Finally wrapped this project up, after some setbacks.
To correct the angled chop I had to see what was the problem: the hole drilled in the chop or the hole drilled for the coupler buried in the leg?
First I tested the hole in the leg:
Clearly, the threaded rod exiting the leg is off of perpendicular. Then, before I attacked the solution, I decided to check the chop:
Huh. It’s off too! So, after some hand wringing, cussing, and a few beers, I took the case online and asked for help. I received a lot of good suggestions (thanks guys!!) from plugging and redrilling the chop hole to counter the downward pitch of the leg hole, to turning the bench around and drilling a new chop hole in the far left back leg (making that the new front right).
In the end, after some careful head scratching and lots of pondering, I decided to try and shift the angle of the chop hole. Since I was only talking a few degrees I decided not to fill it. That and I didn’t have any 5/8″ dowel stock laying around. Playing with the sliding bevel gauge, I hit on an angle I thought would fix things.
After a test piece on some scrap almost worked, I tweaked the tilt on the drill press table one past time and hit pay dirt:
That’s what I was after!!! A nice flush fit. Now. Just have to add a corresponding angle to the garter (oh yeah…redo that bit as well). In a shorter amount of time that I thought, I had it:
At last. Done! Well, sort of. I still had to make a new parallel guide. Which wasn’t too hard. I used a piece of 1/2″ oak and planed it to the right thickness to match the slot in the leg, then drilled holes for the pin (er, screwdriver) then mortised out a new slot in the chop, drilled a hole in the side for a locking dowel and reassembled everything. Voila!
This was a worthwhile project that despite having done it a year ago, taught me a lot about woodworking. My mortises were spot on this time, better than I’ve ever done. In all, I’m really happy how this turned out!