Clean Cuts in MDF

Saw marks on cut edges could be a problem of fence alignment. Here's some advice on getting straight, clean cuts. October 9, 2006

Question
I know a lot of shops use a lot of different blades for different material. Well, I only use MDF (door shop) and I'm having problems finding a good sawblade. I'm looking for one that can cut a finished edge on MDF to eliminate sanding or most sanding. I've tried a lot of blades and always get tooth marks I have to sand out (takes too much time). I use a super-refined MDF that's pretty soft. Can anyone suggest a type that will give me better results?

Forum Responses
(Cabinetmaking Forum)
From contributor B:
Could be it's not the blade. Check the run-out on the blade and, of course, parallel alignment of fence to blade, assuming you have a cabinet saw. A couple of years ago, I purchased a new PW 66 and the arbor was out .003" from the factory!



From contributor G:
What type of saw do you require? Is it a panel saw or table saw? If you are getting teeth marks, a few things to look atů First, as mentioned, it could be the arbor, or the stabilizers (make sure there is no debris). A triple chip will do the job with a 6^ hook angle.


From the original questioner:
Thanks. I was wondering about the alignment. I was thinking about just getting a new fence system anyway, as I don't like the one I have. I have a JET table saw and I don't have much confidence in their fencing. I thought that might be the problem and was thinking about junking it and putting a shop fox fence on it. I know someone with one and they seem to be able to take more abuse (bumping with sheets, MDF is heavy). As for the blade, I'm going to try that too.


From contributor D:
A note on the shop fox fence... I have one. It does take a lot of abuse and I really like it. The only thing I found was the HDPE sides weren't as flat/straight as I wanted them, so I had to shim them. I think it'll be easier just to replace them with MDF sides instead.


From contributor A:
Why, oh why, are you pushing sheets of MDF around on a table saw? If you're a small shop, and I suspect you are if you're using a TS, consider either a relatively inexpensive panel saw, or, for really low cost, build a flat torsion box table top (it will stay flat for a long time) about 3' x 7' (assuming you're working with 4' x 8' panels), drop a sheet of foam insulation on top, and buy a Festool circular saw. (This saw is made for cutting panel material - costs about as much as an inexpensive contractor TS.) With its included guide, this saw slices up panels as pretty as you could want. It's much easier to push a 10 lb. saw around than 25 - 100# pieces of panel.


From the original questioner:
Thanks for the info. That must be a problem with all of them. The guy I know with one sanded or planed down the HDPE and refaced it with a piece of Formica. I never asked why he did that; must have had the same problem.