Mike...
Because both joint elements (pins and tails) contain both "inside" and "outside" arcs, we'd produce a shape mismatch between tails and pins. If each element contained only "inside" or only "outside" arcs, then your shortcut could be used to good advantage.
There are two other (completely independent) considerations that contribute to making joinery on the ShopBot "interesting":
The first is step resolution - there is no way to, for example, accurately split 0.001" (or even 0.005") on the 'Bot.
The second comes into play because each tail, and each pin, is located with a single reference point and all other points in that tail or pin are computed from that reference point and each point is computed relative to the preceeding point. This, in combination with the fact that the ShopBot control program uses a low-precision floating point format, requires that, to avoid unacceptable cumulative errors, I perform those computations outside the ShopBot environment using a higher precision floating point format.
I discovered this when I observed a difference between geometrically identical toolpaths produced by PartWizard and those computed (using sine, cosine, and tangent functions) within an SBP program.
All of this together means that the "glue gap" value needs to be examined and either applied to just one of the joint elements - or (perhaps unevenly) split and applied to both tails and pins.
And no one is likely to specify a gap as large as 0.01" unless they plan to grout/spackle the joint.
In any case, it's a "solve once and forget" kind of problem - it just introduces a bit of complexity to the development that I hadn't anticipated.
...Morris
