# Single Pass Half Blind Dovetail Issues on an Upgraded Leigh D4 jig



## EarlS (Dec 21, 2011)

I spent yesterday trying to find a work around to make single pass half blind dovetails on an upgraded Leigh D4 Dovetail jig. I'm making 32 drawer boxes to be used in custom closet cabinets in our new house. Using single pass half blind dovetails would take considerably less time than regular half blind or through dovetails.

The jig was updated to a D4R Pro. However, the spacer that is called for in the D4R Pro instructions leaves the tail board offset too far. Rather than the edge of the tail board being in the middle of the opening between the first and second guide fingers, the edge lines up with the 2nd and 3rd guide fingers, creating tails that are off by 1/2 of a socket.

The issue seems to be with the D4 side stop. The D4R-Pro side stop appears to be integrated into the jig base rather than a separate piece like the D4. As a result, the spacer does not slide over the side stop on the D4 like it shows on the D4R instructions (11-7).

Has anyone had a similar problem or know of a solution? One option would be to make a spacer that is only as wide as the thicker section of the D4R spacer that should properly offset the tail board, or revert back to making regular half blind dovetails in a 2-step process as detailed out in the D4 instructions.

I plan to call Leigh and ask them as well.


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## splintergroup (Jan 20, 2015)

I have the DR4pro and have not noticed any issues (though I've only tried it as a quick test)


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## RichT (Oct 14, 2016)

> However, the spacer that is called for in the D4R Pro instructions leaves the tail board offset too far


That spacer won't work. You need to make your own per the upgrade instruction sheet I link to below.

I did the upgrade for my old D4 a few months ago and have it set up perfectly.

Some of the issues I ran into getting it set were finger spacing, the left-hand offset that you mentioned and the depth. Fortunately, since I use 1/2" drawer sides most of the time, that doesn't have to be adjusted, although it would be no big deal if it did since I tool a photo of how this is set and it would be easy to return it to that spot.

They tell you in the upgrade instruction sheet that the left-side spacer that's included won't work with the D4 upgrade. You'll need to cut your own. What I did was run a small board through my planer until the thickness was exactly 0.544" (what the upgrade notes call for) and then sliced off a couple of spacers. I have one stuck to the jig with double-stick tape and another spare one in my parts box.

The other thing I found was a bit touchy was the spacing for the fingers. If you set them so the setup gauge is in snugly, the fingers come out a little narrow. I had to do a couple of passes to get that right. Just don't make them too tight against the setup gauge.

Stick with it. It can be done and the results are excellent.


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## RichT (Oct 14, 2016)

> I have the DR4pro and have not noticed any issues (though I ve only tried it as a quick test)
> 
> - splintergroup


Earl did the D4 to D4Pro upgrade. I did the same upgrade. There is a difference between the D4Pro and the D4 upgraded to Pro in that the factory spacer for the tail board won't work with the upgraded jig. You have to mill your own.

That's what Earl is running into.


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## EarlS (Dec 21, 2011)

I read through the upgrade instructions until I saw the finger adjustment details and quit reading, never realizing that the answer was right there. Sometimes you can see the trees for the forset.

Thanks for the responses.


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## pintodeluxe (Sep 12, 2010)

> However, the spacer that is called for in the D4R Pro instructions leaves the tail board offset too far
> 
> That spacer won t work. You need to make your own per the upgrade instruction sheet I link to below.
> 
> ...


Talk about a spot-on specific response. Wow, this is what Lumberjocks is all about. Nice info share here.


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