View Full Version : What A Planer Really Does
03-05-2001, 02:52 PM
I just bought the new Delta 12.5" surface planer. While reading some of the posts on this forum I noticed some members suggesting the use of a surface planer to "straighten warped boards".
I was under the impression that if you pass a twisted or warped board through a planer, that's what you get out the other end. The difference is that you've now dressed the face.
Is this true? I thought I would be using my planer to true the thickness of several boards that I may edge-glue together. Not to straighten out warps and twists.
Can anyone enlighten me? Thanks.
03-05-2001, 03:04 PM
Twisted lumber is generally best dealt with by crosscutting off the twisted part.
A planer will take out cup/crown and some bow (short pieces, feed concave side down).
A planer will not help with bent/doglegged lumber.
You can (sort of) deal with twist by making a sled with shims, but it's more trouble than it's worth in 99% of the cases.
03-05-2001, 03:36 PM
This is an area where Mark and I disagree. With your small planner you might be able to rid a board of some cup by taking lots of small passes with the cup down then flipping it over and taking the same amount off the other side. You won't be able to take out most of the other issues without a jointer. I find 95% of my stock is not really flat. It might look straight but when you have run it over the jointer you find that there is always some amount of cup, warp, twist, bow, dog leg to every board. You see wood moves and after it has been cut dried, planned and shipped it keeps moving. It will move after you condition it as well. But, most of the time it is stable until after you have it cut and the joints cut and glued. Then the small movements won't effect your ability to build the piece. You need to understand how wood moves in the design to allow the wood to move and not cause problems in the final piece.
03-05-2001, 08:36 PM
You are correct. I planer will not take the twist or cup out of anything. It's main purpose is to reduce stock to a uniform thickness. Yes, it will do a great job of planing down a surface made up of boards that have been joined together.
I have the same planer and have been very impressed with it. The knives are very easy to change.
03-05-2001, 08:50 PM
I really hate to start another spat, but you CAN remove cup (as defined in the illustration) with a planer. I do it all the time and it works.
The small bench planers will NOT press the board flat. When I feed a crowned board thru on a 1/32" pass it takes off only down the center. When I flip is over and feed the cupped side thru it takes off only on the edges. When I repeat this operation several times on both sides I get a piece of stock that is measurably dead flat on both faces.
This *DOES* work.
03-06-2001, 07:52 AM
Thanks for your help fellas. I can see how 1/32" passes on a cupped board would flatten it out. I'll have to try it sometime. It would seem to me that in these cases you would have to remove quite a bit of material if the cupping is bad.
03-06-2001, 08:09 AM
Yes. You have to remove 2x the depth of the cup. 1/2 from the cup and half from the crown. Ripping the wood and then planing and jointing and regluing will save material.
03-06-2001, 12:33 PM
Re read my post.
I said you could remove cup. But the others are hard to remove with a planner.
03-06-2001, 01:02 PM
What a planer really does is plane wood.
Now that you have one go get some junk crate wood, check it for nails and metal and make chips until you have it down. Follow what the manual sez about planeing, and flatening, and make 1/64" cuts doing it. Not 1/32", not 1/16".
It's a new tool and your going to have to fill a couple of barrels getting use to it.
But when you have it all figured out and see the results, you'll love it.
Remember to feel for the direction of the grain or you'll get chipping in your surface of the board. You may anyway.
Practise and experiance with your new tool. Get a set of extra blades so when you see that funny hairline ridge from a nicked blade, you can change the blades. But unplug it first!
Now go have some fun and work safe.
03-06-2001, 02:18 PM
Was responding more to Boyce. Your observations are correct.
03-07-2001, 08:33 AM
I'm all set Sonny. In fact, my planer came with a second set of blades.