Another question for Steve Maskery

[Grahamshed]

Hi Steve.
I posted recently about my version or your finger joint jig and the joints being to tight.....
Tightening the adjustment screw worked a treat but I then had trouble cutting fingers in plywood which I have solved ( I think ) with a spiral uncut bit. New bit, despite being the same 8mm tightened the joints again so I adjusted the screw again ( is this getting boring yet ? )
I now get beautifully fitting fingers but have lost the alignment on the edge of the wood by about maybe 1mm.
I cannot work out what would cause this. Can you ?

 

[Steve Maskery]

No I can't. It should be flush, no matter what. The first cut is made with the workpiece up to the peg, so that defines the width of the first finger. Then that is turned round, so it is still exactly the same width, and the first socket should be cut to exactly the same size. I don't see how it could be any different.

You are assembling it with the reference edges to each other, aren't you?
S

 

[Grahamshed]

I am.
I thought perhaps I hadn't pushed the first piece up against the peg properly so tried again but with the same result.
I will have another go tomorrow and see if I can pin down what I am doing wrong.