Soft wood to Hard wood problem

[Tim King]

Hi, what screw type would you recommend when joining soft wood to hard wood, like birch plywood to oak. I'm currently having some problems doing this. Some of the screws have been splitting and poking through the oak!! Both pieces are 3/4 inch and the screws I'm using are fine, 1 and 1/4 inch. Thanks

Tim

[Dan F.]

Tim,

You are using the correct screw for your project. One thing you might try is changing your depth collar setting. Try changing your setting from the step of the bit to the depth collar to 3 1/2" instead of the 3 9/16" that it is normally set at. This will keep your bit from driving as deep and will cause less stress on the receiving piece and will stop your screw poking through problem. Sometimes this can be an issue if your two pieces are not exactly 3/4" thick but this should take care of the problem. If you are using two different types of wood in your project it is usually safe to base your screw selection on the piece that you are screwing into and not the piece you drilled your holes into. This is because most of your screw threads will be in this piece. Hopefully this will help you out some with the problems you have been having.

[Tim King]

Dan, thanks for the advice. Well, I went home at lunch and disassembled, drilled new pocket holes at 3 9/16" , and re-joined, but no luck I heard cracking and notice bulges! Would going to 1" screws make a difference?

Thanks
Tim

[Dan F.]

Tim,

If you use the 1" screw it will not leave you with a very strong joint. I think you might have misunderstood my last comment. You will want to change your depth collar setting to 3 1/2". The 3 9/16" that you set it at is the normal setting. If you change it to 3 1/2", the bit will not drill quite as deep thus making the screw not go quite as deep.

[Tim King]

Dan, you're right about the 1" screws. I tried a few and I could pull it appart with my hand. I did have better luck adjusting the depth collar. I went beyond 3 1/2". I forget the exact measurement, I'll get back to you on that. Thanks for your help.

[aric]

I had this problem when I try joining 3/4 inch plywood to 3/4 hard wood. I noticed that on the plywood the screw was not comming out in the center of the plywood it went pass about a 1/16th of an inch.. Most plywoods are not 3/4" as it says when you buy it so i mesured and it was not. So i set the jig to 5/8" and used 1" screws no problem and still a strong joint and the the screw came out in the center