Need screw advice for butt joining 3/4" Baltic Brich plywood

[Al Bacon]

I need to butt join 3/4" plywood. I can't use a dado in this project. I have a choice of 7mm X 50mm comfirmat screws or Spax #10 or #14 X 2". Which would give the most strength? Glue will be used in the joint as well.

Thanks

Al

[Ethan Melad]

I think it somewhat depends on the application, but assuming its a cabinet I see no problem with a #10 spax. Confirmats are great too, if you've got the right drill bit.

[Al Bacon]

I do have the confirmat drill bit from another project and plenty of screws. That project called for joining MDF and the confirmats were recommended for that application. The resulting joint was very strong and that's why I was asking about using them on the plywood. If the Spax would make a stronger joint I would go that route. And I do have a supply of the Spax as well.

Al

[George Bokros]

If this butt joint with one piece at 90* to each other why not pocket hole joinery if it will not be seen?

[Frederick Skelly]

FWIW? Last year I built a really nice cabinet style stand for my Delta contractor saw. I used 90* butt joints, regular old deck screws and glued-in corner blocks ( in several high stress areas). In a year its been rock solid. I used carefully pre-drilled holes that were spaced 4 -6" apart. 2" deck screws.

[Jim Dwight]

My first bedroom set was softwood shelving boards and 2X lumber joined with #8 wood screws with the holes plugged. I built that in Philadelphia (in an apartment), moved it to Kansas City, then Omaha, then Pittsburgh, then Columbia, SC. It still worked fine when we gave it away in the last move. These days I use drywall screws. The glue really holds things together. I don't think the type of screws matters as long as it pulls things together and holds until the glue sets up. I might use the pocket screws because I think they would be less likely to split the plywood. They also hold surprisingly well. I used mainly pocket screws on my shop vacuum cart (made of 3/4 BC plywood).

[Jeff Duncan]

Spax won't be stronger, but they are easier. Confirmats are a "stronger" joint in that they're both screws and dowels in one fastener. Hard to beat that. But they are more time consuming to drill and install so….?

good luck,
JeffD

[Greg R Bradley]

The only thing I have to add is that #14 Spax Screws into the end of 3/4 Baltic Birch", usually actually 12mm, may have bulges where you try to screw in #14 screws pilot drilled to the correct size. Please don't ask me how I know and let my mistake help you from making the same mistake.