Alternative approach to cutting tenons

[Brian Holcombe]

I don’t own a table saw, and secretly hate referencing square off of the end grain. These cuts were ultra-critical so I decided to use the knee mill.

Instead, the vise is indexed off of the mill and head trammed square. Can’t get much more square then this.

https://youtu.be/6vp1Gb7QvCQ

[David Eisenhauer]

Overkill Brian? What will you do for Ultra-Ultra Critical cuts when that need arises?

[Mike Cutler]

Brian
Do you have any idea how many jigs and fixtures manufacturers you could put out of business???
All kidding aside, that's pretty cool.:cool:

[Bill Adamsen]

You should be lubricating that cut ...

[Brian Holcombe]

Thanks gents!

Bill, that’s a good one!

[Van Huskey]

Overkill Brian? What will you do for Ultra-Ultra Critical cuts when that need arises?

Actually for Brian that may be underkill. You should check out his video of the piston fit inserts in a caddy he made to house dirt balls*. It is on his youtube channel.


* no offense intended to the skill it takes to make those fine dirtballs, calling them dirtballs instead of dorodango produced more impact in my sentence. :o

[Matt Mattingley]

Brian you’re the man! I use my Bridgeport now and then for woodworking. Some people wonder how I made certain cuts so precise. You forgot to show how you left a 0.0625” radius fillet in the corner for strength and used a Micrometre to leave .001 for glue tolerance. lol.

Edit; I do love how you added a lightening hole to your set up block. Your set up block is wood right???

[Brian Holcombe]

Haha, they are neat balls if dirt, aren’t they?

Glad that you guys enjoyed this bit of craziness. I’ve been on a Bridgeport binge lately as it makes certainly chair related cuts very easy (like angled round mortises) and thin bridle joints.

I dragged home a rotary table for it and spent the evening cleaning it up and putting it back into working order. It had a nice chuck on it as well that was also rusted to hell, so I cleaned that up as too.

I’ll take some video of the work I do with it, which will also be chair related.

[Dave Zellers]

Geeze. And here I thought you were a Neanderthal.

Are you going to be cutting tenons with lasers guided from space next?

If I were you, I would buy a table saw just for the street cred.

[Brian Holcombe]

Matt, it’s oak, hehe, not quite aluminum, brass or steel but it works in a pinch :)

I set it up as a stop, so the hole is for a bolt that goes through to a t-nut.

[Brian Holcombe]

Geeze. And here I thought you were a Neanderthal.

Are you going to be cutting tenons with lasers guided from space next?

If I were you, I would buy a table saw just for the street cred.

Both, I decided at some point last year that I needed to add good machinery and basically use all of the tools available to me; hand and machine.

[Dave Zellers]

:) :cool: :D

[Matt Mattingley]

Matt, it’s oak, hehe, not quite aluminum, brass or steel but it works in a pinch :)

I set it up as a stop, so the hole is for a bolt that goes through to a t-nut.
I look forward to your future videos, especially if your surface grinding , Cyl grinding or jig grinding wood (or wire/sink EDM) more lol.

[Greg Parrish]

Cool video. All I kept thinking was I sure hope there is no way that blade could come off. Don’t know why that would worry me more than a table saw arbor but that’s what my head went to first. LOL

[Brian Holcombe]

Hah! Given the current technology maybe a wire edm for wood isn’t far off, lol.

I might setup a few blades on a single arbor for cutting double tenons on stuff I do all the time (like chairs).

[Jim Becker]

The mill clearly does nice work, albeit not at moon rocket speed. :) And using all the tools available for whatever they do best isn't a horrible thing. Machines and all those beautiful hand tools on your wall can and should coexist very nicely together; they each have their advantages and compliment the other. IMHO.

[Brian Holcombe]

Thanks Jim! I’m finding it handy to tool up the mill. I agree totally that the two coexist nicely. There are many things where it is effective to work by hand and others where it is very handy to be able to make very accurate and repeatable cuts.

[Chris Parks]

I have seen a Bridgeport used to cut box joints many years ago.

[Derek Cohen]

Brian, words fail me! :) That is some machine. I know that it was set up for fun, but how much time would it actually take to do from scratch if for real?

I suspect that this post was partly, if not unconsciously, a response to my post on WoodCentral, where I showed my set up for using power tools to make M&T joints. I did not post it here as I am in awe of the machinery that is so often on display. My default is still to return to hand tools, although I have used power tools for at least three decades. Anyway, I cannot link to the WC post, so offer an abridged (as opposed to Bridgeport) version of my quick route to tenon cutting.

It uses the tablesaw for shoulders, and the a spacer on the bandsaw for the cheeks. The mortice was first routed out. I work with reference sides, rather than exact centering, so exact positioning is not important.

First the shoulders are defined on the tablesaw .....


https://s19.postimg.cc/vmdyqa1k3/2a.jpg


The bandsaw is set up to saw the cheek furthest from the fence. The reference side faces the fence.


https://s19.postimg.cc/fbdutzjxf/3a.jpg
https://s19.postimg.cc/ovxhgum43/4a.jpg

This spacer is for a 8mm or 5/16" wide tenon/mortice (in the current build). The measurement is the width plus the width of the bandsaw blade kerf.


https://s19.postimg.cc/djkvz38ab/5a.jpg

Place the spacer against the fence, and saw the other cheek without moving the fence ...


https://s19.postimg.cc/djkvz3npv/6a.jpg
https://s19.postimg.cc/7vel86oib/7a.jpg

You can see that the beauty ends of the tenon still need to be removed.

Regards from Perth

Derek

[Chris Parks]

I reckon the router table with memory will top the lot but I can't link it here so look in the Oz forums/router tables for the build. :)

[Brian Holcombe]

Derek, Hah, no that was a serious job. I'm building chairs currently and so the process is often short production runs. I'm finding that as I build a lot of them I prefer exact duplicate parts rather than hand-fitting each joint. The more accurate and hefty the machine, the more often those parts are actually identical.

I save the handwork for the shaping and so forth which is time consuming but it is very necessary for the finished product.

I have a variety of methods which I employ; Bandsaw, router table, handsaw and now also Bridgeport mill. Really what I would like to be doing is cutting these with a shaper or tenoner. The trouble with a bandsaw, router table method is that it's multi-step and so more time consuming than the bridgeport even though the Bridgeport feeds stock slowly, but it can be quite accurate, nearly as accurate as the bridgeport if the work is done carefully. The minor things which effect accuracy on the router table do not on the bridgeport. IE when work is clamped into a milling machine vise it doesn't move out of position but work held into position against a stop can move on a rare occasion. Those occasions tend to happen enough to be annoying when you're doing a five-step cutout with multiple setups.

I can also do things to turn up the rate of progress on the bridgeport.

Truth be told I did not have that thread in mind, specifically, but I suppose I've been thinking about it more now that the thread is going.

[Chris Parks]

When I saw Derek showing how the spacer works the lights came on and I thought it was a terrific idea. The router with the fence I have an issue with but it is my own personal dislike of hand held routers with the factory fence used in a similar fashion, I just can't get past how easy it is not to be accurate but if it works for Derek so be it.

[Brian Holcombe]

I hesitate to reference to the length of part when setting stops, at times, it introduces another place for error to accumulate. Unless the stop is perfectly square and contacts the entire face of the part there will be a good chance that the referred length will be slightly different as the part is turned because the stop is contacting the part differently as it is turned unless both faces or one face is perfectly square.

When I've cut tenons with simple tooling (router table) I've gotten the most accurate parts by cutting one joint using the fence as a stop, then cutting the opposing side using a stop which contacts the tenon shoulder. This resulted in parts which had totally square shoulders and which repeated their lengths precisely.

Ideally, one clamping should result in the entire cutout, but that's impossible with most of my tooling.

This is the result when using the router table, I'm pretty happy with this. These are double tenons, fully shouldered.

https://brianholcombewoodworker.com/wp-content/uploads/2018/09/WADma7cVQBmxmGsQTBs2Xw-3032989807-1536457803620.jpg

[Brian Holcombe]

When I saw Derek showing how the spacer works the lights came on and I thought it was a terrific idea. The router with the fence I have an issue with but it is my own personal dislike of hand held routers with the factory fence used in a similar fashion, I just can't get past how easy it is not to be accurate but if it works for Derek so be it.

The spacer is a slick way to do it, beats resetting the fence. I actually had not been thinking of that which is why I'm glad when these discussions come up as these sort of things pop-up.

[Chris Parks]

I don't know why but I find stops not to be as accurate as they should in theory be and I wonder if it is because they are made of wood, don't ask me why but I wonder if they were made of a harder material such as aluminium or a solid plastic they might give a better result.

[Mike King]

If you like repeatability and accuracy, a shaper would might be an improvement in function. And quicker.

[Van Huskey]

Is there some kinda weird supermoon or is Mars in retrograde? Brian and Derek both over here using electric pixies. I am afraid to go to the Neander forum, a bunch of machine guys may have crossed over and be there in a cat fight over bevel angles and chip breakers.

[Brian Holcombe]

There is a good chip breaker thread getting started over there, hehe.

Chris, it's likely due to what I mentioned above, that end grain slightly out of square has a consequence in how it translates to the cut. As you rotate the length is effectively different and that shows up in the shoulder.

Mike, I agree, I'm on the hunt. I just missed a Hofmann shaper and have been kicking myself. I'll probably end up getting a Minimax TW55ES.

[John Goodin]

Maybe I will show this to my wife and say I need a machine like that but will settle for a better drill press.

[Matt Mattingley]

I don't know why but I find stops not to be as accurate as they should in theory be and I wonder if it is because they are made of wood, don't ask me why but I wonder if they were made of a harder material such as aluminium or a solid plastic they might give a better result.
Sometimes I use gauge blocks or gauge pins. Sometimes when you’re looking for a specified size, the blocks and pins will be your friend. If there are odd size blocks or pins, you just surface grind or cyl grind to suit your needs and add it to your arsenal of fixtures.

I might measure the size of a hole or pocket very differently then Jim, John or Ed. To each his own.

[Matt Mattingley]

Yes
Is there some kinda weird supermoon or is Mars in retrograde? Brian and Derek both over here using electric pixies. I am afraid to go to the Neander forum, a bunch of machine guys may have crossed over and be there in a cat fight over bevel angles and chip breakers.
Chip load, attack angle and chipbreaker are all very important features of handling the chip and the heat. As often as possible you want to put the heat into the chip and not the cutter.

This takes things to a whole new level. This now starts getting into metallurgy, chip size/Displacement management and chip/tool heat management, feeds and arbour tool speed’s.

Most saw blade companies use silver solder or brass solder brazing. Silver solder handles more heat.
The higher the attack angle in degrees the sharper the tool and reducing tear out. But, this comes at a price of resharpening more frequently.

Ideally for wood using a blade style 15° (For Long life) is the best attack angle. This attack angle changes depending on how high a blade is above the surface. And… The surface feet per minute of the blade and… The chip load and The feed ratio and… The hardness and sharpness of the tooth, and the hardness of the wood. What you’re cutting has a hardness usually measured in janka scale. For metal a ball bearing or diamond which is called a Rockwell scale.

Don’t expect cutting pine vs IPE to be the same. IPE is sitting up there at the top of the hardness of woods. I’ve been cutting a lot of it lately. Don’t expect your same tooling to do the same trick at the same speed for the same amount time.

Most hobbyists are not looking for longjevity and efficiency during production runs, of a cutters reliability. This starts to become efficiency factor for guys who are running CNC machines.

I am retired, but CNC machines were my forte for almost 20 years. I’m not a stranger!

[Jacques Gagnon]

Brian,

have you tried using microns as your measurement units?🤓

your work is impeccable as well as impressive; kudos!

J

[Brian Holcombe]

Thanks Jacques!

Appreciate the insights Matt! That set of pins is quite nice.

[Brian Holcombe]

These things are not quite popular anymore, with the advent of CNC but they're handy for the manual knee-mill. This one was relegated to the junk pile, my dad picked it up a long while back (about 15 years) and it sat around his shop for that long, the two parts having been separated (chuck from table) for some time but whoever made it really had their act together as it features a brass locating pin that is hefty. Still, for some reason when I found it the jaws were out of alignment (self aligning jaws need to be inserted in order) and the chuck frozen. The rotary table turned only in one direction and the lock did not work.

Both were completely broken down, cleaned and inspected. What was probably 20 years of brass and aluminum filings removed from both. Then greased and readied for battle.

In any case, Troyke I knew, but I looked up Buck chucks and after I picked my jaw up off the floor I thought it best to get it back into working order. I love aesthetic restorations but usually settle for simply getting things in working order.

Both were rusted heaps on friday, I polished up both, but took the table to a high finish so that the markings are very visible.

https://brianholcombewoodworker.com/wp-content/uploads/2018/09/fullsizeoutput_84e.jpeg

https://brianholcombewoodworker.com/wp-content/uploads/2018/09/fullsizeoutput_851.jpeg

https://brianholcombewoodworker.com/wp-content/uploads/2018/09/fullsizeoutput_84f.jpeg

Turns out there is a locking flange nut on the backside of the table, it must be locked into place or the table rotation will tighten it as the table is turned allowing it to turn in one direction. Hah. So, the flange nut was locked in place upon reassembly. The lock was an easier fix needing only be tightened slightly.

[Mike Cutler]

Really what I would like to be doing is cutting these with a shaper or tenoner.

Using a shaper to make tenons is very nice.
It cost a couple hundred $$$$ to get set up the first time. After that it's just so easy, and fast, to make perfect tenons. All it takes is a dial indicator on a mag base and a vernier caliper.

I still like your Bridgeport method though.

[Jared Sankovich]

Using a shaper to make tenons is very nice.
It cost a couple hundred $$$$ to get set up the first time. After that it's just so easy, and fast, to make perfect tenons. All it takes is a dial indicator on a mag base and a vernier caliper.

I still like your Bridgeport method though.

As little as a hundred if you only use one head and just raise or lower the spindle for the second cheek cut.

The knee mill is a interesting solution, and I've used my mill and metal lathe for wood cuts myself in the past. However wood dust isn't the greatest thing when mixed with way oil for the ways of precision machine tools.

[Peter Christensen]

Doesn't you knee mill have power feeds? :)

[Brian Holcombe]

It has one for the x-axis (table) but the saddle is in need of repair at the moment so I wind it the saddle by hand.

If I do this again I will turn the vise 90 degrees and perform the cut using the feeder.

If the tools are sharp the cutter is producing shavings, not dust, and the machine is cleaned after each one of these processes, then wiped down carefully at the end of the day.

[Dave Cav]

Really what I would like to be doing is cutting these with a shaper or tenoner.

Yeah, a tenoner would be fastest and potentially the most repeatable. And then to keep the Neander flavor, you could join the current discussion over at OWWM about square tenoner heads vs insert heads.

[Brian Holcombe]

Thanks for pointing me to that thread, Dave! Reading along.

I flip back and forth as I would like the multi-tasking ability of a sliding table shaper, but a dedicated tenoner seems a better tool for the job in many ways.

Mark Hennebury pointed me toward the Balestrini tenders recently, those look really awesome but I assume can only cut rounded corners? I dont know if they can be made to cut square corners but I like that they cut a full shoulder in one motion.

[Mark Hennebury]

Thanks for pointing me to that thread, Dave! Reading along.

I flip back and forth as I would like the multi-tasking ability of a sliding table shaper, but a dedicated tenoner seems a better tool for the job in many ways.

Mark Hennebury pointed me toward the Balestrini tenders recently, those look really awesome but I assume can only cut rounded corners? I dont know if they can be made to cut square corners but I like that they cut a full shoulder in one motion.

High Brian,

The Balestrini TAO that i discussed with you is only made only for round end. you can of course do a square end with only top and bottom shoulders, if you go past the with of the wood. or you can trim the round ends as a second op. There are some auto tenoners that do round or square i believe, but they may CNC. The Balestrini could maybe be made to do square end, but it would require some major alteration as it operates on a pin tracer system, you would have to remove the round end templates or attached straight ones over top. I think it could be done, but like i said, not easily.

[Brian Holcombe]

Thanks Mark, very much appreciate your insights!

[Jared Sankovich]

Thanks for pointing me to that thread, Dave! Reading along.

I flip back and forth as I would like the multi-tasking ability of a sliding table shaper, but a dedicated tenoner seems a better tool for the job in many ways.

Mark Hennebury pointed me toward the Balestrini tenders recently, those look really awesome but I assume can only cut rounded corners? I dont know if they can be made to cut square corners but I like that they cut a full shoulder in one motion.

Imho a shaper adds a lot of versatility in addition to being able to cut tenons. Adding a tenoner after you already have a shaper or two makes the most sense (to me anyway) even if its a powermatic with millbury heads

[Brian Holcombe]

If only I could put two shapers in my workshop, haha!