The chain for my Weeden #646 doesn't seem to fit well. The chain itself seems like the proper design but doesn't match up to the wheel's teeth, it is just slightly offset on the teeth. It is also a bit loose so it tends to come off.
On Frank's site for Weeden parts there was a link to
Carol and Dallas' Antique Toys where Dallas sold Weeden roller chains, the only source known. I had emailed Dallas a few times but found on a Google search he sadly passed away late last year. While the website is still up, it is unlikely the chain can can be bought.
Might anyone have bought a few from this source and have an extra they could let loose of?