Screwing into plywood

[andrew whicker]

Hi,

Potentially dumb question:

Can you just screw into plywood endgrain? No pocket screws. Just literally pilot hole perpendicular into the 'end grain' and then screw into it?

My friend is making drawers for his pickup truck and long story short, he has a metal frame and wants to put plywood into the metal frame. So he was thinking of building a metal frame like a picture frame and then putting the plywood in the middle. He wants to screw the plywood into place from the outside of the metal box inward. The screws would go straight into the frame.

Attached picture because I'm terrible with words

0201181124a.jpg

[Adam Herman]

best to build the frame with angle and set the ply into it. screws into the edge of ply often split the ply and do not have great holding power. other option is to weld some tabs on the bottom to hold the ply. best way to build anything is to not rely on the fasteners for structure, but to use mechanical means, such and dadoes, tenons, etc.

[Dave Haughs]

Yes you can

[Jerry Miner]

Short answer: Yes, you can.

Screws driven into plywood hold better when driven into the face, but they do hold when driven into the edge. Lots of utility (and other) cabinets are built with screws used this way.

[Jason Baker IX]

Should you do this? Probably not. It doesn't sound very sturdy for something that might be bouncing around in a pickup truck. Personally I would add some solid wood braces screwed into the metal frame, and then screw the shelves onto the top of the braces.

[Ted Derryberry]

A lot of it depends on the quality of the plywood. If I understand the drawing correctly and you're depending on the screws to hold up a plywood shelf I wouldn't do it that way. They'll split out eventually under load and the stress of bouncing as mentioned above.

[andrew whicker]

This is a vertical piece that will hold the drawer slides.

[Ted Derryberry]

You might get away with it as long as he keeps 4 wheels on the ground in the corners.

[Lee Schierer]

Yes you can

I would recommend drilling properly sized pilot holes in the plywood edge and use longer screws than normal to get extra holding power.

[Jim Becker]

I would recommend drilling properly sized pilot holes in the plywood edge and use longer screws than normal to get extra holding power.

I agree with this and will add that it may be a good idea to use screws that have a coarser thread, too. My tack trunks use butt joints for the basic carcass construction along with glue and screws. While I have to use smaller #7 screws for this, I make them much longer than I would for many other constructions. While most of the strength clearly rests in the glue, these longer screws do provide a little additional support.

[John K Jordan]

I would recommend drilling properly sized pilot holes in the plywood edge and use longer screws than normal to get extra holding power.

Where concerned with screws splitting the wood I've even done this which might sound odd: drill improperly sized pilot holes, holes almost too large where the threads were biting but not enough to exert a lot of side force. Then dope the hole and screws with epoxy and assemble. This prevents re-tightening the screws later but holds well. I also have used this to secure small things from hardwood where I needed a single screw in end grain. So far this has always worked.

[lowell holmes]

I would not do it for use in a pickup. It will weather with time and possibly split.

[glenn bradley]

I would recommend drilling properly sized pilot holes in the plywood edge and use longer screws than normal to get extra holding power.

I agree with this and will add that it may be a good idea to use screws that have a coarser thread, too. My tack trunks use butt joints for the basic carcass construction along with glue and screws. While I have to use smaller #7 screws for this, I make them much longer than I would for many other constructions. While most of the strength clearly rests in the glue, these longer screws do provide a little additional support.

I'm in this camp. I treat plywood edges the same as MDF when screwing; proper diameter hole for the fastener, a bit deeper hole than required and clamp the location to prevent splitting/delamination when driving the screw.

[Brian Holcombe]

When this is done, the plywood is usually captured in something (like a dado) to help prevent it from splitting between the plies. Since this is not possible here it would be better to have a length of metal running along the side of the plywood.