Half blind dovetail problems D4R Pro 24 inch jig

Hello,
I am trying to rout some half blind dovetails and am having problems routin g the pins.
Drawer sides (tails) are poplar. 1/2 inch thick. Drawer face is hard maple (pins) 3/4 inch thick. Bit depth is 7/16 inch.
I have 3 problems.
No matter how hard I clamp down on the pin board (top clamp). the torque fr om the router bit cutting through the end grain causes the board to rotate slightly screwing up the pin alignment. The pin board is about 8 inches wi de but I have a board of equal thickness clamped at the other end of the j ig to ensure even and correct clamp pressure. Light passes make no differen ce.
If I am lucky enough to get a cut that does not rotate while cutting the p ins,I see a second issue where the depth of the cut pin (from the side of t he board into the board not the actual bit depth) is LESS on the right side than on the left. I hope I am making sense here. I do not mean the router bit depth but the depth one routs the pins into the pin board so the tail b oard fits flush.
The pin boards are confirmed flat and the corners are at 90 degrees. Confir med with a engineer grade straight edge and square. The guide settings are for the tail board thickness (1/2 inch)
Finally, even if I can get past these 2 issues there is a fitting problem w ith the joints. At the left end of the joint the fit is good but at the rig ht end of the joint there is a 1/32 inch gap between the pin and tail board s.
The "left end of the joint“ is the side of the pin board that butts agai nst the end of the jig on the left side as one faces it.
I have destroyed some really nice wood and wasted days trying to figure out the cause. My frustration is at a point where I am coming to believe the p urchase of this jig was an expensive mistake.
If anyone has any ideas as to what could be causing these problems I would greatly appreciate any insight.
Dean
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On 1/13/2014 8:09 PM, snipped-for-privacy@mitfog.com wrote:

wider boards need more pressure but you can try adding some PSA sand paper to the clamping bar to help prevent twist. FWIW I have an older D4 but do not use a board on the opposite end to even out the pressure, I want the clamp to really clamp down.

Be ABSOLUTELY certain that the finger template is resting flat against the work!
1. The template is not flat against the work the entire width. Be certain debris is not getting between the template and the work. 2. The work is slipping on one end, see above suggestion. 3. You have a bit that is slipping. 4. Be certain that the template is parallel to the jig, make sure it is not adjusted further in on one side.

Becertain that the adjustable fingers are "tight" and not slipping.

My gut feeling is that your work is not being clamped tightly enough and is probably causing most of these problems.
Call Leigh and maybe supply pictures if the wood in the jig and the results.
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On 1/13/2014 8:31 PM, Leon wrote:

And just to add more to you woes.. ;~) Half blind dove tails are the hardest to get right. With ideal conditions the bit depth has to be set to it's sweet spot, regardless of what the book says.
Different woods will require different depth settings as softer woods tend to have looser fitting joints and harder woods tend to have tighter fitting woods.
The fact that you are mixing a relatively hard wood and relative soft wood may be a lot of your problem concerning fit.
Bit depth is crucial to a proper fit joint and that depth is the same for both cuts IIRC. Just remember if the fit is too tight you need to raise the bit a tough. Too loose, lower the bit a touch. And remember if the finger jig is not flat against the work this will change the depth of the cut.
I would suggest practicing on an inexpensive wood to understand how adjustments will affect fit and then move on to the more expensive woods.
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On Monday, January 13, 2014 6:09:58 PM UTC-8, snipped-for-privacy@mitfog.com wrote:

ing the pins.

What type of router are you using? All of these types of jigs require a sup er light hand and for the router to really remain flat and flow smoothly. O nce you have any clamping and alignment issue resolved you still need a rea lly light hand. I have found that the lighter (smaller HP) router you can u se the easier it is to just have that sucker move smoothly. Move as slow as possible.
Just to make you not feel so bad, I was able to get a Powermatic dedicated dovetailer and I have found many of these same issues where you really need to learn all the nuance, tweak the settings and be sure the clamping is wo rking well and use a smooth run technique. Luckily I wasted mostly Baltic B irch but did cut parts for 4 extra drawers when I did a run of 6 with solid Maple sides, backs and Cherry fronts and I needed all of them once I was d one. Maybe we should all get a hand saw, sharpen our pencils and chisels an d do it like Noah would have.
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