Key-Way for Gates Sprockets

[thefro526]

Originally Posted by philso

You can also try drilling into the "hub" part of the sprocket and using a set screw. Once the sprocket is in place on the shaft, drill into the shaft, about 1-2 mm, through the hole for the setscrew to give the setscrew somewhere to "bite". It is also possible to use two setscrews for added security. Make sure the sprocket is clamped securely when drilling. This is probably best done on a drill press.

We've used this method before on sprockets with varying degrees of success. It's not the 'right' way to do the job, but it will work - assuming you can keep the set screws tight at all times and that they don't slip. We've dimpled the shaft (Drill a small blind hole into the shaft for the set screw to fit into as stated above) and also done 'D' and 'Double D' shafts where a flat side or two is added to the round shaft for the set screw to ride on. Again, it's not the right way to transmit torque but if you're in a jam it will 'work'.

Broaching as stated above would be the ideal method, but requires semi-specialized tooling and a bit of skill/patience. Depending on your location, you may be able to find a local machine shop that's willing to broach the sprockets for you for little to no cost, from the few times I've seen it done, it doesn't take long at all.

You could also buy a hex broach (my preferred method of power transmission) and run hex shafts etc. Running hex does present it's own set of issues though, you'll need to find hex bearings, hex stock, etc, etc - and I'm not sure what the availability of those items looks like over your way.