depth of jointer cut from a different prospective

[tablesawtom]

I started to respond to a different persons post but I didn't want to steel another's post so I started this one.

If you run a cupped board through a planner it will come out cupped because of the pressure rollers. The same holds true with a jointer.  A cupped board is not as critical on a jointer as a  bowed or twisted boards is. If you are taking a heavier cut more downward force has to be applied as well as force to get the board to move forward accosted the cutter knives. More force a crossed the cutter usually ends up more downward force is applied the the board. So bowed in bowed out. It may be flat accosted but not end to end.

I know everyone is choosing to do carbide cutter heads but carbide, no matter what, is not as sharp as high speed, so more force is needed to move the workpiece a crossed the cutter head. One can produce all kinds of arguments defending inserted cutter heads but the fact remains more force is needed to move the board accosted the cutter head. And that force is compounded by the depth of cut.

So weather or not you like it your hand do the same thing on the jointer as the pressure rollers do on the planner. Depending on what size  of jointer you have take a piece of wood nearly as wide and is the length of the infeed table. Make sure the the board is bowed and take a cut 1/16 deep and when it is on the outfeed table let it set (keeping your hands off so you can't push down) check and see it is is flat by using a feeler gauge.

Please, please do not get me wrong. there are trade offs both pros and cons  between high speed cutters and  carbide inserted cutters. I did a lot of thinking, gathered a lot of information. tried out a few of my friends jointers That had inserted cutter heads. and have chosen to stay with HS steel knives because of the same reason a bowed board into a planner a bowed board out of a planner.

My disclaimer is I am on a fixed income and because of my reasoning I can nor justify the added expense to change cutter heads. If I could justify it I would change cutter heads in an instant. 

So based on what I have written I have my jointer set for a 1/64th of an inch depth of cut. (.016). I have an eight inch jointer and I can cut an eight inch wide board the length of my infeed table ( somehere around 35 inches in length ) and I can cut it with one hand.  

I know that 4 cuts equals 1/16 so that allows me to keep track as to where I am when it come to thickness.

Most 4 /4ths material come from the saw mill skipped planed around 15/16ths ( .9375) to 7/8ths (.875)  if I were to take 1/16 depth  of cut and it didn't clean up and I needed to take another cut I would have very little or nothing to take off if I needed to take another cut. If I needed to take 6 cuts  at 1/64 to get it flat I would still have material left for the planner.

If your mind is made up about depth of cut please do not bother to respond because several of you have already responded on a different post. If you wish to respond to defend the inserted cutter head please do not. This post is about cutting pressures verses depth of cut, not cutter heads, which have been discussed over and over again. 

BUT, if you wish to keep an open mind and really inspect your cutting practices and inspect your actual results, I am all in. I would be interested in how you deal with the cutting pressures on an inserted cutter. Do you know for sure if you beards are flat accessed the jointer or are you just assuming they ate because you cut off 1/16 so they have to be.

I am going to take some pictures of what I use to feed on a jointer. And just so you know somewhat of where I am coming from, I had a broken little finger on my right hand and I was using the jointer which I shouldn't have been doing and I managed to cut off the tip off my first finger. So now it is gone to just below the finger nail. I now can not pick up a pencell from off the floor using that finger. I had to relearn how to tie my shoe using a different finger.

I have evaluated and reevaluated the incident and I might still have my finger tip if less pressure was involved, not to mention better push blocks.\

Tom

[Philip1231]

I've had my jointers set to 1/64" for years: seems to work quite well for me.

[KyleD]

I have a 15 year old Delta DJ20 that I installed an insert head in about 8 years ago so I have experience with both heads. It is a fact that one has to push down a little harder with the insert head. Even with the need to push harder I have no problems with taking cup out of boards. A planer has a roller that always pushes down with the same force and always across the entire board. This means cupped boards that are at all flexible will come out cupped. I think the reason why I do not have the same problem with removing cup on an insert jointer is because instead of a dumb roller that treats every board the same there is a brain behind the jointer push down system. 
When I come to a cupped board I lay it down and push to see how flexible it feels. If I am worried about pushing the cup out while feeding I push on the edges of the board on the in-feed side and sometimes will deepen the cut so I can carefully feed the first part of the board and then push down on the outfield table more than the in-feed. Also the disadvantage of harder pushing on an insert head disappears rather quickly if straight knives are not changed quickly when they start to get dull which they tend to do regularly.

[barryvabeach]

Some suggest that when running a cupped board on a jointer, you do it with the convex side down, concave side up, and take just short passes from the middle  ( or wherever the cup is worse ) and use a jointer pushblock that has an end catch.  That reduces the problem Tom mentioned.  Once you get it close, you then take full length passes, and when one side is flat, you run the other side through the planner.

[Tapper]

I've flattened many a cupped and twisted board on my 8" jointer, 1/32" at a time. The Byrd head helps immensely. One should never run a board through a planer without at least one flat side or a jig to provide a flat surface. I've crosscut many boards over the years that were too cupped or twisted to be able to be flattened successfully on the jointer. Crosscutting can take out the majority of the twist or cup and make at least a portion of the board salvageable.

Doug

[tablesawtom]

Yes, I know all about taking the cup out of a board by running it cup side down. Taking the cup out is easy. It is taking the bow out that is the hard part. If the board is bowed, then hand pressure alone will flatten the board as it crosses the cutter head but will spring back when the cut is completed. 

As someone who agrees with me  in this post, that it takes more force when using an inserted cutter head to take a cut and the deeper the cut the more force it takes. An example would be walking a mile and running a mile. Who will be winded first. I am talking amount of effort applied.

Again, I have used a straight knived, 8 inch jointer for over 35 years. I sharpen my own knives on a surface grinder. I am 76 years old and on a fixed income, and I just don't see a reason to spend the kind of money it would take for me to do it.

I did try out an inserted head jointer a few years ago and the difference in feed pressure really stood out to me. Actually that alone helped me to decided that the inserted cutter head was not for me. Please do not get me wrong there are a lot of pro's to an inserted cutter head.  In a prefect world I would like to have one of each. Again application. This post is about getting a board flat. Again taking the cup out is easy. I do not think one can put enough downward pressure on a 8 inch wide board to flatten the cup out so it can spring back and move the board a crossed the bed of the jointer at the same time. It is getting the board truly flat that is more difficult and the deeper the depth of cut the harder it will be. 

I know from a lot of experience in cutting both wood and metal that more cuts at a lighter depth does a better job than one deep cut. Even my knives stay sharper longer.  Yes it will take a little longer but you are doing it foe fun. Try a lighter cut a few times and see if you do not get better cuts. But if you do please be honest with your evaluation. If you have allready determined it doesn't work then don't bother.

Tom

[Tapper]

Yes, I know all about taking the cup out of a board by running it cup side down. Taking the cup out is easy. It is taking the bow out that is the hard part. If the board is bowed, then hand pressure alone will flatten the board as it crosses the cutter head but will spring back when the cut is completed. 

As someone who agrees with me  in this post, that it takes more force when using an inserted cutter head to take a cut and the deeper the cut the more force it takes. An example would be walking a mile and running a mile. Who will be winded first. I am talking amount of effort applied.

Again, I have used a straight knived, 8 inch jointer for over 35 years. I sharpen my own knives on a surface grinder. I am 76 years old and on a fixed income, and I just don't see a reason to spend the kind of money it would take for me to do it.

I did try out an inserted head jointer a few years ago and the difference in feed pressure really stood out to me. Actually that alone helped me to decided that the inserted cutter head was not for me. Please do not get me wrong there are a lot of pro's to an inserted cutter head.  In a prefect world I would like to have one of each. Again application. This post is about getting a board flat. Again taking the cup out is easy. I do not think one can put enough downward pressure on a 8 inch wide board to flatten the cup out so it can spring back and move the board a crossed the bed of the jointer at the same time. It is getting the board truly flat that is more difficult and the deeper the depth of cut the harder it will be. 

I know from a lot of experience in cutting both wood and metal that more cuts at a lighter depth does a better job than one deep cut. Even my knives stay sharper longer.  Yes it will take a little longer but you are doing it foe fun. Try a lighter cut a few times and see if you do not get better cuts. But if you do please be honest with your evaluation. If you have allready determined it doesn't work then don't bother.

Tom

Tom, quite frankly I'm having a difficult time understanding your point. I'm older than you are and possibly have been pushing boards across a jointer and through a planer longer, but I digress. I've used both straight knife and carbide cutterheads in both my jointer and planer during my woodworking life. There is absolutely no comparison as to which is better IMO. Carbide cutteheads win hands down EVERY TIME. They are quieter, easier to move the material though and give easily as good a result, if not better. And there is no question as to their longevity - it's carbide and not HSS. 

As for cupping and "spring-back" it tends to happen on boards that are cupped and too thin to be able to be jointed flat, due to being too thin. I only use as much downward pressure as is necessary to move the boards through the cutterhead. At 1/32" per pass sometimes it takes multiple passes to flatten one side.

Taking the bow side out of the board is no problem whatsoever, IF the cup side has already been flattened. When you run it though the planer with the now flat side down, the bow is automatically taken out.

If I can't take the bow out of a board with a few 1/32" passes on my jointer, the next solution is to crosscut it so that there is less bow in it. If that doesn't work and if the board is then too short, it's time to move on to another board.

Hope this clears up my position on this subject.

Doug

[tablesawtom]

I am not even going to reply to trapper's second reply. He isn't even considering a different viewpoint only bullying.

Anyway here is a picture of one of my push blocks. Please note the screws in it, they stick out the bottom a very little bit. It was a little trial and error. I press down the push block down on the wood and then I can relax the pressure and move the wood all overt  the jointer table. I can also rock my hand to apply some downward pressure on the outfeed table. The cost is almost nothing and I didn't even have to pay shipping.

[attachment=44025]

[attachment=44026]

My second push block has an end block on it and it is used much like a push stick on a table saw. I do not rely on rubber pads to move the wood like on purchased pads. The rule is an 18 inch in lenght.

[attachment=44027]

 I do have screws in the end and I can jam then into the end of the board. I have one for each end. If the board is bowed I can send it over the cutter head 9 usually about 3 times on the front. I can lift the board upand pull it back over the cutter head without it touching the cutter head. Take a cut, lift it above the cutter head, pull it back and set it down and repeat the process. then move it back of the board and take a few cuts repeating the process. that way I do not have to run the board completely for each pass usually after three passes it is ready to run completely over the knives

[attachment=44028]

I am planning on making a push block that is the length of my infeed table and then making end blocks movable so I can center the end stick blocks. I will make it so the wood push block does not contact the top of the wood so that there is no pressure on the bowed section. Here is a picture of a couple more handled. it is the most time consuming part of the build.

Anyway if you have an ear to hear, then try it you might like the results. If I helped some of the younger woodworkers great. If you mind is closed then don't bother responding. Start your own post.

I will be gone for over a week so I will not be able to respond. 

Tom

[tablesawtom]

In metal working a roughing cut,  semi finishing cut and  finish cut have nothing in common I usually rough out 1/4 on width and lease a couple of inches for finishing to length so sticking the screws into end grain is a moot point. ant the flattening stage. In fact I usually leave material all the way around to be removed after the board has set for a while. So i will send it a crossed the jointer for the final time latter on. I am a hobbyist and my not get back to it for a couple of weeks.

Tom

[Tapper]

Sorry Tom, but I'm not into bullying. Just stating facts succinctly.

Doug