Thread: Chisel/chain mortiser question - Help figuring out how to install chain sprocket

Welcome to the forum.
You should get some good advice along the way.

Do you have a pic of the Sprocket? you should have a different size Sprocket for each chain size.

I have attached a couple of pics of parts from my Wadkin.

1) 3/16 Sprocket
2 Washer/Collar

On the Wadkin the Collar pushes tight up against the chain when tightening, also there are different size spacing Collars to align the chain and act as off-sets.
Sprocket 3-16.jpg Collar.jpg

Thanks Camelot, I have a few different sized sprockets matched to their chains. It's the collars I've never seen and don't have any of. They shouldn't be too hard to source or make. Obviously the collars have the groove in them to slide over what I imagine is some kind of key steel, but what does this key steel look like? Do you have a photo? Also are you able to show me the collar and sprocket installed on the arbour?

My modified key steel works. In fact I have just finished mortising fourteen 150x150mm hardwood posts with 3 through mortises on each for a 3 rail fence, but I'd like to know how it's supposed to work. I'll attach some more photos of the my modified key steel and try to clarify why I'm having trouble picturing how the collars work.

Thanks again for your reply, I really appreciate it

I recently bought 2 Wadkin MF's one complete & the other missing parts and I am looking to repaint both of them, so I have not used the chain yet, however when I took the nut of the shaft to take a pic for you I noticed the key is missing (on both machines).

So the collars you have missing would slide on first (if needed to align the chain) and then the Sprocket with the keyway slot (notched on one side only like the pic I posted) facing the machine.

Your Sprocket design could be different than Wadkin, in that your Sprockets could have keyways running their full length and then the collars would go on after the Sprocket (as well as before (if needed)) and the key would need to terminate within the thickness of your collar(s) thus allowing the nut to be tightened without hitting the key, because the key would be hidden by the collar.

Cheers for the info. My sprockets are also notched on one side only. I contacted a mate who has a chain mortiser and he's going to send me a picture of his key. He reckons they're a bit different than what you'd expect in a key (notice how the key slot in the arbour/shaft is fairly wide but the notch in the Sprocket is narrow). I'll post it here when I get it in case it ends up being useful to anyone else.