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(Apologies if this has been answered before. This probably has a really obvious answer.)

I need to connect two 4x4s in a "T". (These are one leg and a center / longitudinal support for a long table.)

I decided on a half lap joint since it looked relatively easy to do, but my wife doesn't want to see the back of the joint on the table feet. I thought: easy enough, I'll just make it a blind joint so that the end of the long board doesn't go all the way through, leaving about 3/4" on the end of the lap.

However, I'm not sure what the best way is to cut this into the table foot (about 32" piece of 4x4). My initial attempt on a piece of scrap was to drill a few holes in the corners of the waste area, hit it with the jig saw and chisel out the rest. This works, mostly, but is something of a pain and doesn't get me a smooth surface at the bottom of the cut for the long board to mate with.

I'm not super-comfortable with the idea of putting a 1.5" bit on my router as I'm a bit afraid of snapping the shaft if the teeth catch on a knot.

Suggestions? I considered a mortise-and-tenon joint, but that leaves me with the problem of cutting a 1.5-1.75"-deep mortise, which is basically the same issue I'm having here.

I could probably just get a large bit or hole saw, use my neglected drill press and clean up the excess with the jig saw or chisel, but is there a better / more accepted / safer way to do this?

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Kudos for doing a test run first and identifying the problem ahead of time!

Standard advice from older woodworking guides (or any modern handtool book) for doing many things like this: cut the bulk of the material out with the chisel (if you like drilling out some waste first), then smooth the bottom of the recess/channel/dado with a router. In the old days this would have been a hand router but you can do the same thing with a powered router of course.

Suggestions? I considered a mortise-and-tenon joint, but that leaves me with the problem of cutting a 1.5-1.75"-deep mortise, which is basically the same issue I'm having here.

Not really, since the bottom of a mortise doesn't need to be clean at all. In fact the bottoms of most mortises probably look like they were chewed by a beaver. Long as the side walls of the mortise are clean though that's all that matters.

The M&T is the stronger joint, but the half lap (UK: housing joint) is plenty strong enough for what you're doing here if it's cut well and the parts are glued together properly*.

I'm not super-comfortable with the idea of putting a 1.5" bit on my router as I'm a bit afraid of snapping the shaft if the teeth catch on a knot.

You can use a long bit with safety to cut deeply even into very hard wood if you just take a little off at a time. If you had to you could just nibble away 1/8" or less at a time.

A slower feed rate helps reduce the strain on the bit as well, although this can increase the chances of scorching.

Just thought I'd tack this on for anyone with a table saw who might like to try an alternative......

'Cheating' using a table saw
If you have a table saw and the raw material for the legs is thick enough that you can afford to lose some there is a workaround method.

First you saw a thin strip from the leg (you'll lose about 1/8" or so to the kerf), then you cut the lap through on the thicker portion, which is straightforward to do and it's easy to get a nice flat surface using a sharp chisel with fine paring cuts to finish off. Then you simply glue the strip back on the leg, closing the back of the joint.

This can create a seamless joint on the leg if the grain is nice and straight or if the wood is a tight-grained species without obvious grain lines or figure that would be interrupted by the cut.


*Use enough glue that some squeezes out, use plenty of clamp pressure.

  • Wow - thanks very much for taking the time to write such a detailed, articulate answer. I'd considered the table saw cheat, but it felt like a hack. Then again, I am a programmer, so I shouldn't be surprised. :) – 3Dave Jan 6 '17 at 23:13
  • @DavidLively Either most of woodworking is a hack or none is depending upon your viewpoint. In my view, if it works and looks good its not a hack, its fine woodworking! – Ashlar Jan 6 '17 at 23:22
  • @Ashlar Hacks aren't bad (especially when it's not something that's going to have to be dismantled/maintained later on)! I had chisel issues awhile back while trying to slot shelves into routed 90-degree notches in table legs. I tried removing the little-round-ish-bits inside the slots with a chisel, split a $30 leg that I'd spent hours making. After that, I just notched the corners on the shelf instead and everything was fine. I'll probably burn in amateur-woodworker hell, but it was fast, easy, and it worked so... I'll take it. – 3Dave Jan 6 '17 at 23:25
  • @Ashlar "most of woodworking is a hack" yes! You should get t-shirts printed up with this slogan on 'em :-) – Graphus supports Monica Jan 6 '17 at 23:56
  • @DavidLively Welcome David! Re. your shelves issue with the table legs, presumably the split followed the grain, in which case it could have been glued back together no problem. Where wood splits along the grain, especially if the split is very very fresh, generally glue together extremely well. At best the fix is invisible, and the piece ends up just as strong as before it was damaged. That said, notching the corners on the shelf instead is a perfectly decent solution as well, numerous published projects have a shelf done that way too. – Graphus supports Monica Jan 7 '17 at 0:01

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