What's the fastest way to cut a whole bunch of half lap joints?

[ChetlovesMer]

Okay, so this isn't exactly fine woodworking. But my bride would like a me to build some sturdy shelving units in our basement utility room this weekend. Basically a bunch of 2x4's with half-lap joints and 3/4" Partical Board shelf-tops.

For the number of shelving units I am building I figure that means I'm going to cut 160 half-lap joints!!!!!

It doesn't take a genius to cut a half-lap joint in a pair of 2x4's. But my question is anyone have any thoughts about how I can do this quickly.

Most of the shelving units are exactly the same so I would think there should be oportunities to cut a whole slew of 2x4's at one time. I just can't quite figure out the quickest (safest) to do it. The lap joint will be 3/4" deep and 3-1/2" wide and I will be putting them in the same places in most of the boards. I'm up for building a lap joint router jig, but I was hoping to be able to do mulitiple boards in one pass. I was thinking about using the dado blade in my table saw, but I couldn't figure out how to fixture a bunch of 2x4's.

Anyone have any ideas?

Oh, I should mention that I have a well stocked shop full of tools. About the only tool I don't have is a radial arm saw.

[DaBear]

if it were me, I'd use a bandsaw (with a stop) for the 'rip' cut, and then trim the waste out with a crosscut on the tablesaw. Still a lot of work, but relatively straightforward to 'jig up'..

[dwacker]

Radial arm with a dado blade. Crosscut sled on the table saw, you can easily do two at a time just hand holding. Set up a stop block for each cut and start cutting, it wont take as long as your think.

Don

[ChetlovesMer]

Crosscut sled is a good idea.

I think I'd build a new sled for the job. Today I have a thin kerf sled and a normal kerf sled. I don't have a dado sled, but that's probably the best idea I've heard so far. Thanks.

[dwacker]

Crosscut sled is a good idea.

I think I'd build a new sled for the job. Today I have a thin kerf sled and a normal kerf sled. I don't have a dado sled, but that's probably the best idea I've heard so far. Thanks.

If you dont have a sled already but have a spare miter gauge the you can just bridge them. I dont use crosscut sleds even with 30" wide ply just a bridged pair of miter gauges. I use a long piece of 3" wide ply for the face and another piece screwed to the back to stop any flexing. Use it abuse it the throw it out.

Don

[Jfitz]

Don - great idea! My CC sled is not large enough for some ply panels I'm going to be making, and I was toying with either making a larger sled, removing the front fence from my current sled, or using a straightedge and circ saw (but I was worried about getting consistent 90degree cuts).

[Mike M]

I'd vote for the bandsaw method suggested by the Bear from the North. Even if you do a final cleanup with a router or dado stack, the reduction in sawdust is worth the extra step.

[Mike L B]

You might want to reconsider the use of particle board for the shelves. It will sag under minimal weight, plywood would be much stronger.

[rodger.]

+1 on the plywood. Plywood is far stronger, and not really much more expensive.

Another method for half laps is a chop saw (with a depth stop) and a chisel. Cut a number of kerfs about 1/8" apart on your chop saw, then just clean it up with a chisel. The remaing thin strips of lumber in the joint will peel right off. I have used this method before a few times - its great for rough carpentry projects like decks and basement shelving.

[Bombarde16]

My vote's for a router jig, or a similar jig to make them with a circular saw. (Same concept, just that a circular saw will waste out material faster.) Dimensional lumber is notorious for twisting and warping and, for such a project, I wouldn't want to be bothered getting things flat and true. So using a sled or a table with a large surface area (such as a table or radial arm) might lead to a warped piece not laying flat and not getting cut accurately. Something with a smaller footprint will allow you to focus on cutting to proper depth in one part of a board, regardless of what the rest of the board wants to do. Once the joinery is cut accurately, then you can clamp things into submission at assembly.

Maybe I'm not seeing things properly, but a band saw would only be able to make half laps at the end of a board, correct? Perhaps the OP also needs lap joints in the middle of a board.

[JMadson Custom Wood]

What about laying the boards side by side and cutting thru a whole bunch at one time? You could use a router with a wide bit to take a big enough pass that you would only have to adjust a fence 2-4 times.

[harryangel69]

I would do a crosscut sled. That many cuts just a special one time use sled like 6 or 8 feet long for work support. Clamp in several at a time. Doesn't have to be dead perfect just efficient.

Actually I would dig out my dads old radial arm but that's no help.

[Ronn W]

I vote for a cross cut sled with a stop at 3 1/2" and a dado stack provide the pieces are not to long.  Only takes a few seconds to make 4 or five swipes across the dado stack.   If the pieces are too unwieldy you might be able to do 2 or 3 at a time.

[..Kev]

Table saw  and a dado stack.  No need for the sled.  Once you get it set up, you can crank them all out quickly.

[AstroDave]

I vote using a CNC.... I kid I kid

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[gee-dub]

I use a tenon jig on the table saw. One setup cuts all the cheeks, one setup it's all the shoulders. Minimal spoil.

[bleedinblue]

Domino.

[wtnhighlander]

Froe and mallet?

[shaneymack]

No one realised this thread is from 4 years ago?? Pretty sure op half laps are all done....

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[..Kev]

1 minute ago, shaneymack said:

No one realised this thread is from 4 years ago?? Pretty sure op half laps are all done....

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He could still be pondering

 

[bleedinblue]

Crap.  That sort of thing usually sticks out to me like a sore thumb and drives me nuts.  I done got got.

[Guest]

Chet (the OP) is another one of those guys that was pretty active here then just disappeared one day without a trace.  Funny how that happens.  

[gee-dub]

Often new responses to old topics are still relevant.  Would we respond differently if someone else asked the same question anew?

[Guest]

6 minutes ago, gee-dub said:

Often new responses to old topics are still relevant.  Would we respond differently if someone else asked the same question anew?

depends on who is asking it.  some folks get a little hazing first.  

For example, one answer to Chet's question might be:

First off, don't even bother with half laps in 2x4's and particle board.  Get yourself a kreg jig, or better yet some twine, and call it a day.  But seriously, this is an expensive hobby.  If you are going to build something, do it right.  Your wife wants real wood, not that soft stuff from the home depot guy.

 

 

 

[Cliff]

On 5/4/2016 at 11:54 PM, TIODS said:

Table saw  and a dado stack.  No need for the sled.  Once you get it set up, you can crank them all out quickly.

I just did this on about 20 or so last night. Took me about an hour to dial it in because I had to find half of 1 3/8" Then i just mowed through them. Much much better quality cut & squareness than I had from my router jig that I built for doing the same thing.