Jointer noob

[john schnyderite]

I got my jointer, set it up. on short test pieces everything seemed perfect. I ran some longer boards that are a bit more bowed and I'm having more issue getting them straight. I'm not sure if my technique is wrong. It seems like the beginning of the board takes a decent amount of material, but by the end its not taking any. Any tips or things I might be doing wrong.

[johnny means]

Sounds like you're angling your board downwards by pushing the leading edge down to the table with the board bowing upwards. Try running your boards with the ends bowing down into the table.

[Mel Fulks]

If the outfeed table is too high the wood climbs and less material is removed. One and one half thousands is enough to cause problems. Can be caused by a small knick or just slight dulling.

[Andrew Hughes]

I agree with Mel. Lower the outfeed table a very small amount

[Keith Westfall]

Make sure you are maintaining downward pressure on the board on the out-feed side and not on the in-feed side.

[john schnyderite]

by too high, do you mean one of the sides of the outfeed is not coplanar and sitting high?

i am trying to run the boards so that the bow is making a frown..where should i be putting pressure as i run the boards through?




If the outfeed table is too high the wood climbs and less material is removed. One and one half thousands is enough to cause problems. Can be caused by a small knick or just slight dulling.

[andy bessette]

Why have you not mentioned what jointer you have?

[Derek Cohen]

John, do not make any adjustments to your jointer until you are absolutely certain it is the machine and not the human! It is most likely the human.

I would begin by scribbling on the underside of the board, so as to monitor what the cutter is doing. It should remove waste from the extreme ends first.

Of course the board may also have a twist, and this can be affecting the way you transfer downforce as the board moves along the bed. Downforce and hand positioning is likely to be the issue with your troubles (regardless of twist). Take light cuts and observe what is happening, then report back your observations to the forum.

Regards from Perth

Derek

[jack forsberg]

What Mel said the rear table is to high or the cutter block to low . I’ve never experienced anything requiring supernatural technique to use a jointer when it’s properly set up.

Here is how you do it
https://www.instagram.com/p/BiCXbm5gBCc/

[Mel Fulks]

John, they can be run either way. I do the best edge with out regard to which will be easiest. Keep the stuff held down to contact outfeed table. For a "smile" edge it's ok if first pass does not cut the end,just run it again.

[Al Launier]

Make sure you are maintaining downward pressure on the board on the out-feed side and not on the in-feed side.
I'll emphasize Keith's comments: Downward pressure on the board only when it is on the out-feed side letting the tail end of the board assume its natural "float" position as it passes over the cutters.

[Chris Merriam]

I agree on changing the table height, using straight edges and setup tools gets you started, but if you’re not getting the results you need then you have to make adjustments and test the results until you’re happy.

You also need to consider the board length. If it’s longer than the outfeed table then as it leaves the outfeed side (and it’s bowed) then that can start to alter the physics of everything. Start with a board that is no longer than your outfeed table, whether it’s bowed or not, and make sure the blades are cutting from end to end (might take a few passes).

[johnny means]

384953

This would be my first guess as to what you're doing.

[john schnyderite]

I ran a smaller board though which had a bow. I ran it 'frown'-wise. Here are some photos of the result after 3-4 small passes. I focused pressure only on outfeed side while running though. It seems to take more material on the side that is run through first. The front of the board is already .1" thinner than the back side of the board though the bow makes it appear that material should be coming off the back too. I noticed this also when running longer boards.

https://photos.app.goo.gl/zTyvAxRbQGkgjmdt2




John, do not make any adjustments to your jointer until you are absolutely certain it is the machine and not the human! It is most likely the human.

I would begin by scribbling on the underside of the board, so as to monitor what the cutter is doing. It should remove waste from the extreme ends first.

Of course the board may also have a twist, and this can be affecting the way you transfer downforce as the board moves along the bed. Downforce and hand positioning is likely to be the issue with your troubles (regardless of twist). Take light cuts and observe what is happening, then report back your observations to the forum.

Regards from Perth

Derek

[Andrew Hughes]

So you have a Dj 20 ? That's a nice machine. See if you can get a full end to end cut with that board on edge. Just pass it along don't push anywhere. Look at the contact it make with the table before and after the cut this will tell a lot.

[johnny means]

The board you show in the photo doesn't tell a whole lot. On a perfectly tuned jointer with perfect technique, many boards would look like that after a single pass. The fact that it cut on both ends says to me that your jointer appears to be set up at least close to where it should be.

[johnny means]

Btw, on bowed boards you should be removing material from the middle if running smile side up, or both ends if running frown side down.

[john schnyderite]

It appears to be taking material from the right area, but with a lot of material coming off the front and minimal off the back, it seems like the board would be a wedge by the time 1 face is flat.

[Mark Hennebury]

Lower the outfeed table.

[john schnyderite]

I think I might have found the issue.

it appears the infeed table is lower than the cutterhead unless i bring the infeed very close to the outfeed table height. When I was setting the jointer up, I originally set it up higher, but the guard was rubbing on the outfeed table and the blades seemed to protrude from the cutterhead more than they should, so dropped it back down a bit.

As of right now, the knives are less than .001 higher than my cutterhead, so I'm afraid just adjusting the outfeed won't really solve my issue. Looks like I may need to adjust my blades to be higher again too.





Lower the outfeed table.

[johnny means]

The infeed table has to be lower than the cutterhead, that's how jointers work.

[Mark Hennebury]

I think I might have found the issue.

it appears the infeed table is lower than the cutterhead unless i bring the infeed very close to the outfeed table height. When I was setting the jointer up, I originally set it up higher, but the guard was rubbing on the outfeed table and the blades seemed to protrude from the cutterhead more than they should, so dropped it back down a bit.

As of right now, the knives are less than .001 higher than my cutterhead, so I'm afraid just adjusting the outfeed won't really solve my issue. Looks like I may need to adjust my blades to be higher again too.

There are thousands of shop manuals, pictures, video tutorials of setting up a jointer.
You should probably take some time to do some studying so that you understand the machine and its basic setup, then if you are having problems ask for help, otherwise any advice wont be of any help to you.


385473

[David J Blackburn]

Late to the game maybe, but based on those pictures, nothing seems to be wrong. In the 4th picture, the board is resting flat on the jointer bed through the first 1/3 or so, then raised, then touching again only at the very back. That's the exact pattern you see it cutting at. I'd expect that after a few more passes (the raised part isn't that high off the bed), you'll get full length cuts.

[Carlos Alvarez]

I'd start with a very careful, obsessive machine adjustment. I do this on occasion, and the results are always excellent. The first time I *really* obsessively adjusted the jointer, the results were pretty amazing. Find some perfect engineer's squares, a flashlight, some feeler gauges, and use any of the online guides along with the owner's manual to achieve perfect alignment in every direction. I have all my tools tuned to within 1/256th in any direction, which "everyone" says isn't necessary yet the results speak for themselves.

[Bill Space]

Lower the outfeed table.

Several people have recommended that the OP’s outfeed table be lowered. Not a simple task on a parallelogram jointer. Four corners need to be adjusted exactly the same amount to keep the outfeed table in a plane parallel to where it started. This is a much simpler task on a jointer with dovetail ways, only one screw needs turned. The OP’s jointer is a parallelogram jointer.

EDIT: MY ERROR. The exit table can indeed be lowered simply on the parallelogram jointer. Been out of the country and away from my shop for month...have to go back and relearn my machines I guess...

A tilted infeed table can also cause tapered results.

In in my view, adjustments need to be referenced to something. Of course it may be possible to misadjust one thing to compensate for another misadjustment, and end up with results you find satisfactory.

In my case, with my parallelogram jointer, I have concluded I need to set the outfeed table at the height of the cutting knives, so it is at the same height as the knives at both edges. Then the outfeed table/knife edge combination becomes the reference to which other adjustments are made and measured. The relationship between the outfeed table and the knives is Locked in place. Other things are set with respect to the outfeed table/knives. Measurements are referenced back to them.

Since the cutting edges of the knives are in the same plane as the outfeed table, the output table alone can serve as the reference point for settings/measurements.

At at the end of the day, with a parrallogram jointer, the infeed table should be adjusted to be coplaner with the outfeed table(after the outfield table is positioned properly with respect to the knives). Once this is accomplished one can move on to technique, which may be as important to jointer results as machine set up.

Another’s experience/opinion for what it is worth...:D

[glenn bradley]

My first thought was that the board was longer than the beds and you were seeing the result of poor support. The pics clarified that to not be the case. Thanks for posting them.


Several people have recommended that the OP’s outfeed table be lowered. Not a simple task on a parallelogram jointer. Four corners need to be adjusted exactly the same amount to keep the outfeed table in a plane parallel to where it started. This is a much simpler task on a jointer with dovetail ways, only one screw needs turned. The OP’s jointer is a parallelogram jointer.

My p-bed machine just has a lever for the outfeed table height adjustment. I would be surprised to find one that didn't but, it sounds like they're out there. Probably just my limited exposure. Changing the height via the bed leveling cams would indeed be a pain and I would advise against it. IMHO, Derek was correct when he warned to move to table alignment adjustments only when you have exhausted all other possibilities. Forums have plenty of example of folks who made themselves a ton of work by diving right in to table alignment as the fix for their jointer issues. There are definitely times for that but generally, reported jointer issues are technique related.

The board in the pic looks normal to me for a few jointer passes on a bowed board being worked concave surface down. This is the recommended orientation for that irregularity in all the creditable jointer how-to's I've seen. Any irregular surface needs to be jointed until completely flat. There will be stock removal proportional to the deviation. On severely humped boards I will hand-plane the ends off a bit before jointing. Once you are better acquainted with the machine, starting in the middle where the board does not touch and shaving off each end a bit on the jointer is also a common technique.

[jack forsberg]

Several people have recommended that the OP’s outfeed table be lowered. Not a simple task on a parallelogram jointer. Four corners need to be adjusted exactly the same amount to keep the outfeed table in a plane parallel to where it started. This is a much simpler task on a jointer with dovetail ways, only one screw needs turned. The OP’s jointer is a parallelogram jointer.

A tilted infeed table can also cause tapered results.

In in my view, adjustments need to be referenced to something. Of course it may be possible to misadjust one thing to compensate for another misadjustment, and end up with results you find satisfactory.

In my case, with my parallelogram jointer, I have concluded I need to set the outfeed table at the height of the cutting knives, so it is at the same height as the knives at both edges. Then the outfeed table/knife edge combination becomes the reference to which other adjustments are made and measured. The relationship between the outfeed table and the knives is Locked in place. Other things are set with respect to the outfeed table/knives. Measurements are referenced back to them.

Since the cutting edges of the knives are in the same plane as the outfeed table, the output table alone can serve as the reference point for settings/measurements.

At at the end of the day, with a parrallogram jointer, the infeed table should be adjusted to be coplaner with the outfeed table(after the outfield table is positioned properly with respect to the knives). Once this is accomplished one can move on to technique, which may be as important to jointer results as machine set up.

Another’s experience/opinion for what it is worth...:D

Not to beat a dead horse but the outfeed table should be lower than the cutting Circle of the knives by the amount of the scallops ( knife marks ) it makes while cutting . This is simply because it isn’t the depth of the cut in the Marks that rides and reference the out feed table it is the peak of the scallops knife marks made by the cutter block. Generally .0015” lower . This should always be the first thing try a this is the most common remedy to this problem or as a technique to induce a spring joint. you’ll have to forgive me but I do not understand why you cannot adjust the height on a parallelogram jointer. It’s mechanism is parallel.

[Matthew Hills]

I ran a smaller board though which had a bow. I ran it 'frown'-wise. Here are some photos of the result after 3-4 small passes. I focused pressure only on outfeed side while running though. It seems to take more material on the side that is run through first.

is your board deforming under your pressure? (place it on a bench and push on it and see if the frown goes away) This could explain why the tail is not cutting normally.

I sometimes find it useful to do the opposite -- use modest pressure and focus the cutting in just the regions where I know the board is high (e.g., at the front or back). At this point, you may want to do more of that on the back side until the board sits pretty flat on your bench. Once the board has better support, you can switch to the pressure-on-outfeed technique that uses the outfeed reference surface.

(ps--twist is much more annoying and really requires some practice to work through... or a handy burn pile)

Matt

[Bill Space]

Jack,

I went back and edited my post to correct for the misstatement I made about the height adjustability of the exit table on a parallelogram jointer. It is indeed easily adjustable.

Your comment on the need to account for the depth of the scallops the knives make is enlightening. I do not recall seeing that mentioned previously and it makes complete sense. This is the first time I have seen a concrete reason given for lowering the exit table below the apex of the cutters (which I have seen recommended many times in many threads).

Thanks for the insight!

Bill

[john schnyderite]

Thanks so much for all the feedback. I ran that same board through a few more passes and there is now a bit of a belly in the middle it seems, as i can see plenty of light on either side of the board on the end opposite where I put pressure on the straight edge. This seems to be because more material is being taken off the leading edge of the board. nothing is being taken off the back now unless i put pressure on the infeed side when running through. There is definitely something wrong with my jointer setup.

I set the blades slightly higher than my outfeed table (less than .001 higher). I used a straight edge and feeler gauges to set the infeed table coplanar with the outfeed (though I have moved both the infeed and outfeed table up and down since setting that up, so maybe I should double check that it is still in line. At the time I'd estimate all 4 corners were within .001.

I'm losing hope that I'll ever get this thing running right =/ Is anyone located in NJ who wants to help a fellow woodworker out?

[Jim Morgan]

What you have described is a classic symptom of having the outfeed table set too high. An old-time method for setting knives was to set a board on the outfeed table and rotate the cutterhead by hand - each knife should move the board by about 1/8". As several others have suggested repeatedly, set the outfeed a little lower.

[Bill Space]

John,

First of all don’t give up. You will eventually resolve the issue.

Jack’s advice is rock solid. Set the outfeed table slightly lower than the blade tips at their apex and lock the setting there. The reason to do this is because the scallops caused by each blade cut leaves a little protrusion that points downward and the exit table must be lowered slightly to allow the workpiece to slide perfectly along it. I only came to understand this due to Jack’s comment above.

Next, verify that your infeed table is indeed coplaner with the outfeed table. Actually you may have to do this first, before finally setting the final position of the outfeed table.

Imagine that your infeed table were low on the input side(the end farthest from the cutting head). As you start to joint the piece, it will tend to pass the cutters and rise above the outfeed table. Then when you push down on the portion that is above the outfeed table, it will tend to pivot and raise the tail end off the infeed table to a point where the cutters may no longer take a bite. So you can get little or almost no material removed off the tail end. If this were the case, the solution would be to raise the end of the infeed table somewhat.

In my particular case I have noticed a situation similar to yours, where more material is removed on the leading edge. For me this has not been an issue as with 4/4 stock I can still joint one face and have enough material left to easily produce 3/4+ material. But I too want to correct this issue.

Some have claimed that tapering on the jointer is inherent to the tool, but I don’t subscribe to this idea... One workaround I have seen suggested is to alternate feed directions of the workpiece, so that you take more off each end on alternate passes. This may work but does not feel right, at least to me.

Anyway, don’t give up. Take a break and come back to the issue with a fresh mind in a few days. There are many people getting satisfactory results from their jointers, which is proof that you can too.

Edit: In my mind an infeed table that is high on the far end will result in the same issue, but the geometry is different. Solution is the same though, make the infeed table coplaner with the outfeed table.

Bill

[Mark Hennebury]

Thanks so much for all the feedback. I ran that same board through a few more passes and there is now a bit of a belly in the middle it seems, as i can see plenty of light on either side of the board on the end opposite where I put pressure on the straight edge. This seems to be because more material is being taken off the leading edge of the board. nothing is being taken off the back now unless i put pressure on the infeed side when running through. There is definitely something wrong with my jointer setup.

I set the blades slightly higher than my outfeed table (less than .001 higher). I used a straight edge and feeler gauges to set the infeed table coplanar with the outfeed (though I have moved both the infeed and outfeed table up and down since setting that up, so maybe I should double check that it is still in line. At the time I'd estimate all 4 corners were within .001.

I'm losing hope that I'll ever get this thing running right =/ Is anyone located in NJ who wants to help a fellow woodworker out?

Did you look at the photo that i posted? That's how jointer is set up. The amount of cut is determined by how much you lower the infeed table. Set the blade protrusion correctly according to the manual . set the outfeed table at or just below the TDC of the cutting circle. bring the infeed table up level wit the outfeed table and you wont cut anything, then lower the infeed table to the depth that you wish to cut. Lower the infeed 1/32" you will cut 1/32" of wood, lower the infeed 1/16" , you will cut 1/16" of wood etc..
385612385613

[Andrew Hughes]

Be sure your adjusting the outfeed to the highest knife. Hope your working out the bugs with a fresh sharp edge.
Good luck

[Mel Fulks]

The slightly open ends with two edges together is kinda the standard position for many commercial shops. It is preferred by many over the climbing and 'running out of material' at the end of the cut produced by the "too high" table. Few find adjusting a jointer easy or enjoyable, that is why every problem has a standard "good enough" ...so much easier that accurate! An outfeed table that is adjusted by a stick is more difficult to get right than one with a wheel. The wheels can be calibrated ,then you know exactly how much you are moving it. That is why I know that climbing is caused by a table 1
and 1/2 thousandths too high ,not an easy adjustment to make on machines with the "stick". The calibrated wheel lets you
easily adjust the table. If there is a nick at the middle of the table I can drop it to face a wide board ,then after planing it
raise the table to get accurate closed end edge jointing.

[john schnyderite]

Thanks for the encouragement. i'll take a look at whether my tables are coplanar again or they've moved out of sync with other adjustments to the tables. Hopefully that is my issue.

By 'slightly lower than the blade tips', can you give me a number to shoot for? As I mentioned, outfeed is currently set half thousand to .001" lower than the highest point of the blades according to my digital gauge. Is that an appropriate amount? I hear many saying to lower the outfeed table, but no input on how low it should be.



John,

First of all don’t give up. You will eventually resolve the issue.

Jack’s advice is rock solid. Set the outfeed table slightly lower than the blade tips at their apex and lock the setting there. The reason to do this is because the scallops caused by each blade cut leaves a little protrusion that points downward and the exit table must be lowered slightly to allow the workpiece to slide perfectly along it. I only came to understand this due to Jack’s comment above.

Next, verify that your infeed table is indeed coplaner with the outfeed table. Actually you may have to do this first, before finally setting the final position of the outfeed table.

Imagine that your infeed table were low on the input side(the end farthest from the cutting head). As you start to joint the piece, it will tend to pass the cutters and rise above the outfeed table. Then when you push down on the portion that is above the outfeed table, it will tend to pivot and raise the tail end off the infeed table to a point where the cutters may no longer take a bite. So you can get little or almost no material removed off the tail end. If this were the case, the solution would be to raise the end of the infeed table somewhat.

In my particular case I have noticed a situation similar to yours, where more material is removed on the leading edge. For me this has not been an issue as with 4/4 stock I can still joint one face and have enough material left to easily produce 3/4+ material. But I too want to correct this issue.

Some have claimed that tapering on the jointer is inherent to the tool, but I don’t subscribe to this idea... One workaround I have seen suggested is to alternate feed directions of the workpiece, so that you take more off each end on alternate passes. This may work but does not feel right, at least to me.

Anyway, don’t give up. Take a break and come back to the issue with a fresh mind in a few days. There are many people getting satisfactory results from their jointers, which is proof that you can too.

Edit: In my mind an infeed table that is high on the far end will result in the same issue, but the geometry is different. Solution is the same though, make the infeed table coplaner with the outfeed table.

Bill

[johnny means]

I'd like to see someone do the actual math on the scallop depth idea. The flaw in that idea is the presumption that the user is feeding fast enough to leave each peak intact before making the next cut.

[Mel Fulks]

John ,the height has been addressed. They need to be the same. But it is easier and more practical to start with outfeed too low and raise it until it is exact. That is the way I season my food .....too much trouble to weigh it!!! As I said just a few minutes ago many prefer to avoid "climbing " by just keeping the outfeed table a little too low. But that makes joints that are open at the ends. A jointer needs adjustment according to present use and knife condition. That is why the front tabe is adjustable.

[Mark Hennebury]

Thanks for the encouragement. i'll take a look at whether my tables are coplanar again or they've moved out of sync with other adjustments to the tables. Hopefully that is my issue.

By 'slightly lower than the blade tips', can you give me a number to shoot for? As I mentioned, outfeed is currently set half thousand to .001" lower than the highest point of the blades according to my digital gauge. Is that an appropriate amount? I hear many saying to lower the outfeed table, but no input on how low it should be.


Post a photo of your machine showing the cutterhead, knife protrusion and tables as in the photo i have posted please, that might clear a lot up.

[Warren Lake]

I set my knives .050 above the head consistent to .0005. My head is parallel to the outfeed table. Just like Mel I drop the out feed, I snipe and bring it back up and test for now bow or gap. I stopped on the wood block thing 30 years ago. few test cuts and its dialed in, as you use it in some time it will change, for a spring joint raise a tiny bit and test. This stuff is assuming the machine is set up right and your technique is right and you understand the material.

[jack forsberg]

here is how i set the out feed table after knifes are set. so easy




https://www.youtube.com/watch?v=T-w7N2U9slA

if you want to see how i set and stone all the knifes to a perfect cutting circle dead nuts to the rear table within one 10th of a thou see part one

https://www.youtube.com/watch?v=FdLJPLJdY2Q

[john schnyderite]

Thanks for that Jack. I did lower my outfeed table by another .003, and checked my tables for coplanar. I found the infeed side furthest from the knives to be a few thousands low. I adjusted and made a couple test passes. Definitely getting more contact on the trailing edge of the board. Still have a bit of a belly towards the middle of the board that i ran. Not sure if its me, the machine or it just needs a few more passes to straighten out. I'm going to check the blade height vs outfeed using the technique in your video and see how close I am and evaluate from there.




here is how i set the out feed table after knifes are set. so easy




https://www.youtube.com/watch?v=T-w7N2U9slA

if you want to see how i set and stone all the knifes to a perfect cutting circle dead nuts to the rear table within one 10th of a thou see part one

https://www.youtube.com/watch?v=FdLJPLJdY2Q

[Steve Demuth]

I ran a smaller board though which had a bow. I ran it 'frown'-wise. Here are some photos of the result after 3-4 small passes. I focused pressure only on outfeed side while running though. It seems to take more material on the side that is run through first. The front of the board is already .1" thinner than the back side of the board though the bow makes it appear that material should be coming off the back too. I noticed this also when running longer boards.

https://photos.app.goo.gl/zTyvAxRbQGkgjmdt2

John,

It's hard to be sure without seeing the board before the first 3-4 passes, but there's nothing in those photos that very strongly suggests you have a problem. Given the very nasty knot on the trailing end of the board, it's not at all unlikely that most of the bow distortion in the board was at that end, and you're seeing the expected result. Before you adjust anything, I'd take a board that is already straight on one edge and determine if you get uniform stock removal when you joint that edge. That's easy to do - scribe a line 1/8" or so from the straight edge, and then joint the straight edge using shallow (< 1/16") cuts, looking at how the cut approaches your scribed line over several passes. If the edge approaches the scribed line uniformly, you're good. If it does not - if the leading edge approaches more quickly, then you probably need to lower the outfeed table a thousandth or so, or (unlikely, and don't go into fixing this unless you have the mechanical skills and tools to do so, because the possibility of making things worse are considerable) your tables are not coplanar.

[Andrew Hughes]

Im thinking the Op has a Dj20 that's had its cams fondled or it's been lifted and handled from the ends of the tables.
Until the tables are set back to coplaner there not much help or table up and down advise that's going to work.
I also think Jacks knife sharpening video is silly and pointless.:cool:
I also see a precision straight edge in your future.;)
Good luck

[Mel Fulks]

Andrew, Enjoyed your movie,but don't think those adjustment levers are much good for moving something a thousandth
at a time. But it might be useful for moving rubble off earth quake victims.

[Andrew Hughes]

Andrew, Enjoyed your movie,but don't think those adjustment levers are much good for moving something a thousandth
at a time. But it might be useful for moving rubble off earth quake victims.
I hear ya Mel. The levers would be a waste of time and should be removed once the knifes are set for a perfect cut. So some clown doesn't change the setting.
The Dj 20 has adjustable cams or bushing to level the tables.If they are good and flat it's worth the time and set them right.
Good night Sir :)

[jack forsberg]

I also think Jacks knife sharpening video is silly and pointless.:cool:

Good luck
I would agree not something needed now a days . much faster for me to do this than change out the knifes as this is my edge joint planer /jointer . :cool:

[David J Blackburn]

Yes, this. I said the same thing the other day, but I wouldn't fiddle with the settings based on what's in those pictures. You're likely to make things work. You have a board with a lot of cupping at the back end, and when you run it over the jointer, it's cutting in the other parts, and not there.

Joint something already flat and see if it takes even cuts. It doesn't even have to be perfect- as Steve said, just find a board that lays flat on flat surface, run it over the jointer and see if it stays that way.

[Andrew Hughes]

Yes, this. I said the same thing the other day, but I wouldn't fiddle with the settings based on what's in those pictures. You're likely to make things work. You have a board with a lot of cupping at the back end, and when you run it over the jointer, it's cutting in the other parts, and not there.

Joint something already flat and see if it takes even cuts. It doesn't even have to be perfect- as Steve said, just find a board that lays flat on flat surface, run it over the jointer and see if it stays that way.

David Blackburn the furniture maker? We met at the Oc fair sometime ago I'm also a big fan of your work. Just wanted to say hi and that I'm still plugging along.:)

[Steve Demuth]

I'd like to see someone do the actual math on the scallop depth idea. The flaw in that idea is the presumption that the user is feeding fast enough to leave each peak intact before making the next cut.

There are some approximations in this, but nothing that invalidates the point.

A typical small jointer, like the Powermatic 54a has a 3" diameter cutting head running at 6000 rpm, or 18000 cuts per minute. If you feed stock at 18 feet per minute (a reasonably brisk hand feet rate), you're making 1000 cuts per foot. The arc of each cut is therefore .012" - 12 thousandths of an inch - wide. A little trigonometry will will tell you the depth of the arc is just over .00001" - one hundred thousandths of an inch. To get a .0015 - one and a half thousands - depth of arc, you'd have to move the board fast enough to get .19" per cut width - roughly 3/16" - which at 18000 cuts per minute is 285 ft per minute. That is, you'd have to run a a 4' board through your jointer in under 1 second. Power feeders can do that. Humans probably can't, and certainly typically don't.

I corrected an earlier arithmetic mistake in which I indicated the .19" per cut width equated to 135 fpm.

[jack forsberg]

There are some approximations in this, but nothing that invalidates the point.

A typical small jointer, like the Powermatic 54a has a 3" diameter cutting head running at 6000 rpm, or 18000 cuts per minute. If you feed stock at 18 feet per minute (a reasonably brisk hand feet rate), you're making 1000 cuts per foot. The arc of each cut is therefore .012" - 12 thousandths of an inch - wide. A little trigonometry will will tell you the depth of the arc is just over .00001" - one hundred thousandths of an inch. To get a .0015 - one and a half thousands - depth of arc, you'd have to move the board fast enough to get .19" per cut width - roughly 3/16" - which at 18000 cuts per minute is 285 ft per minute. That is, you'd have to run a a 4' board through your jointer in under 1 second. Power feeders can do that. Humans probably can't, and certainly typically don't.

I corrected an earlier arithmetic mistake in which I indicated the .19" per cut width equated to 135 fpm.

UnLess the knives are jointed you can only assume a one knife cut from the head . At 30 feet feed rate it would be less than 17 kmpi

https://www.mr-moulding-knives.com/information/moulding-knife-marks

[Jim Morgan]

Isn't it also possible that there may be some amount of compression/springback with each cut? This would vary by species and be more pronounced with dull knives. In any event, this would suggest that the outfeed table should be set slightly below TDC to compensate.

[Steve Demuth]

UnLess the knives are jointed you can only assume a one knife cut from the head . At 30 feet feed rate it would be less than 17 kmpi

https://www.mr-moulding-knives.com/information/moulding-knife-marks

With respect, Jack, I can put a machinists' dial indicator on my jointer after I set the blades and verify that I've got circular uniformity to within less than half a thousandth. No jointing necessary. The fact that my knives dull reasonably uniformly further proves that they are all cutting.

But even if you are running an effectively one-knife cutter head, the math is still not going to justify the theory that the outfeed table offset below the knife height corresponds to the scallop depth. When you adjust the math above, you'll have 28 cuts per inch, and you're still going to get a scallop barely .0001 - one ten thousandth - deep. And that's pushing the board through at 18 fpm. A hobbiest using a small jointer looking for the best finish or glue joint will probably run at half that speed.

[Mel Fulks]

As I wrote earlier, most jointers I've seen in commercial shops DO have the outfeed tables set slightly below TDC. But it serves no purpose beyond making sure the material does not climb and leave some of the edge unjointed. When the jointing is being done to make a surface fit for edge gluing the ends will be open....making an unfit ....misfit,likely to pop open after being glued.

[Matt Mattingley]

With respect, Jack, I can put a machinists' dial indicator on my jointer after I set the blades and verify that I've got circular uniformity to within less than half a thousandth. No jointing necessary. The fact that my knives dull reasonably uniformly further proves that they are all cutting.

But even if you are running an effectively one-knife cutter head, the math is still not going to justify the theory that the outfeed table offset below the knife height corresponds to the scallop depth. When you adjust the math above, you'll have 28 cuts per inch, and you're still going to get a scallop barely .0001 - one ten thousandth - deep. And that's pushing the board through at 18 fpm. A hobbiest using a small jointer looking for the best finish or glue joint will probably run at half that speed.

Steve, what is the diameter of your head, what is the diameter of your cutting Circle, what kind of knives are using? What is your 90° attack angle of your knife? What is your knife material made out of and Rockwell value? Are your knives Straight, skewed or helical and what are your in feed and outfeed table lengths? Each machine manufacture considers these important values.

First, most good bearings have a unloaded lash +- .0001. As soon as you apply a workload to it, there goes that lash.

My outfeed table is set to 0.0005 below the knife circle. I have a helical head and I use carbide inserts with 78ish Rockwell.(Rockwell value is a test hardness of the cutting material). Carbide dulls quite a bit slower than HSS, A2, D2 & M2. (there is the difference between carbide inserts and carbide knives and there is also a difference between insert manufacturing heads)I can send 1000 feet of IPE and it simply grinds my cutting circle down to 0.0003 above the outfeed table. I still have plenty of horse power to keep cutting and the inserts are still razor sharp. I have about 50 inserts in my head that run $6 apiece. But, that is $1.50 per cutting edge or $75 per full rotation. It is only A two knife head 12 inches jointer.

A 3 inch radius 0.0002 worn will still cut paper razor sharp.

Most people like to do indicating with brand new razor sharp blades. Most of the time there is a grinding bur that should be folded over with two or three swipes with a 2000 grit stone (you can actually even use a Real copper penny).

I hope you got your pennies worth with this post.

[jack forsberg]

Steve, what is the diameter of your head, what is the diameter of your cutting Circle, what kind of knives are using? What is your 90° attack angle of your knife? What is your knife material made out of and Rockwell value? Are your knives Straight, skewed or helical and what are your in feed and outfeed table lengths? Each machine manufacture considers these important values.

First, most good bearings have a unloaded lash +- .0001. As soon as you apply a workload to it, there goes that lash.

My outfeed table is set to 0.0005 below the knife circle. I have a helical head and I use carbide inserts with 78ish Rockwell.(Rockwell value is a test hardness of the cutting material). Carbide dulls quite a bit slower than HSS, A2, D2 & M2. (there is the difference between carbide inserts and carbide knives and there is also a difference between insert manufacturing heads)I can send 1000 feet of IPE and it simply grinds my cutting circle down to 0.0003 above the outfeed table. I still have plenty of horse power to keep cutting and the inserts are still razor sharp. I have about 50 inserts in my head that run $6 apiece. But, that is $1.50 per cutting edge or $75 per full rotation. It is only A two knife head 12 inches jointer.

A 3 inch radius 0.0002 worn will still cut paper razor sharp.

Most people like to do indicating with brand new razor sharp blades. Most of the time there is a grinding bur that should be folded over with two or three swipes with a 2000 grit stone (you can actually even use a Real copper penny).

I hope you got your pennies worth with this post.

lots to consider there .

its not like you can not get a good cut with one knife .


https://www.youtube.com/watch?v=0lB21cGbugY

[jack forsberg]

With respect, Jack, I can put a machinists' dial indicator on my jointer after I set the blades and verify that I've got circular uniformity to within less than half a thousandth. No jointing necessary. The fact that my knives dull reasonably uniformly further proves that they are all cutting.

But even if you are running an effectively one-knife cutter head, the math is still not going to justify the theory that the outfeed table offset below the knife height corresponds to the scallop depth. When you adjust the math above, you'll have 28 cuts per inch, and you're still going to get a scallop barely .0001 - one ten thousandth - deep. And that's pushing the board through at 18 fpm. A hobbiest using a small jointer looking for the best finish or glue joint will probably run at half that speed.

as others have said you can get this simple machine to work in a number of ways . i never have had good results with the Rear table at TDC. just sharing what works for me


https://www.youtube.com/watch?v=coz5wpIHchk

[Steve Demuth]

Matt,

Of course all the things you ask and then assert are relevant to the performance of a jointer. And, I was in no way arguing that you don't want to set the outfeed below the cutting circle of the head. You should, and If you don't, you'll generally get a tapered a cut on most machines, as many posters here, including myself, have pointed out. All I was saying in answering Johnny's question about someone "doing the math" on the scallops is that the depth of the scallops from even a small cutter head at hand feed speeds, is indeed very shallow - much less than the outfeed clearance you want for a uniform cut on a hand fed machine.

My answer to Jack was simply to say that this is true, whether or not you joint your knives. I don't, because I don't have to, and because jointing produces an inferior cutting edge. A jointed head, unless you start out with nearly perfect concentricity and do minimal material removal as a result, easily ends up with one or more knives having an excessive (to my likes) land width, with the result that at hand feed speeds, you burnish your cuts excessively.

Since I am in the shop mostly because I love being in the shop and working with the machines - no deadlines, production targets or particular budget restrictions - I prefer to spend a bit extra time getting very sharp knives, and setting them precisely. I in no way suggest that I'd take the same approach if I were in any sort of production.

[Steve Demuth]

as others have said you can get this simple machine to work in a number of ways . i never have had good results with the Rear table at TDC. just sharing what works for me


Jack,

I didn't say you don't want clearance between the cutting circle and the outfeed height. Quite the opposite - I agreed in other responses that you do. I was just pointing out that the depth of the scallops per se, is not the reason, and in my response to you later that unjointed cutters aren't an explanation.
I suspect, but have not done the work to completely justify my suspicion, that compression of the wood at the cutter head and leading edge of the outfeed table, and subsequent relaxation down table, is the biggest factor driving the need for clearance. If so, then jointed knives if anything increase the need. Jointed knives are certainly going to pound the wood at the lands more than unjointed.

[jack forsberg]

Steve if done properly stoning is not an inferior edge . its not a way to correct knife setting its a way of maintaining the edge and surface finish . the knifes i set are as you say within 10th of a thou and you my have a good point about the wood .


see here how careful i set fresh knifes
https://www.youtube.com/watch?v=k87WRWWFV_s

this video is after careful setting and the stoning


https://www.youtube.com/watch?v=vN__T5s9r1o

setting is now with the Wadkin setting stand i just rebuilt

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https://www.youtube.com/watch?v=8niha1LAUog

how is the cut

https://www.youtube.com/watch?v=O-ItjKtCFIg

[Brian Holcombe]

I’m curious if the boards are actually flat when you surface them, if not that would provide insight depending on the shape they make.

Apologies if this was already covered.

[Joe Calhoon]

Its not rocket science. Jointer setting requires tables flat and coplanar with knives in head at same cutting circle. The level of difficulty to achieve this depends a lot on the build quality of machine. Insert heads such as Tersa or spiral make this easier.

The out feed table should be slightly lower. I'm not a machinist but on the jointer a well planed workpiece should move 2mm + or - with each rotation.
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I do not know the why of this but it is the same for hand and mechanical fed machines. Shapers with split fences, profilers and molders the same. If the out feed table or fence is not set slightly below the cutting circle you will get snipe or wedges.
Our T90 straightening moulder has a magnetic setting device that works good on the side head but a piece of wood works about as well.
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[Mel Fulks]

I don't dispute Joe's table slightly lower advice, especially since I just raise the table,test fit two just jointed pieces ....repeat as needed. But most I've seen and fixed were too low to make good glue at all points contact. I still say that for those lucky enough to have a jointer with wheel adjustment, you should just calibrate the wheel.
To do that I mark current position on wheel edge and machine body. Get infeed table level with outfeed table. Give wheel one full turn . Measure how much out feed table moved up . Mark and file marks on edge of wheel. Add a sheet metal pointer. Marks end up usually 5/16ths to 3/8 ths apart. Marks represent about two thousandths. That simple modification means : a knick in knives will not make work "climb". Hollow glue joints are easy. Straight pieces are easy.