Live and learn.
(You probably have to have used an AKEDA jig to follow this.)
Long story short, snap the guides in from the bottom when cutting in the vertical position even though the manual implies that snapping them in from the top is OK.
Long story
I'm making some cherry ring boxes for the 10 ladies in our volunteer group who go out with us guys dong home maintenance for our elderly, less fortunate neighbors here in town. The gals aren't what I would call experts, but they get dirty, sweaty (OK, glowy), and paint-covered like the rest of the crew, so a bit of recognition/thanks was in order.
The boxes are going to use half blind dovetails to join the front and back to the sides - no reason, just wanted to do it that way. Set up the AKEDA, 1/2" 11 degree dovetail bit, and cut a test joint. Perfect fit, as usual with this jig, EXCEPT there was a gap between the side (tail) piece and the front (pin) piece. A noticeable gap! WTH? The tails were bottomed out in the pin notches, fit beautifully, but there's a gap between the pin board and tail board! No, I didn't change bit depth between the cuts, yes, the boards were 4 square, yes the boards were tight against the guide fingers before machining.
Got out the calipers and sure enough, the tails were about .020 longer than the pins were deep. That corresponded with the width of the gap; it would take a .019 feeler gauge, but not a .020. WTH?
After much thought I realized only one thing could do this. The tail guides had to be mis-positioning the tail piece in the jig (in the AKEDA jig the tail piece is machined vertically and is butted up against the bottom of the guide fingers). I checked the manual (OMG, read the manual?), checked my set-up, scratched my head. Finally I put a piece of 3/4 MDF in the tail piece post ion, up against the tail guides. I ran another piece of MDF in the horizontal clamp opening where the pin board would be machined, butted it against the tail piece and clamped it down. The vertical tail piece was .020 higher than the top of the horizontal pin piece! WTH?
Took the boards out and felt along the bottom of the tail guides where they clip into the adjusting bar. There was a noticeable difference between the bottoms of the guides and the bottom of the top horizontal clamp fence even though the guides were fully seated.
I had been snapping the fingers in from the top, pushing down on them to snap them in. I pulled the fingers out and flipped them over, then inserted them from the bottom, pulling up to seat them. Feeling underneath they now lined up with the top horizontal clamp fence. Inserted pin and tail pieces of MDF as before and they aligned precisely. Cut a test joint with the tail guides snapped in from the bottom vs the top. No gap!
Long story short, snap the guides in from the BOTTOM when cutting in the vertical position even though the manual implies that snapping in from the top is OK. Itis OK for horizontal mching, but not for vertical, at least not on my version of the jig.
I still love the AKEDA jig.