Advice on joinery for benchtop

18” is wide is enough to assure a weighty bum sits betwixt the edges. For overall strength I’d consider mortise and tenon or beefy dowels which could also reveal if desired.

-- ~Just A Guy With A Hammer~

This picture is looking down from the top, correct?

Going in a completely different direction, you could use pocket hole joinery from below, then hide the holes, or fill them in with plugs. It’s a lot of pocket holes, but you wouldn’t see them, and as long as you get 2-screws at each joint, it should hold up.

You should easily be able to get 2-screws in at each joint if the wood is 2-inches wide and 3/4”-thick. You’d want to set up the jig for the 3/4” setting, then use 1.25” screws (thread count depends on wood being used whether you need the “coarse” or “fine” threads).

I realize pocket hole joinery is sometimes more work, and usually considered less of an artform, that’s for sure, but for this project, it might be worth considering?

If you do go this route, and it’s an outdoor entryway bench, you’ll probably want to use the blue (coated) pocket hole screws. If it’s an indoor bench, you can use the regular pocket hole screws. Plugs would be optional (again, if I’m visualizing this correctly), as you wouldn’t really be able to see them unless you were down on the floor looking under the bench.

I’m sure others will flame me for this, or at least disagree, but using pocket hole joinery here is another viable option (in my opinion), at least, if I’m visualizing your project correctly, assuming the picture above is looking directly down on the bench top.

You will need to drill A LOT of pocket holes for this though, as just looking at the picture above, it would require more than 70-holes and screws to be used.

-- Jonathan, Denver, CO "Constructive criticism is welcome and valued as it gives me new perspectives and helps me to advance as a woodworker."

Hey
I second what Jagwah suggested, But I bet you are just dieing to use that new biscuit joiner, and I think you could.
I would suggest to use Two biscuits at each joint ( thirds ), their centers about 1/4 in. from the top or bottom of the board. Copious amounts of glue, and be sure to put a clamp on each joint to keep them nice and tight until the glue sets up.
The problem with the biscuits is you will probably have to use a #10 or smaller, and even with a #20 you just do not have that much surface area to create a real strong joint. I know people use them all the time for joinery and many will disagree with me, but I think that biscuits are only good for use gluing up wood when you are trying to keep one surface even with the other. To overcome the lack of strength of the joints design the carcase of the bench to support these joints.

-- Chips and Shavings/ see you at WWW.underconstructionlive.com

Thank you for your suggestions. I do agree that I will have to come up with some additional way to strengthen the integrity of the bench, as with either method, I think it will still be weak in the middle. I think I will go with the pocket hole idea for this project, because I think I better just practice with the biscuit cutter before I use it on a project, and I’d like to get this done. I hate to admit it, but the box of my biscuit cutter is gathering dust, and unfortunately, it is the wrong kind——not sawdust!!! I will have to come up with an easy project to use it on the first time. Thanks again for your help!

I would suggest you make a mock up of the design and actually sit on the grid, to confirm how it might feel on your rear end. Based on an 18” wide seat those openings are pretty big and might not be to comfortable.

-- criticism: the art of analyzing and evaluating the quality of an artistic work...

I’d suggest lap joints – and making the members that run left-right in the picture be continuous rather than interrupted.

-- Derek, Bremerton WA --

I’m not sure that I would try this until I had figured out a separate support system for under the “grid”. I certainly wouldn’t trust biscuits, and I doubt if pocket screws would be much stronger.

One idea might be to build a separate framework using 1-1/2” x 2” “stringers” then sitting the “grid” on it so that each piece of the grid was over a piece of the framework. This would leave the grid open, but put the loads on the framework rather than the grid pieces.

-- Adversity doesn't build character...................it reveals it.

Good idea, Sawkerf. jlsmith, I think you are right on the openings. I am going to make them much smaller. I got so engrossed in the construction, comfort got left out of consideration. Derek, the lap joints are a good option.All of you have saved me from making kindling (again) Thanks, everyone!