best way to join boards for a benchtop?

[Wild Turkey]

Got a CL deal on several frames that will make great shop tables.  They are made from 1-1/2" angle and rectangular tubing (both thin wall) so they're not heavy duty but should be great for other duties.  They are 43" square with several cross-braces so I've got several options for installation.  For $10 each I couldn't pass them up.


I'm planning on using some 4/4 Maple I picked up in a bulk deal. It's not furniture grade but is solid.  

My question is what's the best way to join the boards or should I just screw them from below?  

One thought is to joint/edge glue them and just use silicone to hold them to the frame.

Tongue and groove?  Pocket holes?

How much do I need to worry about expansion/contraction?

[K. L. McReynolds]

I once made a landing for a stairway using 5/4 oak(planed yo 1&1/8" thick). I used five pieces that were 50" long and 10' wide. I used biscuits(#20) to join, more for alignment than any holding power. I did need to watch the biscuit placing, since I needed to cut two slices off for steps.

Glued and applied pipe clamps and let set 24 hours. Have not heard of any problems, the job was over 12 years ago.

[fredhargis]

The only movement issue would be if you really tighten the wood to the metal frame without some allowance. So I would joint/edge glue the top together, then put oversize holes (slightly elongated) in the metal frame and screw the top down through those holes. They screws should slide nicely across the metal surface as the wood moves.

[rwe2156]

The only movement issue would be if you really tighten the wood to the metal frame without some allowance. So I would joint/edge glue the top together, then put oversize holes (slightly elongated) in the metal frame and screw the top down through those holes. They screws should slide nicely across the metal surface as the wood moves.

This ^^

[Stwood_]

Joint, rip, shiplap, then attach with screws underneath.

[GeorgeV]

Got a CL deal on several frames that will make great shop tables.  They are made from 1-1/2" angle and rectangular tubing (both thin wall) so they're not heavy duty but should be great for other duties.  They are 43" square with several cross-braces so I've got several options for installation.  For $10 each I couldn't pass them up.


I'm planning on using some 4/4 Maple I picked up in a bulk deal. It's not furniture grade but is solid.  

My question is what's the best way to join the boards or should I just screw them from below?  

One thought is to joint/edge glue them and just use silicone to hold them to the frame.

Tongue and groove?  Pocket holes?

How much do I need to worry about expansion/contraction?

USE DOWELS