DJ Delorie wrote:


A couple of thoughts...

To check how much you have to lower the dovetail bit, pull the two
boards apart as hard as you can, and use feeler gauges to measure the
biggest gap. Lower the bit that much(*).

Yep, that's what I've been doing.

I use a 1.5hp (yea, right)
PC router with the fixed base, and I've calculated how many thou each
tic on the ring represents so I can do this "accurately" (again, yeah
right).


The Colt is a little more fussy setting depth, but I had the same issues
with the 1613 EVS with the microadjust.


Beware of cupped boards.

Will double-check, but I'm very fussy about getting both flat and square
stock.


I always do two corners at a time, one on each end of the jig. Not
only is it faster, but it keeps the jig squarer to the boards. At
least put a spacer on the other end, using one of your other milled
boards.

Have been putting a spacer on the other end to make sure


Yes, your router base should be flat. Compare it to some reference
flat, not to the jig. I got a cheap granite surface plate from
Grizzly for this purpose.


That seems to be the next action I need to take. I know for certain the
router base on the Colt is not flat. I can't speak for the one on the 1613
when I used it last time.


Don't rotate the router when routing - hold it in a fixed orientation
throughout. Consistency is more important than concentricity.

After considering this, I think it is also necessary to rotate the router
180 degrees when doing pins vs. tails. When you look at where the router
bushing contacts the jig, it seems that you want the same point contacting
the jig for both pins and tails. To do that, the router needs to be
rotated 180 degrees. Would you concur?


When I do through dovetails for batch jobs, I do all the tail boards
first, then all the pin boards, and it doesn't matter which tail
boards I match up with which pin boards - all the joints are the same.
The D4 *can* make accurate joints, so keep working on it.


That's good to know. I'm still struggling with whether this is setup or
technique.


(*) If that's way too tight, next time do half the thickness, I lose
track of when the adjustment doubles the results and when it
doesn't.

--
If you're going to be dumb, you better be tough