Leigh D4R Pro pin board slippage problem

[Brad Lard]

I recently purchased a Leigh D4R Pro jig. Have been trying to get it calibrated to run variably spaced half blind dovetails in 3/4" soft maple stock. I first ran the tail board as instructed in the manual and all went well. Then moved on to the pin board on the jig top and that went well too, except that they needed to be a little deeper. So, I adjusted the depth and rerouted the same pin board. That produced a nice fit though a little loose from rerunning the same board.

I decided to practice one more time to make sure it wasn't an anomoly. Again I ran a new tail board and moved on to a new pin board. Since that time, I have not been able to rout the pin board without the front edge moving right, away from the front left stop. The rear stop stays in place mostly but the front moves as I rout left to right. I've done the following to try to deal with this:

1. tighten the pin board side clamp. At this point, it is beyond a simple thumb pressure as stated in the manual
2. add and also remove a 3/4" support out on the right edge of the fingers.
3. tighten the finger assembly tighter against the pin board.
4. tighten and loosen the right edge of the pin board clamp.
5. the manual says take 4-5 light passes and i've certainly done that. I'm also trying to just let the router do its thing rather than push it into the wood.

Nothing has worked. I'm sure I'm doing something wrong but have no idea what it is...

I appreciate any help.

[Malcolm McLeod]

I have had test boards move during initial setup and/or test cutting, but never during 'production'.

Generally, the problem occurs with a fairly wide work piece. I have always just tightened down the clamp opposite the workpiece. In some cases like this, there is a noticeable slant in the clamp bar to get even pressure across the workpiece, especially with narrower pieces.

I can't imagine wearing out the machined pattern on the jig surface that bites into the work, but is your jig new? Is the machined surface worn or damaged? Are the grooves clean/clear of any resin, glue, sawdust, etc.? In my experience, these ridges & grooves provide all the grip, the clamps and clamp bar just need to apply some even pressure - - exactly as per the manual. Hope this is some help.

[Brad Lard]

Thanks Malcolm. the unit is brand new and nothing is in the grooves. Was dealing with 3.5" wide boards when I started having the problem. Have included/excluded a board clamped opposite the workpiece. Same result. Who knows what i'm doing wrong, but it's dang sure clamped tight on the workpiece end.

[Al Weber]

I'd call Customer Support at Leigh. They have always been very helpful when I've had problems. I have always had to "overtighten" the bars to keep things from moving. Seems to be the nature of the beast.

[Malcolm McLeod]

I have had mine for 6+ yrs, so have forgotten a few things from my learning curve ... but I think my original efforts included placing a board on the off side to 'level' the clamp bar. And I think this didn't work. Seems like you've had the same experience.

It has also been several months since I used mine, so got it out last night and clamped a piece of scrap plywood about 5" wide x 24" long. I adjusted the clamp bar to give moderate but equal grip to the workpiece when it was placed on each side of the jig. This in effect levels the clamp bar. I then clamped the work piece on the left side as if to cut pins, then used the backward extension of the piece as a lever to try to move it - - and it will move.

I then cranked the right side clamp down 3 turns (no change to left side). This made it much more difficult to move the workpiece, even considering the leverage provided by the length protruding out the back of the jig. I cranked the right clamp down 1 more turn and tried again. I can still move it, but I have to try hard - again using the extra leverage of the back end - and it just barely moves. I can't imagine the router and bit could exert even close to the same force and so move the workpiece. There was a noticeable slant to the clamp bar at this point. (It took longer to type this, than to test the clamps.)

Long explanation - - but I'd recommend you just crank the off-side clamp down until things are solid.

[mreza Salav]

I was making some 40 drawers using prefinished birch and had that issue. Ended up using a sand paper taped (double side) to the clamping surfaces. Worked much better.

[Charles Lent]

The "Thumb Pressure Rule" is true, if you have a very strong thumb. An average thumb pressure is likely not quite enough. 1/2 turn of the clamps and maybe 2 fingers instead of the thumb to close it, will likely cure your problems. I've had similar problems with my Leigh D4R and this is what I've been doing. Maybe when I was 30 I could have done it with my thumb, but this tired 75 year old body can't do it any more.

Charley

[Brad Lard]

Malcolm, coincidentally after responding to you, I did the exact same thing.... removed the board from the opposite workpiece side and clamped that side down tighter and left the workpiece side clamp alone. It significantly increased the pressure it took to move the board although it would still move some but much less than before. Perhaps that's what I was missing though I didn't have time to try to rout anything. thanks for going to that effort.

[Lee Schierer]

With machine cut dovetails, you have to have the bit height set exactly the same for each half of the joint for a perfect fit. My jig has a note that says: "to tighten, heighten the cutter, to loosen, lower the cutter." This means in reference to the router base plate surface. Extremely small adjustments are needed and every change doubles the interference or clearance. I always run the router across to make the cuts and then to insure that I didn't leave any bumps or missed spots, I go back through all the cuts a second time. When I acquired my third router, I left the bit set up in the router to be perfect height for 1/2" thick drawer sides. If you don't have several routers, you can use a Wixey mini digital height gauge to measure teh perfect set up and get back there after a bit change.

[mreza Salav]

For sure don't use a "helper" board on the other side as it only makes the matters worse (less clamping pressure for the board you want to cut).