Help with my Leigh D4 DT jig

[Chris Livingston]

I’ve had my Leigh D4 Dovetail jig for about 2 years and have been fairly happy with it but for the last three days I have been banging my head against the wall trying to do some simple half-blind dovetails for 2 drawers.

The fronts are 55/64th and the sides are 11/64th (yeah I know funny dimensions but I wanted to keep them as thick as I could). I started by using the 101 cutter set at 5/8th but the joint was too loose so I lowered it a bit. The problem is at just over 5/8th the cutter is buried below the edge of the wood and makes it really tough to cut using the shaft so I switched to the 80 bit. Again at ¾ the joint was too loose so I lowered it bit by bit until the joint was tight but there was only about 1/16th left from the front of the board.

I then tried switching to the ½” shank 90 and 100 but the fit was loose no mater what depth I went to. I thought it was my old PC 690 router and the base I could never quite center so I bought the new Dewalt 618 series router with the 3 bases as well as the actual Leigh “precision” guide bushings to no avail.

Thinking back I have never been able to set up the fingers for half-blind routing and just flip them over and get a perfect fit. One time I had to re-set them all closer together in order to get the sockets to fit the tails I had cut.

What am I doing wrong? I am not a moron when it comes to this kind of thing but I’m beginning to feel like one.

Any help is appreciated.

Chris

[Jim Becker]

'Can't use the #80 bit for half-blinds, I believe. I pretty much always use the #120 for half-blinds.

[Chris Livingston]

In the manual the 80 is the first one in the list of half-blind bits

[Jim Becker]

In the manual the 80 is the first one in the list of half-blind bits

True, I didn't consider carefully how thick your material is. Dimention "B" for the #80 states that the working depth is 3/4" which "should" be ok for your application if you are comfortable with how close to the "front of the drawer front front" you will get. 55/64" is .86". Try minute adjustments of where the guide fingers are located on the scale, I find that I sometimes need to make very slight adjustments, even for different species, to get half-blinds "just right tight".