# Half lap advice, please?



## jbswearingen (Jun 27, 2012)

The missus has tasked me to design and build a pair of writing desks for our daughters, modeled after one she found online.










I plan on using half laps to join the two triangle frames. The bottom rear one is no challenge; it's 90*. The lower front and top are a bit more of a challenge.

I do have an old-style Delta tenoning jig that I intend on using:










I've designed the desk in Sketchup and will print out pieces so I can measure the angles. My question is this: How do I transfer the angles and ensure that I cut them correctly with the jig on the table saw? Is it something really simple that I'm just missing?

Any help would be greatly appreciated.


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## CraftyCantrell (Jul 6, 2016)

Here's a pretty good video of doing mitered half laps on a table saw.


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## Unknowncraftsman (Jun 23, 2013)

Now that's a cool looking tenon jig I can see why you want to use it.
To find the angle make a full scale drawing and grab the angle from the drawing.
Test your cut on scraps till your happy.


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## rwe2156 (May 7, 2014)

If you're dead set on using that tenon jig, I refuse to help you. :-D

If you want a better way, scribe line, cut with a handsaw and use a router plane or rabbet block plane.

You'll be done with it by the time you figure out now to cut an angle with a tenon jig.

[Brad, feel free to cut and paste the following and put note in wife's dresser drawer]

Note to Mrs. Brad from a fellow LumberJock:

Your husband needs proper tool for him to build a project of the quality the love of his life deserves.

So if he doesn't have a router plane, you need to buy him one TODAY.

And if he doesn't have a rabbet block plane, please buy him one for Christmas…....or Labor Day.

Feel free to contact me I can tell you right where to buy them.

(LN…..out)


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## jbswearingen (Jun 27, 2012)

Ha!

I only own a few planes, and those are much bigger than block planes.

Will a router plane work across grain when cutting tenons? Do they have a scoring blade to cut the grain?

I'll probably go with the table saw method mentioned above, as once it's set up, it's repeatable-I actually plan on building four of these, total. Two for my girls, one for a niece, and a fourth to try and sell.


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## TheFridge (May 1, 2014)

You chisel the baseline as you go.

I'd scribe it. Cut the majority out with a TS sled and fine tune with chisels and router plane.


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## Tootles (Jul 21, 2011)

You cut the pieces of the frame to the correct length and angle, then place them in your tenoning jig such that the end grain is flat to the table. Is it more complicated than that?


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## jbswearingen (Jun 27, 2012)

> You cut the pieces of the frame to the correct length and angle, then place them in your tenoning jig such that the end grain is flat to the table. Is it more complicated than that?
> 
> - Tootles


I don't know. I've never done it before, which is why I ask for advice.

Is that not simple enough?


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## Tootles (Jul 21, 2011)

Brad, I have never done it before either. But I think of it this way.

For a 90° tenon / lap, you cut your wood square and to length on the table saw and then clamp it into the tenoning jig standing straight up into the air with the end grain flat against the table. Then you push the wood through the saw and the blade cuts parallel to the end at whatever height the blade is set.

If you did the same for and angled tenon / lap, then the only differences should be that (a) the wood is cut at an angle (by setting the miter gauge on the table saw to the angle that you worked out in Sketchup), not square and (b) the wood is not standing straight up into the air, it is standing at an angle. I will admit, however, that really low angles could be a problem to fit into the jig and still clamp properly. That might prevent you from using the jig for the joint at the apex of the top triangular frame.

Does that help, or am I on completely the wrong track (not uncommon I'm afraid)?


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## Kirk650 (May 8, 2016)

Good grief. You guys are making a simple job into something difficult. I use the table saw and the miter gauge, and don't even put the dado stack on. I just use the standard blade. Easy and fast. I clean up the cuts with a block plane. A router plane is, to me, too slow.


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## jbswearingen (Jun 27, 2012)

My apologies, Tootles. I misread that and responded a bit too snippish.

Thanks for the ideas, folks. I now have a plan to attack this. I appreciate the brainstorming.


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