Half lap Dovetail in aspire

[dboardman366]

I am struggling. I'd like to create a Half lap in the shape of a dovetail for this trestle base. I can't seem to to get the geometry correct. I have been specifically working on the bottom joint. Would anyone be willing to give me some pointers?

[TReischl]

I am struggling. I'd like to create a Half lap in the shape of a dovetail for this trestle base. I can't seem to to get the geometry correct. I have been specifically working on the bottom joint. Would anyone be willing to give me some pointers?

Looks like you have the geometry correct :::shrug::::.

You are saying it is a half lap? Does that also mean you are NOT using a dovetail bit? If you were using a dovetail bit to cut the dovetail shape I believe that is called a "housed dovetail", sort of commonly used between a stretcher and two rails on something like an open base desk.

But I am thinking you are doing just a straight half lap that happens to be shaped like a dovetail.

You are not clear on what your problem is. As I said above, the geometry looks correct. So I am going to assume that you are having fit problems. Right off the bat a given size bit rarely cuts exactly at its stated size, especially router bits. That will cause a fit problem one way or the other. What I do to determine what size a bit cuts is to cut a one inch square by profiling on the outside. Then I measure the square. The difference represents twice the error of the bit when cutting. Then I adjust the size in my database accordingly.

Other than that, not sure where you need help?

[4DThinker]

Pretty close if your want to embed the dovetail end 1/2 way into the base and top. See the attached file.

[TReischl]

If you are truly doing a half lap joint I am not real crazy about it for something like a trestle table that will have a lot forces put on it in the horizontal directions. All that will be holding that leg to the base foot is a very small glue area, and one that is at cross grain to boot. Not good.

If you really want a dovetail I would do the base foot as a three piece lamination, capturing the dovetail much deeper in the center lamination.

If that is being done for looks, well, most people never look under a table to see what joinery was used and they could actually care less.

Just my opinion.