# Dovetails and stock depth, I don't understand?!



## BrianDixon (Oct 10, 2010)

I am making a scroll saw project which is wider than the the 6" wide 1/2" thick boards that I was going to make it from. So I intend to edge join them; this joint will not be visible when the project is done. I decided to dovetail them together, totally unnecessary, I know, I guess I just wanted to play around with making some dovetails, which I have never done.

I have an Incra Twin Linear router table fence,which enables me to cut them very precisely. I took a couple pieces of scrap 3/4" and got the depth of cut right such that they slide together with a little friction. I then took my 1/2" stock and proceeded to cut the dovetails the full length of the two pieces. They won't go together by what looks like a pretty good margin. Because of this fence, I know they were cut exactly the same.

Now, I have read in the Incra manual that cut depth matters with stock thickness, but I thought that pertained to making dovetailed box joints at 90 deg. These are through dovetails. what does stock thickness matter on through dovetails?

I see this as being the same thing as if I were building a bookshelf 4ft wide and wanted to include captured sliding dovetail bookends. In this scenario, I would have mixed stock thicknesses of 4ft and let's say a 1" bookend. If the bookend will start at one end, wouldn't it slide all the way to the other? Would the depth of cut be different than if I simply wanted to edge join two 1" pieces?

I'M LOST! :confused1:


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## Leo G (Oct 16, 2006)

Math doesn't always equate real life. Move the fence until it fits.


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## EWerner (Oct 14, 2010)

With through dovetails both pins and tails need to be exactly the thickness of the joining pieces (which typically are the same thickness). If joining boards of different thicknesses then the pin height needs to be same as the tail board thickness and the tails need to be the same height as the pin board thickness. With half blind dovetails the depth of the pins needs to be the thickness of the tail board.


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