MDF for a Zero Clearance Insert?

[jim hollenback]

Yeah I can go buy those spiffy ZCL's for $30 a pop. When you need several it is a bit rich. I'm using plywood now, but they warp. Anyone use MDF for a ZCI? Thinking that the MDF would not warp nearly as much as the plywood.

TIA

[Grant Wilkinson]

I make mine from 1/2" MDF and have never had a warping problem - or any other problem for that matter.

[Mark Burnette]

I made a couple out of MDF and they've held up perfectly for several years. I carpet-tape the original to a rough-sized blank & run it past a trim bit on the router table. Then I drill 4 leveling screw holes, tap them 1/4-20, dribble some super glue in the holes and run the tap through again, then install 1/2" long setscrews. The MDF sucks up the super glue like a sponge and once hardened it makes the threads tougher. Last tip is I glue in a short 1/4" dowel in the back of the insert so it won't lift out without me pushing down on the back to raise the front (this is for a Unisaw).
Sorry for the wordy reply but I don't have a picture of my lowly inserts

[Jon Behnke]

I use corian counter top material, you can get scrap pieces from installers, it machines with regular tools, is very stable, never warps and can be threaded for set screws.

[Bruce Wrenn]

You can get 84 from a 4 X 8 sheet of MDF. For most, that's a lifetime supply.

[Mike Cutler]

Jim

MDF works fine. I have the spiffy phenolics, but if I want to do some odd sized dado's, or angles, with a ZCI, I'll make it out of whatever I have that can be made to fit.
Spend the time to make a really accurate template. it's worth it.

[jim hollenback]

Thanks for the replies. Some good info. I like the super glue in the threads ides.