Conformat Screws in Plywood

[Stuart Gardner]

I'm starting work on a new kitchen for my house. I'm making the carcasses from 3/4" Alder Plywood, all dadoed glued and screwed together - front back and sides. I normally use a regular wood screw (pilot holed and countersunk) to screw the plywood parts into the dado. I just recently heard of Conformat Screws and have tried finding opinions about using them for plywood construction, but the internet is woefully lacking on that topic. The screws seem to be designed for MDF and Particle Board use. One craftsman likes them for solid wood shelves dadoed into wood sides. But nobody is touching their use in a plywood carcass. Thoughts anyone?

[Per Swenson]

Stuart,

Nobody is touching their use in plywood, you said it yourself,

they are for MDF and particle board.

Huge thread and no taper or point.

Have a look.

Per

[Jim Becker]

What Per said...Confirmat style fasteners are for materials that chip out easily, such as particle board (including melamine coated sheet goods) and MDF. Plywood is just fine with high quality wood screws, such as those sold by McFeeley's.

[Howard Acheson]

>> The screws seem to be designed for MDF and Particle Board use.

That's what they are for. No need to use them in plywood, particularly for a glued joint. In fact, I never use them in MDF or PB if the joint is going to be glued. Glue is stronger than the support you get from any type of mechanical fastener in composition materials.

[Prashun Patel]

Your glued dado is all you need. Any screws or even brads would only be needed as clamps until the glue sets.

If you need a better mechanical bond than that, you can consider pocket screws, biscuits or dowels.

[Harley Reasons]

I have used the Spax screws available at the HD BORG with great success on plywood and MDF. Woodworking magazine just did a review on screws and the Spax and McFeeleys both rated out as the best when compared against standard wood screws and drywall screws. Again, proves cheapest ain't always the bestest.