Attaching Legs to a Table

Question

I decided build a table out of 2x4s and such for Thanksgiving. I figured it would be a cool first woodworking project. The top went pretty well I think, but now it's time to attach the legs and I feel like there has to be a better solution than the one I'm thinking about using.

So the 4x4 butts up directly to the 2x10, with the 2x4s at right angles. Everything is reasonably square, but the brackets that I'm planning on using have the tendency to induce a gap between the leg and the table top if there is any issue at all with the screw hole (tested this out on scrap), since the brackets are counter sunk.

One potential solution is using screws with heads that don't take advantage of the counter sink since errors can be corrected by sliding things around a bit, but that doesn't provide nearly the feeling of strength that using the counter sinks does.

Anyhow, I figured someone here might be able to offer some better ideas on how I can properly attach the legs to the top.

Answer 1

Pocket hole joinery

One of the simplest ideas I could think of to address this would be to flip up the boards vertically and use pocket holes and screws into the legs.

Some good examples and picture come from a Community Project post about work benches: Community Project: Lets build a workbench!

Highlighting a picture from my unfinished work bench you can see where I had make the pocket holes. The same orientation of holes is what my table top and frame were made from. That bench is surprisingly very sturdy.

^{Image from my backyard}

All of this requires you have the hardware and/or jigs to make pocket holes. In my opinion they are totally worth it. I have used them on several of my projects and they are very sturdy.

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Add a corner brace

Another idea that builds on my frame suggestion above, still relying on flipping the boards vertical, is to make or buy a corner brace. Note in the below picture that the brace is hiding pocket holes that join the boards to the leg.

^{Image from home-dzine.co.za}

Many commercial corner braces, of various designs, are available as well. Like this metal brace.

^{Image from hertzfurniture.com}

Mortise and Tenon

Another great, and simple, joinery technique to use would be mortise and tenons. However it looks like you have already made your cuts so making tenons would be out of the question. The would have to be long enough to go into the mortises of the 4x4.

Minimum: Flip up the boards

It will help mitigate racking forces against the legs.

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I see in the picture that you have screwed the table top directly to your apron. I would expect as humidity/moisture levels changes that your table top, screws and apron will be moving. Depending on how much stress the expect you could expect some splitting and cracking in the boards. If I am wrong then forgive me but always remember the relationship between wood and water.

Answer 2

All the information Matt provided on joinery is true and quality information. I had a neighbor who built a similar project a few years ago and we ended up with a alternate solution that may be helpful in this situation considering the point you are at. The metal brackets in your picture do not have any cross bracing and that is likely contributing to the instability. Perhaps use a bracket with some cross bracing like these pictures. Personally, for maximum stability, I would go with the wood bracket or something similar. I would apply wood glue and then a few screws. Don't go overboard with the screws on the wood brackets. Their main purpose will be to clamp the brackets while the glue cures. Their secondary purpose is as mechanical reinforcement. If you go with a metal bracket, the screws provide all the bond so be sure the shank of the screw is the same size as the hole so there is no play in it.