Here are two pictures of my waving Elf Project. This is a carryover project from 2002. I
used the same 12 vdc 6 rpm  gear motor from my other projects.I get them from
Electronic part # DCM-164 cost $12.There phone # 1-800-826-5432.
These picture show the difference between waing position.I used anything I could to make the
frame.This was one of my demo elf arms. The first one was the Hammering Elf which ended up being
used all month for 2002 Christmas Season.  
The crank arm with some relay mounting track.I used the
relay mounting stuff because it was handy and it had holes
already.It was good for making  adjustments.But wears
very quick.
He you can see the motor shaft is bolted to the crank
arm.Which is just some angle with a square hole in it. I
made the hole by drilling ,then filing the corners out.
I made most of the parts out of a sheet of 1/8" flat stock I
had laying around.I didn`t really clean it up as you can see.
So more crude looking craftmanship.
I ran it for a couple of hours with no problem. My Elf are light weight so this material  works fine for me.If I were
to build something bigger I go with  steel and welding.