Hardwood Ply and Pocket Screws

[John Yogus]

I am making a bookcase and the frame calls for 3/4" hardwood ply (probably going to use oak). I will be assembling using pocket screws. Would I use coarse or fine thread screws on the plywood? I am relatively new to using pocket screws, so I wasn't sure if the fine thread for hardwoods rule was the way to go for plywood as well.
Thanks for the info.

[Mark Engel]

Use the coarse or Hi-Lo screws for plywood.

[Jerome Hanby]

I used coarse. I also used the ones sized for 1/2" material and cut dados to join the material (also added glue). Probably overkill, but at the time I felt like it helped pull everything into alignment...

[Steve Baumgartner]

The key fact is that the core plies, even in "hardwood" plywood are nearly always poplar, which is pretty soft. Use coarse screws.

[Larry Frank]

The coarse threads are best. Also, be certain not to over tighten or drive the pocket screws. With the plywood and even the coarse screws, you can strip the hole out. I use a driver with a clutch and set it carefully.

[glenn bradley]

One more vote for coarse or hi-lo for ply of any kind.

[Jerome Hanby]

Sage advise!

The coarse threads are best. Also, be certain not to over tighten or drive the pocket screws. With the plywood and even the coarse screws, you can strip the hole out. I use a driver with a clutch and set it carefully.

[Thomas love]

Just curious , why plywood for the frame ,,, do you mean face frame?

[John Yogus]

Just curious , why plywood for the frame ,,, do you mean face frame?

That's what the plan calls for. By frame, I'm talking case sides and top and bottom. It's the design style from Woodsmith #159. I don't have the magazine, but I found the cut list on-line as a down-loadable extra and am working up ideas on construction on my own.

[Jeff Monson]

I'd use the coarse also, careful to not overtighten as stated (easily done).

[Don Morris]

Coarse for plywood or soft woods, fine for hardwoods.

[Rick Fisher]

Funny.. I dislike the fine screws even for hardwoods.. makes me think I don't get it .. Perhaps I should try them again.

[Bill Trouard]

I also recommend the Kreg hi-lo for plywood of any species

[Craig Michael]

Funny.. I dislike the fine screws even for hardwoods.. makes me think I don't get it .. Perhaps I should try them again.

I use coarse for everything. I tried the fine in hardwood and I just don't think they worked great. I have not tried the high low.

[Jim Foster]

O/T, but I'm using the fine in some hardwood White Oak frames I'm doing and they have worked very well.