The v.1 instructions for the various ovens call for nailing together the forms used to build a slab base and the hearth pieces. Newer instructions have shifted to using screws. Should be a one-to-one exchange, right? Three-inch wood screws instead of three-inch nails?
Not so fast. Which screws you purchase is an important decision.
The problem is, they are not meant for being applied using a drill, at least not without pilot holes. They’re serviceable for a few things, but building a concrete form is not one of them. Also, they’re expensive. Johnny Homeowner (that’s me!!) pays through the nose for that pack of 25 wood screws.
For a concrete form, they’re excellent. They have a coarse thread like a drywall screw, only much stronger. (Don’t use drywall screws, by the way; they can shear off before you’re done.) They have a smooth upper shank so that they’ll pull into your second piece of wood without trying to bring the first piece along. The “Type 17” point is a kind of pilot drill that helps you get the screw started easily. They have a Torx star head that won’t strip out, and the box in the photo includes a Torx T-25 bit for your driver.
You’ll find they are a pleasure to use compared to the wire goods version.