Reverse the Process...

Dunno why I didn't think of it before but it totally works so much easier.

I originally tried cutting thin slices of wood with available tools by locking the abnormal shaped in the vice and hacking away at it with the tenon saw. It's a bit of a sledgehammer for a pin type affair.

Last night it occurred to me to lock the saw in the vice and run the wood up and down it. Works an awful lot easier.