Screw Sizes for Cabinet Box Construction

Cabinetmakers discuss screw preferences for assembling carcases. December 27, 2008

Iím considering switching from Confirmat screws to Zip-R screws for butt jointed melamine boxes. Also want to use the same screws for butt jointed and plywood boxes with dados. What length Zip-R screws are you using? All 3/4 stock.

Forum Responses
(Cabinetmaking Forum)
From contributor C:
#6 x 2 for butts, same for b'dado'd joints. No glue.

1/4 crown x 1-1/4 staples for the quick pin-ups of butt joints, just enough to align and hold, then the screws.

From contributor A:
Contributor C, I hope you hit the wrong key. Please check your boxes. They must be #8 x 2". #6's are very small screws. 18 gauge 1 1/2" staples are also available. When we do butt joints we use 1 1/2" staples with #8 x 2". We mostly use rabbets/dadoes with pre-finished plywood. At this point we use 1 1/2" staples and glue. No screws. We always use 1 1/4 - 1 1/2" staples for the 1/2" backs.

From contributor C:
We do in fact use sixes. Six. Number six. #6. Try some out yourself. Put a simple cube together, one side with sixes, the other with eights. Now use whatever destructive forces and tools you need to knock the box apart.

As for staple length, we are just asking those 1-1/4-length things to hold the joint in registration just long enough to get the screws in. They are just fine, and the shorter length makes for less blast-throughs due to someone getting sloppy with the angle.

From contributor A:
I'll give it a shot if I can find some #6's kicking around in the shop. Not trying to be critical of your methods and/or madness. I have become more of a minimalist as the years have passed. We do use more of the stainless trim heads now for interior box screws. I believe those are #7.

From contributor K:
Actually you may be weakening the joint with bigger screws. The bigger the screw, the more chance of it splitting the material it is driven into. I like smaller ones.

From contributor R:
I was just looking at the Quick Screws website. All the flat head type 17 assembly screws with nibs are #8 or larger. Where are you getting the #6?

From contributor C:
Hafele is my source and Zip-R is the spec.

From contributor J:
I just used the SPAX #6 x 2" screws on melamine boxes for the first time and I'm a believer! Never thought I could get away with screwing into melamine without pre-drilling, but they work like a charm.

From contributor W:
Spax is a good screw. Have not used them in while!

From contributor R:
I assume you're using the partial thread Spax screw. Is that correct?

From contributor J:
I didn't even know they had different configurations of the SPAX? I just checked and the ones I'm using have thread running the full length. I haven't tried the Zip-R screws yet, not sure if they're better or the same...

From contributor A:
The Zip-R's are the typical typ 17 countersinking nib construction screw that Quickscrews distributes as well as McFeely's, a lot of plywood distributors, etc. Hafele calls theirs Zip-R's.

From contributor S:
I use* 2" #6 Zip-R screws. With a thinner diameter it helps to have a longer screw to help resist pullout.

* I don't use many face screws to construct boxes anymore, since I've gone over to the dowel side.