Why is there a minimum thickness on a planer?

[John Huber]

My Delta Jointer/Planer says not to plane stock thinner than 1/2". I want to plane stock as thin as 1/4". Is this thickness limit severe? What should I do to remedy it? Thanks for any help.

[Jim Becker]

Most planers will go to 1/4" and some (the lunchbox type) will go to 1/8". The limitations are based on the mechanism of the particular machine, roller type/design as well as the need to insure that the knives cannot come in contact with any of the above.

[Scott Loven]

Use double sided tape to stick the wood to another board, then plane as thin as you want.
Scott

[Dave Falkenstein]

Adding a base to the planer bed will usually allow planing thinner material. I use a base of 3/4" melamine, cut to the width of the planer, several inches longer than the extended infeed/outfeed tables, with a cleat at the infeed end to anchor the base on the bed of the planer. I can plane to 1/8" on a Jet 12-1/2" planer with no problem.

[Lee Schierer]

As the others have said, most planers have a minimum height setting that prevents damage to the knives or works around physical part limits in a particular design. You can also plane thinner using sleds or double sided tape to hold you stock to a carrier board.

Just proceed with caution. Some figured areas of the wood will shatter when cut too thin, and although I've never had an damage done to the planer, it sure sounds bad and ruins a good piece of wood. Areas of grain where the grain is basically diagonal to the top and bottom surface is particularly prone to do this.

[John Huber]

Thanks to all for your helpful replies. I'll carpet tape a 1/2" thick backer to the workpiece that is the same width and length. That will make it stiff enough and also push the guard out of the way.

[Bruce Page]

Thanks to all for your helpful replies. I'll carpet tape a 1/2" thick backer to the workpiece that is the same width and length. That will make it stiff enough and also push the guard out of the way.

John, add a couple of small wooden stops to the outfeed end of your carrier board. Carpet tape alone might not be enough.

[Bruce Benjamin]

This question was asked on another forum at the same time by the OP and the same thing happened. I think he's talking about a jointer, not a thickness planer.

Bruce

[Frank Fusco]

Most planers will go to 1/4" and some (the lunchbox type) will go to 1/8". The limitations are based on the mechanism of the particular machine, roller type/design as well as the need to insure that the knives cannot come in contact with any of the above.

What is a "lunch box" type planer?

[tod evans]

What is a "lunch box" type planer?

any planer one man can pick up and carry.....02 tod

[Jim Becker]

What is a "lunch box" type planer?

Examples would be the Delta 22-580 and the Dewalt 735...portable planers, typically in the 12-13" width range. You can pick 'em up with two hands, although the Dewalt really requires a strong back. (And the "best" hearing protection...)

[Dev Emch]

any planer one man can pick up and carry.....02 tod

Would that include any planer that is totable by Paul Bunyon and his blue ox babe?

[Alex Berkovsky]

...I think he's talking about a jointer, not a thickness planer. I think you're right... he did mention pushing the guard out of the way.

[Cliff Rohrabacher]

I think he's talking about a jointer, not a thickness planer. Bruce

Then why has he got the question at all?
Unless the jointer is set to take too big a bite you can joint any thickness ya please.

[Julio Navarro]

Confusing a planer and jointer seems to be a common thing. The funtion for both machines is similar, the jointer looks more like a hand plane than the planer, hence the confussion.

[Bruce Benjamin]

I think you're right... he did mention pushing the guard out of the way.

I know I'm right. As I said, the op asked the exact same question on another forum and it was ironed out there pretty quickly. That and the op called the tool a, "Jointer/planer" already.

Bruce

[Bruce Benjamin]

Then why has he got the question at all?
Unless the jointer is set to take too big a bite you can joint any thickness ya please.

Are you kidding, Cliff? I'm not sure if you're still doubting that he's asking about a jointer or not or if you seriously don't think there's a safe limit to the thickness of a workpiece to be jointed. My planer will plane down to 1/8" thickness according to Dewalt. But I think it would be pretty stupid for me to take that same 1/8" piece and try to face joint it on my jointer. First of all, it's not safe. Second, it's likely that the piece will flex if you're pushing down on it as you pass it over the jointer knives so it won't accurately flatten the workpiece. If his manual says not to do it, maybe he shouldn't do it.

Bruce

[Frank Chaffee]

What do ya’ll think of using a backer board to joint thin stock?

Frank

[tod evans]

What do ya’ll think of using a backer board to joint thin stock?

Frank

why? if it`s thin enough to need a backer it`s flexable enough to force into submission for whatever the application is..02 tod

[Charlie Plesums]

If the question is for a jointer, the I wouldn't consider running anything close to that thin... how would you keep it from flexing, and thus defeating the purpose of jointing.

If the question is for a planer, there is the concern about keeping the cutters away from the rest of the mechanism, but there is also the issue of the lift. Cutters tend to lift the board, expecially with deeper cuts. So using a backer board will keep the cutters out of harms way, but it won't keep the cutters from tending to lift the work piece. And the thinner the work piece and the more figured (fragile), the more likely it is to be drawn into the cutters. Can it be held down with carpet tape? Perhaps with lots of tape, but it depends on the depth of cut, the thickness of the work, and how fragile the piece is. Said another way, if the wood is really valuable, the planer will eat it.