Question: MDF and Thickness Planers?

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Blog entry by DeLayne Peck posted 07-24-2012 06:26 PM 3933 reads 0 times favorited 10 comments Add to Favorites Watch

Running MDF through a thickness planner? My woodworking instincts tell me it is a very bad idea. Something about the adhesives and ruining planner blades comes to mind. Yet, I keep encounting times when need odd demensioned MDF for a jig.

What is the wisedom of my brothers?

-- DJ Peck, Lincoln Nebraska. Lord, keep your arm around my shoulder and your hand over my mouth.

10 comments so far

View DS's profile


2141 posts in 1506 days

#1 posted 07-24-2012 06:50 PM

I’ve never had much difficulty running MDF through the planer. Be sure you have good dust collection since the waste is awful to breath.

The only time I ever had a problem was once with some very cheap import garbage, there was a piece of metal in the board and it nicked my blade.

If you did this everyday, I might suggest a carbide tipped spiral cutter. I really don’t feel that one board is going to wreck it, though, I might not run my best blades with it – just in case.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Mainiac Matt 's profile

Mainiac Matt

5361 posts in 1414 days

#2 posted 07-24-2012 07:25 PM

I’ll tell ya what…. you try it first… and tell us how it goes…

my concern would be heat and glue working together to leave a nasty mess on my blades…. so I’m not volunteering to be the guiny pig on this one. :^)

(I know what NAVY really stands for :^)

-- Pine is fine, but Oak's no joke!

View Joe Lyddon's profile

Joe Lyddon

8535 posts in 3138 days

#3 posted 07-24-2012 08:02 PM

NO… I would NOT do it… ever…

... but that’s just me… LOL

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:"

View Howie's profile


2656 posts in 2009 days

#4 posted 07-24-2012 08:20 PM

I’ve always heard not to do this because of the glues.

-- Life is good.

View stefang's profile


14925 posts in 2420 days

#5 posted 07-24-2012 08:49 PM

I guess it’s possible, but compressed paper and glue will very quickly dull your planer blades, so be prepared to resharpen. As an example of what I’m talking about, Michael Fortune the Canadian woodworking whiz says that cutting MDF and plywood in your bandsaw will reduce the blade life by 75%. My own experience pretty much verifies that claim. Composite materials will have the same effect on planer blades.

-- Mike, an American living in Norway.

View John 's profile


212 posts in 2488 days

#6 posted 07-24-2012 09:43 PM

I’ve done it many times with no real ill effects but then again, I sharpen all my blades myself. To tell you the truth, some people won’t run MDF but don’t even think twice about running Pine and Sap Wood through. You will get an occasional sliver of metal in the MDF though no matter where it comes from.


-- John

View gfadvm's profile


13924 posts in 1776 days

#7 posted 07-25-2012 12:58 AM

Looks like the responses are pretty mixed here. I was going to recommend a drum sander if available. I have some 24 grit paper for mine and it will remove a lot of materiel quickly (and that 24 grit doesn’t load up like finer grits).

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View greg48's profile


543 posts in 1843 days

#8 posted 07-25-2012 04:09 AM

DJ, I spent some time around a pulp and mdf mills. All incoming raw material is passed under a large electro magnet to remove foreign particles made of iron, but I’ve seen several instances where long strands of wire get through due to the low mass of the wire and the large mass of chips that cover them. It’s those bits of wire that can cause you grief with saw and planer blades. Good luck to you.

-- Greg, No. Cal. - "Gaudete in Domino Semper"

View pintodeluxe's profile


4185 posts in 1899 days

#9 posted 07-25-2012 04:35 AM

I have done it to make zero clearance inserts for the tablesaw. I do it just before I am going to change planer blades. It won’t harm the planer, but it accelerates wear on the blades.
In fact when Fine Woodworking tests blade life, they plane mdf as a torture test.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View DeLayne Peck's profile

DeLayne Peck

415 posts in 1287 days

#10 posted 07-25-2012 04:44 AM

Thank you so much for your time and all the sage advice. It’s great to be able to bounce a question off so many good heads. Mixed opinions and some real solid cautionary note. Made me think of the old girl in the corner, my ShopSmith. I have added all the stationary tools, but kept her. Think I’ll try mounting a course sanding drum on the SS, horizontally, and patiently work it down by raising the table in small increments. Using dust control and a mask was good advice.

-- DJ Peck, Lincoln Nebraska. Lord, keep your arm around my shoulder and your hand over my mouth.

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