustments. Precision is the key to setting this bit.

It seems that all this could be done with a handy dandy wixey digital height gauge.

Place the cutter at an arbitrary height, zero the height gauge on the bottom flat of the cutter, measure the height to the top flat, divide that by two gives the "first number".

Measure the thickness of the board and divide that by two also, for the "second number".

The "second number" - "first number" = required hight for the bottom flat on the cutter

The "second number" + "first number" = required height fot the top flat on the cutter.

Or something like that.

Fence would be set with a couple of test cuts so that the exposed height would be equal to the board thickness.

IN MY OPINION, A DIGITAL HEIGHT GAUGE IS SUPER HANDY FOR ROUTER AND SHAPER USE.

[Mel Fulks]

Sorry to hear that my way won't work... I ve written a book for naught. Wish I had been told 30 years ago. OH,well !

[Alan Lightstone]

Anyone try the Prazi Groove Center to setup and make lock miters?
http://www.praziusa.com/groovecenter.html

FWW gave it a good review:
http://www.finewoodworking.com/item/57484/groove-center-simplifies-lock-miter-joint

http://www.youtube.com/watch?v=WDY8Oi6DX5Y

Their demonstration seems to indicate a different part to center on than Alan Schaffter uses above.

[Alan Schwabacher]

I think the piece you cut vertically simply came away from the fence during the cut.

[Alan Schaffter]

It seems that all this could be done with a handy dandy wixey digital height gauge.

Place the cutter at an arbitrary height, zero the height gauge on the bottom flat of the cutter, measure the height to the top flat, divide that by two gives the "first number".

Measure the thickness of the board and divide that by two also, for the "second number".

The "second number" - "first number" = required height for the bottom flat on the cutter

The "second number" + "first number" = required height fot the top flat on the cutter.

Or something like that.

Fence would be set with a couple of test cuts so that the exposed height would be equal to the board thickness.

IN MY OPINION, A DIGITAL HEIGHT GAUGE IS SUPER HANDY FOR ROUTER AND SHAPER USE.

That only works for bit height if the center of the profile is halfway between the upper and lower flats. That is not necessarily true for all router bits and shaper cutters. That exact tip was the subject of an article or tip in one of the main WW mags within the last year. If you verify the top to bottom symmetry of the bit and correctly do the math then that will most certainly work for setting bit height for a "standard" lock miter joint (no offset and both boards are the same thickness). You may still need to mess with test cuts to set the fence set correctly. I think it would be very difficult to use the Wixey to set the fence position.

The Prazi (Valfor tools) Groove Center tries to do it- but just look the procedures and discussion of "M" the "magic number" (http://valfortools.com/m-calculation-diagram/) and the diagram and math used- Yikes!! and the price!!!!

http://valfortools.com/wp-content/uploads/2012/05/lockmiter23-675x519.jpg

[Alan Schaffter]

Sorry to hear that my way won't work... I ve written a book for naught. Wish I had been told 30 years ago. OH,well !

Not sure who you are referring to, but I never said any technique won't work, I said "may not necessarily work." The real answer is "it depends."

As I said in other posts, the lock miter joint requires precise setup of both bit height and fence position, that can be further complicated if the boards are different thickness unintentionally or not or you intentionally want an offset miter.

Here is one example- if the user sets bit height first, but does it incorrectly, then sets the fence so it results in a knife edge that is fully supported by the fence on the outfeed side of the bit, he will get a perfectly good "looking" miter cut on the horizontal board.

But, when he goes to cut the vertical board, if he set the bit height incorrectly, the vertical board will have either a blunted tip or the board will not be properly supported by the table on the outfeed side of the bit- resulting in a dig, gouged or scallop edge at the trailing end of the board- see the example in the Lee Valley instructions. (http://www.leevalley.com/en/wood/page.aspx?p=30119&cat=1,46168,46174) Lee Valley suggests this is normal for the bit (IT IS NOT NORMAL) and suggests using a wood frame, carry board, fixture, etc. support the board in both positions. Here is what they say (they call it a drawer lock bit):

"Note: When properly set up, the drawer lock bit removes the entire reference surface of the workpiece. This means that the outfeed end is not supported after passing over the bit and dig-in at the end is possible (see Figure 8)."

http://www.leevalley.com/en/images/item/Instructions/16J7508i22.jpg

[Mel Fulks]

I acknowledged that the way I do these is different from any instructions that I have seen. A hobbyist can ruin a couple of boards ,blame the cutter and or wood ,get more and proceed. My way no pieces are spoiled and nothing has to be made or calculated. The edges are left with with a bit of their original square edge intentionally and require no support in vertical position or offset fence for horizontal run. Not putting a sharp point on edges and climb cutting the inner corner away with round over assures there is no tear out. My point of frustration is Internet is more about voting and establishing consensus than finding a way to proceed. Don't think we are going to post anything that will change that. These are interesting things to try to explain and ,I guess,are best considered amusing pastimes .

[Jim Kirkpatrick]

Ok, time again for me to weigh in. As I said in an earlier thread on this topic (here is the link (http://www.sawmillcreek.org/showthread.php?199430-Sommerfeld-tools-easy-set-router-bit-setter)), most, if not all lock miter instructions are poor and many are downright WRONG. Sorry, Bill, but that includes Whiteside's instructions! When my Lock Miter Master set-up jig hits the streets in a few months, I'll post the complete instructions here on how a lock miter should be set.

The biggest problem with most instructions is that they attempt to use the center of the bit profile, but few if any (including Whiteside) correctly identify it!!! As soon as I find it, Ill post another drawing showing where the center is located, but look at the one below and follow my description, the HORIZONTAL AND VERTICAL center of a lock miter profile is at the intersection of the 45° cutting edge and the common male/female profile edge. That is the TRUE center and only that point!!! That point should be aligned with the centerline of the stock (equal thickness stock) when the stock is cut in the horizontal AND vertical positions. (The profile center and board centerline can also be used to make offset miters and miters in boards of unequal thickness but that is for another time/another post)

It "appears" that Bryan has the bit height set properly, but a lock miter needs both bit height and fence position set properly (for a standard joint), but guess what? The setting for one will affect the setting for the other! Also, the settings for both must be precises- "close" is not good enough! Since his fence is not set properly, it means his bit height is not correct either- or his stock is not the same thickness although in this case it looks like it is.

The joint he cut, which I call the offset joint, is not all that bad. If you cut faceframes with a flat tip you can round-over the corner without cutting into the other board. If the other board (cabinet side) is made from ply, it prevents you from cutting into and exposing interior plies. It is one of the techniques that is easy to do with my set-up jig. Here are drawings and photo of what I mean (imagine the light colored board is plywood):



Looking at Bryan's first picture, the bit height is set correctly, folks, this is how you set the bit up. Do not make it more complicated than it really is.

1. Bit height first, mill 2 pieces on the flat, until the pieces are flush with one another when mated together like they are in Bryan's first picture post. Done.

2. Fence position: Mill a test piece the same way as step one, flat on the table. Fence depth is correct just before the bit starts reducing the length of the work piece. the top leading edge should be a perfect 45 degree angle with a crisp edge. Period. If these are both correct, and you are still having your problem, there's something wrong with your technique. Either the vertical piece is not held tight to the fence or flush with the table top. You can use a feather board to help keep it tight to fence. Also make sure the fence top edge is parallel with the bottom edge.

Don't over think it, keep it simple. Bit height, fence position, good technique.

I'm not sure what Bryan is making with this setup, my guess is a drawer? I think carcass construction with the lock miter is a bit of an overkill. This setup shines for drawers.
The beauty of the lock miter is that once you get the bit setup, everything else is a breeze, including and especially the math. Say you have a 21" wide face frame opening, subtract 1" for the the slide on each side. And there's your math. Cut your front and backs precisely at 20" with some form of stop on the table saw or miter saw and then run them through the lock miter setup. Leaving an offset on what Alan calls the offset piece adds width to the drawer now you have to do more math and now there's more room for error. You might as well use a lock rabbit bit.
With the lock miter, you can easily cut and mill all the drawer joints for an entire kitchen in the morning before coffee break

[keith micinski]

Not to muddle things up because I have no experience but I have just ordered my first Lock Mitre cutter for my new to me shaper and after doing some reading I came to the same exact conclusion that Jim K. just stated. I think he is spot on with his setup process. As far as not using test pieces I have a bunch of fancy wixey gauges and while I use them and they usually get me dead on or close enough on my setup I will always do a test cut to verify my setup because it costs nothing and takes seconds to. Also everyone is getting all complicated about finding the center line of the bit, eyeball it, make two test cuts, and adjust accordingly. Finding center of the bit this way shouldn't take more then three adjustments and can usually been done in one adjustment. Once you find the center line of the bit and you make a test piece you keep it and use it as a setup jig getting you almost spot on every time. I would say the rest of you probably build things out of 3/4 inch material 95 percent of the time like I do and probably use your planer so your 3/4 is pretty much always the same like mine is.

[Alan Schaffter]

Jim's procedure will most definitely work.

If the thickness of Bryan's mated test pieces and the project stock are EXACTLY the same, then the bit height was set correctly. Bryan didn't show us the vertical test pieces however so he will need to tell us how he set the fence.

As others have already said, technique is important. If you don't firmly hold the stock down on the table and against the fence as you make the cutting pass, the 45° angle of the bit can lift the board from the table and/or push it away from the fence- scratch one joint.

As to my offset joint- it won't affect the length of a drawer front (width of the drawer). The fronts (and the backs if you desire) are cut to the exact length you want. No math involved. The drawer will be longer, front to back, however, by the width of the offset(s). (FYI, the offset can be set precisely, in 1/16" increments, up to a max of 1/4", using the secondary cursor marks on my jig.)

I'll end with a repeat of something I have already said- with lock miter bit height and fence setups, precision is important, and close is not good enough!

[Alan Schaffter]

Not to muddle things up because I have no experience but I have just ordered my first Lock Mitre cutter for my new to me shaper and after doing some reading I came to the same exact conclusion that Jim K. just stated. I think he is spot on with his setup process. As far as not using test pieces I have a bunch of fancy wixey gauges and while I use them and they usually get me dead on or close enough on my setup I will always do a test cut to verify my setup because it costs nothing and takes seconds to. Also everyone is getting all complicated about finding the center line of the bit, eyeball it, make two test cuts, and adjust accordingly. Finding center of the bit this way shouldn't take more then three adjustments and can usually been done in one adjustment. Once you find the center line of the bit and you make a test piece you keep it and use it as a setup jig getting you almost spot on every time. I would say the rest of you probably build things out of 3/4 inch material 95 percent of the time like I do and probably use your planer so your 3/4 is pretty much always the same like mine is.

Keith, I agree with most of what you said, except for a few points-

When I finally decided to start using my lock miter bit I surfed about a half dozen WW forums and found many, many woodworkers frustrated by this bit. Then I discovered that the instructions provided by bit manufacturers and vendors were confusing and often wrong. That is when I decided to design a little setup jig. If you understand the geometry and regardless of the setup method, practice with it, the lock miter bit becomes friendlier and easier to use, just like any woodworking process. But it sure can be a pain for the newby. Most of the available literature hasn't helped- just look at the Prazi stuff I posted earlier. I understand it, but thought there had to be an easier, more reliable way. There were two reasons I included info and drawings showing the correct profile center point - (1) most of the instructions provided by manufacturers and vendors had you use it but had it wrong (just look at them!), some were grossly wrong!, and (2) while my jig uses it, it does so automatically and precisely so the woodworker doesn't need to be concerned with it or even know where it came from. All he has to do is line up the board centerline with the jig cursors and he's done! (FYI, regardless of profile, the center point of every lock miter bit and shaper cutter is defined exactly the same- one jig fits all, except for a tiny lock miter bit. If the test cuts are off, does the newby know how to "adjust accordingly?" Isn't that how this thread started in the first place?

The second point, is 3/4" material. A large percentage of woodworkers buy standard A-C or birch veneer ply at big box stores - most of it is only 23/32", 11/16", metric, etc. thick, and not 3/4". That makes it hard to use setup blocks which are invariably 3/4" thick and complicates other set-up methods. If the drawer fronts are milled to 3/4" the lock miters may not mate properly with the plywood boxes unless the setup is adjusted. A 1/16" or 1/32" difference can make or break a lock miter joint. I found that just being off by the width of a (thin) cursor line or pencil mark can cause problems.

[Bryan Mills]

First, thanks to everyone who has responded and added information. I (and any others with the same issue) really appreciate it that people are willing to take their time and experience and try and help.

Jim, your process is exactly how I did it. The part that confuses me is that the flat on the vertical piece is not small, and while my technique may not be perfect, I feel as if I can't get such a large flat by poor technique alone. The flat on the vertical piece is the same width over the entire length so if I'm doing it wrong I'm doing it consistently wrong, haha. I am making table legs, that's the end game.

Alan...great info, release your jig already...I'll probably buy one.

[Pat Barry]

I have never used the bit, however, the problem to me boils down to the thickness of the wood being > 3/4". The fact that you can join the two boards edge to edge means the bit is centered on the thickness of the boards so that is a great start. That however could be accomplished with virtually any thickness. The fact that you are leaving a flat edge on the piece that is cut vertically tells me that the wood is too thick. As you noted, the only way to fix this is to move the fence backward. So, lets get a thickness measurement. I'm betting on it being about 1/16" over thickness. You might be able to plane the parts to thickness, but if it were me, I'd be finding this out at the time I was ready to machine the joint so planing would be very difficult without resorting to manual methods. I would go with two setups (one for the flat, and one for the vertical) and try to remember this the next time I went to make this joint.

[keith micinski]

Keith, I agree with most of what you said, except for a few points-

When I finally decided to start using my lock miter bit I surfed about a half dozen WW forums and found many, many woodworkers frustrated by this bit. Then I discovered that the instructions provided by bit manufacturers and vendors were confusing and often wrong. That is when I decided to design a little setup jig. If you understand the geometry and regardless of the setup method, practice with it, the lock miter bit becomes friendlier and easier to use, just like any woodworking process. But it sure can be a pain for the newby. Most of the available literature hasn't helped- just look at the Prazi stuff I posted earlier. I understand it, but thought there had to be an easier, more reliable way. There were two reasons I included info and drawings showing the correct profile center point - (1) most of the instructions provided by manufacturers and vendors had you use it but had it wrong (just look at them!), some were grossly wrong!, and (2) while my jig uses it, it does so automatically and precisely so the woodworker doesn't need to be concerned with it or even know where it came from. All he has to do is line up the board centerline with the jig cursors and he's done! (FYI, regardless of profile, the center point of every lock miter bit and shaper cutter is defined exactly the same- one jig fits all, except for a tiny lock miter bit. If the test cuts are off, does the newby know how to "adjust accordingly?" Isn't that how this thread started in the first place?

The second point, is 3/4" material. A large percentage of woodworkers buy standard A-C or birch veneer ply at big box stores - most of it is only 23/32", 11/16", metric, etc. thick, and not 3/4". That makes it hard to use setup blocks which are invariably 3/4" thick and complicates other set-up methods. If the drawer fronts are milled to 3/4" the lock miters may not mate properly with the plywood boxes unless the setup is adjusted. A 1/16" or 1/32" difference can make or break a lock miter joint. I found that just being off by the width of a (thin) cursor line or pencil mark can cause problems.


I agree with your comment about the plywood except my thinking was if I was using plywood for a majority of my projects then I would have set my bit up for that plywood. Nothing wrong with having a few set up blocks for the couple materials you use. Also, I guess I didn't mention when I am working with undersized plywood I make my "3/4" boards that thickness at the planer as well. My 3/4 is usually relative to what product I am working with. That having been said I do have a setup block for my planer that is set truly at 3/4 and will admit when I am making all my own wood I generally use that even though 31/32 would be fine to.

[keith micinski]

I may have been jumping to conclusions that everyone could look at the test cut and realize what adjustments need to be made. I have found there is no better we to learn and understand how things work then to do it the old fashion way and use test cuts and make adjustments. I am getting the impression from this thread I maybe one of the few people that actually enjoys this initial process:D this thread has actually made me excited to get that lock mitre bit here so I can take on the challenge of getting a system going to set it up.

[Bryan Mills]

I to enjoy the learning process...the frustration starts when I know what needs to happen but it does not make sense to my brain, haha.

[Bryan Mills]

Ok, round two...

I went over everything this morning meticulously, made sure the fence was 90 degrees to the table...and I'm getting the exact same result.

I ran a board through the planer and cut two pieces from it, they are the exact same thickness.

I set up the bit height and tried some test cuts, first two times they did not line up, third time I ended up with this

http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3308_zpsff0d85aa.jpg

Next, I moved the fence back until the board cut flat on the table was leaving a very small flat on the tip of the board

http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3310_zpscb075e5d.jpg

Once that was done, I processed the vertical piece and ended up with this

http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3313_zps154171be.jpg

that flat edge you see is uniform, and a hair shy of 1/8"...there is something very wrong here. If I move the fence back an 1/8", the pieces cut flat will lose 1/8" of their length (or width depending on what you are cutting) and would require a runner so as to not lose your position on the fence and the inside corners of the joint would not line up visually...

The other issue I see, is that if you look carefully at photo #2, there's a small flat vertical edge at the bottom of the cut. This tells me multiple things, the most important being that I don't believe that this bit can handle 3/4" material because the bit would have to be lowered in order for that flat to disappear.

Either I truly don't understand how this bit works...or there's something wrong with this bit.

[Alan Schaffter]

I may have been jumping to conclusions that everyone could look at the test cut and realize what adjustments need to be made. I have found there is no better we to learn and understand how things work then to do it the old fashion way and use test cuts and make adjustments. I am getting the impression from this thread I maybe one of the few people that actually enjoys this initial process:D this thread has actually made me excited to get that lock mitre bit here so I can take on the challenge of getting a system going to set it up.

Right on. When I designed the I-BOX and the Lock Miter Master the ultimate goal was to able to make box joints and lock miter joints with an easy set-up that required no math and few or no test cuts, and was repeatable. I have done that successfully with both jigs many, many times. That being said, I would never approach a project, especially one made from exotic or expensive wood, without doing at least one test cut.

Whole process of designing both jigs was initially just an exercise in trying to find a better way and learn something at the same time. I was lucky enough that both worked better than I could have ever imagined (I guess my licensees thought so too :) )


I have never used the bit, however, the problem to me boils down to the thickness of the wood being > 3/4". The fact that you can join the two boards edge to edge means the bit is centered on the thickness of the boards so that is a great start. That however could be accomplished with virtually any thickness. The fact that you are leaving a flat edge on the piece that is cut vertically tells me that the wood is too thick. As you noted, the only way to fix this is to move the fence backward. So, lets get a thickness measurement. I'm betting on it being about 1/16" over thickness. You might be able to plane the parts to thickness, but if it were me, I'd be finding this out at the time I was ready to machine the joint so planing would be very difficult without resorting to manual methods. I would go with two setups (one for the flat, and one for the vertical) and try to remember this the next time I went to make this joint.

Some truth here, but if you look at Bryan's photos, it doesn't appear that the stock is too thick. Most bits will cut stock within a range of thicknesses (e.g. 5/8" to 1-1/4") but all are different. If both boards are different thickness it does complicate the way you set things up and the cutting process, but that doesn't appear to be what is going on here. My jig references off the centerline of each piece of stock, but only when they are the same thickness. If they are not, then a separate setup is needed for one of the boards. The main reason for this is that the reference surfaces must face outward- the outside or good side of the horizontal board must face up while the good face of the vertical piece must face away from the fence. When assembled, the centers of each lock miter profiles must align with each other AND be the same distance from the OUTSIDE corner of the joint. If the boards are not the same thickness you must compensate by adjusting the the placement of the fence before cutting boards in the vertical position.

Setup using my jig can be done easily by using two reference lines by transferring the "X" (centerline) dimension (see drawing) from a board that will be cut in the horizontal position to a board that will be cut in the vertical board (regardless of which one is thicker). But . . . . . it must be a two step process- set the bit height and fence position to cut (ALL horizontal boards, then readjust the fence before cutting (ALL vertical boards).

These drawings of exaggerated mis-matches in board thickness should illustrate what I mean. A centerline is first marked on a board that will be cut in the horizontal position (dark board in the first drawing). That distance is transferred to a piece that will be cut in the vertical position. The distance is measured from the good/outside face, so is NOT a centerline, just a "reference line" on the vertical board (see second drawing). The bit and fence are first set (using my jig) to the centerline of the horizontal (dark) piece, then all dark pieces are cut in the horizontal position. The "reference line" on the light piece is then used to re-set the fence position before cutting all vertical boards. The bit height does not need to be adjusted. It is easier to do than explain! :)

http://www.ncwoodworker.net/pp/data/2580/medium/Unequal_Stock-3.jpg

http://www.ncwoodworker.net/pp/data/2580/medium/Unequal_Stock.jpg

[Alan Schaffter]

Bryan, what brand of bit are you using? Describe how you are setting the bit height and fence position. I think you may be compounding errors starting when you re-adjusted the fence and then used a miter gauge.

First, moving the fence "back" (away from the bit) when cutting boards in the horizontal position will NOT yield a flat tip- only moving the fence closer to the bit will do that! But also, lowering the bit will have the same result!

It looks like you are trying to use a miter gauge (in a miter slot) to support the stock as you feed the end of the stock across the bit. That WILL ONLY work if the fence is EXACTLY parallel to the miter slot (at all times) AND the face of the miter gauge is EXACTLY perpendicular to the fence (at all times). Try using a large square of ply or other wood to support the stock as you feed it- make sure the stock is against the table and the fence as you feed both horizontal and vertical pieces.

Also, are you sure the router/lift/bit is not slipping and changing height? How about the fence?

[Phil Thien]

Bryan, what brand of bit are you using?

Right there is the money question.

Bryan, where did you get that bit?

It was ground incorrectly.

[Mel Fulks]

Op said yesterday that he wanted to accomplish this feat without moving the fence .That infomercial is fascinating !....but unfortunately it mentions moving the fence.

[Alan Schaffter]

Right there is the money question.

Bryan, where did you get that bit?

It was ground incorrectly.

If the profile tip is too long he will get the gaps he shows, but it shouldn't affect the overall fit or strength of the joint. Now if the main cutting edge is not at 45° then the bit is worthless- That is possible if they did a bad job aligning the carbide when it was brazed to the bit body- that operation is often done manually.

[Alan Bienlein]

Bryan that piece on the left in the setup you just did still looks like it is up off the table. It doesn't take much to throw the cut off on this type of bit. I know first hand. Listen to Alan as I was having the exact same problem. I now have no problem setting up and using my lock miter bit.

Oh and mine is from MLCS.

[Phil Thien]

Bryan that piece on the left in the setup you just did still looks like it is up off the table. It doesn't take much to throw the cut off on this type of bit. I know first hand. Listen to Alan as I was having the exact same problem. I now have no problem setting up and using my lock miter bit.

Oh and mine is from MLCS.

That much though? We're 1/8" off there.

[Phil Thien]

What is the O.D. of the bit you're using? Is there any chance it is a bit intended for material up to 1/2" thick?

Bits for 3/4" thick stock are typically 2" or so in diameter. Bits for 1/2" stock are about 1-3/8".

[Bryan Mills]

The bit is from Elite tools, it's a cheapie... http://www.elitetools.ca/en/product/3-pc-jointing-router-bit-set-shank/

I described the procedure along with the last set of pictures, and it's EXACTLY what Jim does, but I'll try and be as detailed as possible here.

I measured my wood thickness, then scribed a center line and lined it up to the center point that you indicated by eye. Then I run two test pieces flat across the table. I then flip one and mate it with the other. If they line up flush as I showed in previous pictures, the height is right, if not, readjust.

Once I know the height is right, i move on to the fence adjustment. I move the fence either forward or backward in order to be getting a tiny flat edge on the very tip of the piece that gets cut flat on the table. If the edge of the piece is disappearing the fence needs to go forward, if there's too much flat on the tip, it needs to go back. Once that is set I then process the piece that runs vertically and the result is always the same...about 1/8" of flat at the tip when the piece that is run flat has virtually none...

I understand what you are saying about the miter gauge, but it seems as if that is fine as the squared end of the wood rests perfectly flat (no gap) against the fence and the miter gauge. Were they out of square or not perpendicular over any length it would be noticeable would it not? I'm not using it at all for the vertical piece. I clamped a runner to the vertical piece and press the face against the fence with a push pad from my jointer. I think...and please correct me if I am wrong, but all of the possible errors you mention would result in inconsistent cuts from side to side on the pieces. Looking at the pieces, the details (like the flat edge) are the same size and shape all that way across so I assume that eliminates those errors as possibilities?

Wish I had a way to try a different bit/brand...



The bit and/or fence are not moving, everything is very solid.

[Bryan Mills]

Bryan that piece on the left in the setup you just did still looks like it is up off the table. It doesn't take much to throw the cut off on this type of bit. I know first hand. Listen to Alan as I was having the exact same problem. I now have no problem setting up and using my lock miter bit.

Oh and mine is from MLCS.

It might be by a tiny hair...but there's no way that a hair is making a 1/8" difference...and I'm absolutely listening to Alan! This has all been very educational!

[Bryan Mills]

What is the O.D. of the bit you're using? Is there any chance it is a bit intended for material up to 1/2" thick?

Bits for 3/4" thick stock are typically 2" or so in diameter. Bits for 1/2" stock are about 1-3/8".

That was my thought too...and it's 1-3/4". However...I tried 1/2" stock (yes I lowered the bit and went through the procedure again) with the same results...

[Alan Schaffter]

The bit is from Elite tools, it's a cheapie... http://www.elitetools.ca/en/product/3-pc-jointing-router-bit-set-shank/

I described the procedure along with the last set of pictures, and it's EXACTLY what Jim does, but I'll try and be as detailed as possible here.

I measured my wood thickness, then scribed a center line and lined it up to the center point that you indicated by eye. Then I run two test pieces flat across the table. I then flip one and mate it with the other. If they line up flush as I showed in previous pictures, the height is right, if not, readjust.

Once I know the height is right, i move on to the fence adjustment. I move the fence either forward or backward in order to be getting a tiny flat edge on the very tip of the piece that gets cut flat on the table. If the edge of the piece is disappearing the fence needs to go forward, if there's too much flat on the tip, it needs to go back. Once that is set I then process the piece that runs vertically and the result is always the same...about 1/8" of flat at the tip when the piece that is run flat has virtually none...

I understand what you are saying about the miter gauge, but it seems as if that is fine as the squared end of the wood rests perfectly flat (no gap) against the fence and the miter gauge. Were they out of square or not perpendicular over any length it would be noticeable would it not? I'm not using it at all for the vertical piece. I clamped a runner to the vertical piece and press the face against the fence with a push pad from my jointer. I think...and please correct me if I am wrong, but all of the possible errors you mention would result in inconsistent cuts from side to side on the pieces. Looking at the pieces, the details (like the flat edge) are the same size and shape all that way across so I assume that eliminates those errors as possibilities?

Wish I had a way to try a different bit/brand...



The bit and/or fence are not moving, everything is very solid.

That all sounds good. The only thing I will say is that once the bit and fence are set for the horizontal board, no adjustment needs to be or should be made to bit height or fence position before cutting boards in the vertical position.

My only additional thoughts if none of the preceding is the root cause of your problem is you are overestimating what a "small" flat is. It doesn't look like a problem from your photo, but again, the slightest and I mean width of a pencil line error can result in a bad fit, but not the 1/8" offset you show. Too me it still looks like the bit is too low and the fence too close to the bit when you make the vertical cuts.

Is the collet/spindle of your router/shaper perfectly perpendicular to the top of the table?

[Joe Scharle]

Wow, this thread has developed some legs! I didn't see a pic of the OP's bit and it may have geometry problems, but first and foremost these bits are MITER bits with a locking feature added. If you cannot cut a clean edged miter (regardless of the lock position) you can not go any further with the bit.

[Bryan Mills]

SON OF A BIT...

I just made a discovery, thanks to Alan...the two 45 degree edges are indeed 45 degrees BUT THEY ARE NOT IN LINE WITH EACH OTHER!!!

http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3316_zps7f64dc89.jpg
http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3317_zpsc0115f0d.jpg

No wonder I've been beating my head against the wall...I had a feeling there was something wrong here. Why do I make the mistake of buying inexpensive tools...why? I know better.

Before anyone says it, yes, I am 100% sure that it is 45 degrees and that they are parallel with each other but offset. The picture may appear to tell a different story (looks like a slight angle) but it's simply parallax error.

[Phil Thien]

Boy, being right all the time is going to go to my head.

:)

[Alan Schaffter]

Boy, being right all the time is going to go to my head.

:)

I'll take a piece of that action! :D

Sure glad Bryan discovered the problem!

When you look at and think about the offset edges you realize when the two horizontal pieces are flipped, they will mate perfectly- the short surface to long surface, but when you mate a horizontal board to a vertical board you are attempting to mate a long surface to a long surface and short one to short one, essentially doubling the error visible in Bryan's last photo! (p.s. my jig won't properly mount to a bit with edges offset like that)

I know I often blindly trust my machines and cutters, so when something like this happens I often spend time looking for other problems when the real problem is staring me in the face. Lesson re-learned! What is that Sherlock Holmes quote? "When you have eliminated the impossible, whatever remains, however improbable, must be the truth"

p.s. I'll post when the Lock Miter Master is released. I'll include as much of (my version of) the manual as I can, so you can see what it will do and decide if it will be useful to you.

[Bryan Mills]

There was a brief moment where i actually thought that maybe I had no idea what I was doing, or that there was simply some small detail in the procedure that I was missing, but I felt all along that there was something more to it.

Thanks for everyone's input and suggestions though, there's some great info in this thread!

Alan...I will almost certainly purchase your jig as it sounds very intriguing and completely affordable.

[Alan Lightstone]

You're killing me, Alan.

You came up with the iBox, but I already had the Incra LS positioner Super System, so I couldn't justify buying one.

You are coming up with the Lock Miter Master, but I already have the Valfor Groove Master and 2-axis depth gauge, so I doubt I'll be able to justify buying one.

Plus I'm still waiting for you to manufacture (or license) your automatic pneumatic blast gates.

But can't you get them out before I buy things? Do I have to clear future purchases with you even before the OWMBO?

[Alan Schaffter]

You're killing me, Alan.

You came up with the iBox, but I already had the Incra LS positioner Super System, so I couldn't justify buying one.

You are coming up with the Lock Miter Master, but I already have the Valfor Groove Master and 2-axis depth gauge, so I doubt I'll be able to justify buying one.

Plus I'm still waiting for you to manufacture (or license) your automatic pneumatic blast gates.

But can't you get them out before I buy things? Do I have to clear future purchases with you even before the OWMBO?

:D :D :D Sorry about that! To make you feel worse (or not), the Lock Miter Master will cost a fraction of the Groove master, allow you to do more with your lock miter bit (offset and unequal thickness stock lock miter joints) and do it easier, requires no math or calipers, no table of lock miter bit "sweet spots", works with any brand of lock miter bit or shaper cutter, requires no "set-up spacers", has no moving parts, doesn't need to be set-up or calibrated, and on the downside or upside depending on your point of view (glass half empty/full?), is light enough and small enough to get lost among the lint and sawdust in your shop apron pocket! :)

Funny you mention my electro-pneumatic autogates/system- I never even thought about trying to market those- mainly because of the expense. Even by buying parts through Ebay and surplus and building the gate bodies from MDF, they still weren't cheap. All new parts would push the cost out of sight. However, MBright (http://www.ivacswitch.com/default.action?itemid=3), sellers of the IVAC/IVAC Pro auto switches was working on an electro-mechanical version of an autogate. They have a video of a working rapid prototype unit (see the first news release at this link (http://www.ivacswitch.com/index.action)). The release says it will be ready to ship May 2013. I sent them an email suggesting a few mods to help them avoid a couple of potential problems I saw with the design shown in the video. I haven't seen any more info about it and have no clue about price. Hopefully they won't find it too difficult to produce at a reasonable price.

I just started trying to market my new (old) high dust alarm for dust collectors, again. As many know, I designed a simple unit based on an inexpensive off-the-shelf lamppost day/night sensor. Despite its simplicity, it worked flawlessly for years, but I replaced it about four years ago with a totally new, purpose-built unit. The new has worked flawlessly since then. Years ago the only high dust alarm on the market was Oneida's synchronous motor/impeller based "Bindicator" which cost nearly $300! I contacted Robert Witter, Oneida's president, and initially tried to interest them in my primitive day/night sensor unit, but mentioned I also had a new IR-LED based unit almost complete. Witter agreed with me that a low cost high dust alarm was needed and said he would discuss it with his board/design team. He never got back to me. I eventually decided not to attempt to market the IR-LED unit because the following year Oneida started selling one of their own- what a coincidence- and i don't think the market is big enough for two. Lately, because of what I have read on a number of forums about issues with the operation and cost of Oneida's unit, I decided to give it another try. I have started slowly and so far have only contacted MBright. I think my unit would be great as an add-on or if totally integrated into their line of automatic DC switches. It is just an educated guess at this time, but I figure a manufacturer could have my unit built off-shore or here in the US and sell it for about half the cost of the Oneida unit, while making a decent profit. My which is slightly larger than a pack of cigarettes, has worked great for four years so is proven. Unlike Oneida's single sensor unit my has dual heads so has more mounting options. It has more capabilities than Oneida's- it has an adjustable false alarm rejection circuit, selectable alarm flash modes, an accessory switched output for an additional wired alarm(s), a second accessory output designed to be wired to main contactor to turn off the DC in a high dust condition, and finally can be easily modified to accept an optional wireless alarm flasher unit that can be placed near any shop outlet within a 100' or so of the main alarm unit for use where the DC and main alarm unit are not visible or where running wires to a remote alarm is a problem. I am waiting to hear back from MBright to see if they are interested.

Did I say I was retired? ;)

[Ken Andersen]

Too bad that the elite site doesn't provide any details about this particular bit. Could it be that, rather than being a faulty bit,
this bit was designed *exclusively* for "half blind" lock miters (which is what you are getting)?

[Bryan Mills]

Doubtful...the picture on the site and in the box shows a standard lock miter joint...

[Alan Lightstone]

I just started trying to market my new (old) high dust alarm for dust collectors, again. I eventually decided not to attempt to market the IR-LED unit because the following year Oneida started selling one of their own- what a coincidence ;)
I have Oneida's. Swing and a miss again. I keep trying to be one of your customers (the engineer in me appreciates your designs), but I'm always a little late to the party it appears. :(

Anyway, I digress. Back to lock miter bits (which I too find very frustrating, but have made a beautiful drafting table using mine. But this is after buying 3 different bits until I could get decent joints.

[Bryan Mills]

What bit did you end up liking and which were the two that did not make the grade?

[Carl Beckett]

There was a brief moment where i actually thought that maybe I had no idea what I was doing



For me, this isnt just a brief moment......

[Joe Scharle]

You might pick up something from this video...

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_lockmiter.html?tab=1#TabbedPanels1

[Alan Lightstone]

I'll have to look next week when I get home. It's been a while.

[Mike Leung]

I just crawled out from piles of sawdust after spending a weekend making quadralinear legs for 2 morris chairs and a post for a hall tree. I sure wish I had your tool Alan. It was my first time using a lock miter bit and it took me 12 test cuts to get the bit set up right. I think I should be able to get it in 4 or so next time. I also constructed a jig to hold my leg pieces in place during the cut. It worked out really well. The long post was held down by just featherboards and I had a couple of wobbles so I had to do some clean up work afterwards. Overall, I am happy with the joint. I was using a large Amana bit and the cuts were smooth and clean for the whole run of 72 cuts.

Here are a couple of pics.
Some of the profiles might look strange on the inside surface because the oak was left over from a flooring project. Some are flat while the others have a profiled bottom. So ignore the inside surface. I'm just using up the wood from the old project whenever can.
The jig holds the pieces horizontal on one side and vertical on the other.

Alan, can I beta test the tool when ready?

[Bryan Mills]

Looks great Mike. You should provide some more detail on your holder, looks cool!

[Alan Schaffter]

Nice legs! (says one guy to another :D ).

It doesn't help set the bit, but using a carrier jig like Mike's can prevent some typical lock miter issues if the setup is not correct (tip is removed) or you are using soft wood where the tip may not be strong enough to support the board. I believe Lee Valley's instructions recommend using one because they claim the old edge will be completely removed- the new tip (edge) will be offset from the uncut edge. The stock won't be adequately supported throughout the cut so can result in a gouge near the end. In addition to being long enough for your stock, the carrier must secure the stock firmly, and support it for the entire length of the cut. The bit/fence setup must allow for it.

Tommy Mac sometimes uses a similar technique when cutting bevels on a table saw- rather than using a carrier jig, he temporarily glues a second board to the top of the stock so there will always be a solid, uncut edge against the fence. He removes the second board and uses a plane to clean up the surface of the stock. Some lock miter bit vendors include a similar technique in their instructions.

Another tip- Rather than use feather boards to ensure narrow stock maintains good contact with the fence (doesn't bow, isn't pushed away from the fence or the table), I sometimes use a jointed and waxed board as secondary fence to trap the stock- I set it with pieces of stock. The secondary fence also provides a little protection for hands and fingers and forces you to use a push stick.

http://www.ncwoodworker.net/pp/data/2580/medium/IMG_43312.JPG

http://www.ncwoodworker.net/pp/data/2580/medium/IMG_43322.JPG

[Chris Padilla]

Well, I'm all anxious to go dig my lock miter bit out of the drywall in the corner of the shop and try it out again! I think in rage I might have ripped it out of my router table and flung it but I don't quite remember.... :)

[Joe Scharle]

This works for me..

256217

[Mike Leung]

Looks great Mike. You should provide some more detail on your holder, looks cool!

The hold is really simple. I just made compartments that fit the pieces perfectly. I had 2 lengths so I built the holder for the longer length and screwed in blocks to make the compartments to fit the shorter pieces. The pieces were snug so I did not need to screw them on. The end caps both hold the pieces in an also backs the pieces up to prevent tear out.

The holder makes this cut very safe and precise.

Half the time in my shop is making jigs and holders.
I made a couple of fence spacers to allow shallower cuts. They just hook onto my jessem fence and I stop them away to run multiple passes.

[Mike Leung]

I should have ran my long 80" pieces this way. The feather boards worked up until the end when the boards wobbled. This would have held them in place until the cut was completed.


Nice legs! (says one guy to another :D ).

It doesn't help set the bit, but using a carrier jig like Mike's can prevent some typical lock miter issues if the setup is not correct (tip is removed) or you are using soft wood where the tip may not be strong enough to support the board. I believe Lee Valley's instructions recommend using one because they claim the old edge will be completely removed- the new tip (edge) will be offset from the uncut edge. The stock won't be adequately supported throughout the cut so can result in a gouge near the end. In addition to being long enough for your stock, the carrier must secure the stock firmly, and support it for the entire length of the cut. The bit/fence setup must allow for it.

Tommy Mac sometimes uses a similar technique when cutting bevels on a table saw- rather than using a carrier jig, he temporarily glues a second board to the top of the stock so there will always be a solid, uncut edge against the fence. He removes the second board and uses a plane to clean up the surface of the stock. Some lock miter bit vendors include a similar technique in their instructions.

Another tip- Rather than use feather boards to ensure narrow stock maintains good contact with the fence (doesn't bow, isn't pushed away from the fence or the table), I sometimes use a jointed and waxed board as secondary fence to trap the stock- I set it with pieces of stock. The secondary fence also provides a little protection for hands and fingers and forces you to use a push stick.

http://www.ncwoodworker.net/pp/data/2580/medium/IMG_43312.JPG

http://www.ncwoodworker.net/pp/data/2580/medium/IMG_43322.JPG

[Bryan Mills]

So I went and bought a craftex lock miter bit...spent 10 minutes or so setting up and got this

http://i2.photobucket.com/albums/y36/Ptownkid/Wood/100_3365_zps372dd548.jpg

That's more like it! Joint is slightly looser than I expected, thought it would go together a little snugger, but I'm sure I can adjust it slightly to achieve that.

[Mel Fulks]

That's great Bryan. That was a tough one .Next time someone has trouble with it ,you get to do some of the writing!

[Mike Leung]

looking good Bryan

[Bryan Mills]

That's great Bryan. That was a tough one .Next time someone has trouble with it ,you get to do some of the writing!

Absolutely..I'll pay it forward for sure, but I'll start with "check the bit".

[Bryan Mills]

looking good Bryan

Thanks Mike! Makes me feel a whole lot better that's for sure.

[Alan Schaffter]

Mucho better!

When you think about it, making that bit has to be a precision CNC process- for a nice tight joint regardless of the other alignment issues, the male profile must match the female profile exactly. A good CNC grind is essential.

FYI, the Lock Miter Master is a little closer to reality. Manufacturing proof prototypes are expected in the next few days. They will inspected and tested, and if all goes well it will be time for the first production run. In the meantime, there is still a bunch of other stuff to do like packaging, instructions and/or video, advertizing, a little patent work, etc. etc. before they can actually hit the market.

[Jim Kirkpatrick]

Jim's procedure will most definitely work.

As to my offset joint- it won't affect the length of a drawer front (width of the drawer). The fronts (and the backs if you desire) are cut to the exact length you want. No math involved. The drawer will be longer, front to back, however, by the width of the offset(s). (FYI, the offset can be set precisely, in 1/16" increments, up to a max of 1/4", using the secondary cursor marks on my jig.)



Alan, I can not believe anyone would orient the drawer in the manner that you suggest. It's structurally unsound. It should be rotated 90 degrees. I.E., the sides of the drawers are routed vertically and the front/backs routed horizontally not the other way around. Granted, if you're using mechanical drawer slides and modern glues, it shouldn't be a problem and come apart, but why chance it?

Glad to see you found a solution, Bryan. My advice to anyone buying a lock miter bit, Whiteside can't be beat. Free shipping on orders over $29 at woodworkersworld.net. No affiliation.
http://www.woodworkersworld.net/45_degree_lock_miter_router_bit.shtml

[Alan Schaffter]

Alan, I can not believe anyone would orient the drawer in the manner that you suggest. It's structurally unsound. It should be rotated 90 degrees. I.E., the sides of the drawers are routed vertically and the front/backs routed horizontally not the other way around. Granted, if you're using mechanical drawer slides and modern glues, it shouldn't be a problem and come apart, but why chance it?

Glad to see you found a solution, Bryan. My advice to anyone buying a lock miter bit, Whiteside can't be beat. Free shipping on orders over $29 at woodworkersworld.net. No affiliation.
http://www.woodworkersworld.net/45_degree_lock_miter_router_bit.shtml

I wouldn't attach the fronts that way either, though with the additional glue surface provided by the lock miter profile it would probably be plenty strong. I only suggested it if for some reason, a builder wanted to move the miter "around the corner" and possibly round over the point. It is more appropriate and in fact almost necessary for assembly to do it that way when attaching face frames to a ply box using lock miters. (The corners of the faceframes must be mitered too, because the lock miters intersect at the corners.)

I still need to wrap my brain around the setup a little more and test it, but, I think it is possible to reverse the profiles for the stronger joint, and still put an off-set joint on the drawer fronts. The joint would be similar to a half blind dovetail where the miter is not visible until you open and can see the sides of the drawer. I think the procedure would be like this: (1) Do a standard lock miter bit height and fence set-up, (2) cut both ends of all the sides in the vertical position, (3) lower the bit by the desired amount of off-set (set-back) but do not adjust the fence position, (4) cut both ends of all drawer fronts and backs in the horizontal position.

Lock Miter Master Update: My licensee received manufacturing proofs and said they worked perfectly on the first try! He is sending them to me for a final test before starting production- things are moving fast!!!