need help making "cross halving joint" or "half lap joint"

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Forum topic by grace123 posted 06-17-2011 07:01 PM 9385 views 0 times favorited 9 replies Add to Favorites Watch
View grace123's profile


251 posts in 2965 days

06-17-2011 07:01 PM

Topic tags/keywords: question

I need to repair a picnic table. The legs were made of 2×4. They cross making an X and I believe the joint is called a cross halving joint or a half lap leg joint. Can someone tell me how to make this joint with a router?

9 replies so far

View crank49's profile


4032 posts in 3173 days

#1 posted 06-17-2011 07:20 PM

I lay one 2×4 over the other and position to get the angle I need. Mark both pieces, then separate.

The next step could involve a router I suppose, but I prefer to set my circular saw to cut a 3/4” deep kerf and then make about 8 cuts across the space I want to remove, right up to the lines I just marked and a cut about every 3/8” to 1/2”. Then I just knock the waste out with a hammer and dress it up with a chisel. I could normally be done before I could get a router out of the box and get a bit in it and get the workpiece clamped down.

View lew's profile


12434 posts in 3958 days

#2 posted 06-17-2011 07:38 PM

I think I would make a jig that would “trap” the router base. Something like this-

The distance between the jig sides would have to be determined by the diameter of your router base and the exact width of the leg material. You will have to make the half laps in several passes so as not to remove too much material at a time.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View nailbanger2's profile


1041 posts in 3346 days

#3 posted 06-17-2011 07:43 PM

Crank is right on about the fastest way I can think of, of course the router would be cleaner. If you go the circular saw route, you may want to wedge the saw’s blade guard open, it will tend to fight you. I say this expecting to get killed by the safety police. I have no idea of your equipment or experience with that equipment. Do not do anything that you feel is unsafe.

-- Wish I were Norm's Nephew

View jusfine's profile


2422 posts in 3128 days

#4 posted 06-17-2011 08:04 PM

Nice disclaimer, nailbanger… :)

I can’t talk, in my framing years, I constantly had my guard wedged up on my Sawcat (with a brake) when cutting rafters.

I would recommend Pat Warner’s video where he shows a number of jigs to use with a router, including an especially simple one for the half lap joint which makes them perfectly.

All the Best!

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View Loren's profile


10477 posts in 3850 days

#5 posted 06-17-2011 08:06 PM

I’d do it with a circular saw to define the sides and knock out the
middle with a chisel. Much faster than messing around with a router
to remove the waste. You can use a router to flatten the bottom
and that’s pretty fast and what router planes used to be used for.

You can also saw the sides with a handsaw.

View grace123's profile


251 posts in 2965 days

#6 posted 06-17-2011 08:13 PM

Thanks very much for all the responses. My table saw is currently out of commission which is the reason for the question regarding a router.

View BlankMan's profile


1490 posts in 3555 days

#7 posted 06-18-2011 07:40 PM

This is the perfect example of why I’ve always had a RAS and still do. :-) Even while everybody said the miter saw killed the RAS. LOL

-- -Curt, Milwaukee, WI

View cloakie1's profile


204 posts in 2757 days

#8 posted 06-22-2011 11:33 AM

i would use the compound slider myself…very quick…..but as blankman said a radial arm with a dado head on it….now we are talking fast

-- just get stuck in and have a go!!!

View Mike Harrison's profile

Mike Harrison

4 posts in 4304 days

#9 posted 06-23-2011 12:29 AM

Curt is absolutely, right on the money. The half lap, and a lot of BIG joinery, is drop dead easy on a RAS, and the reason I never got rid of my Delta turret saw.

-- Just my 2 cents worth

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