I ordered the four sprockets (two drive sprockets and two idler sprockets) from eBay last month, and they finally arrived today. However, they were completely unsuitable. The drive sprockets don’t have set screws, and the idler sprockets are asymmetrical.
Where do you guys get your sprockets from?
The ones we use are custom made because I couldn’t find any that were quite right
In that case, is there any chance that I can buy a set from you?
We’re trying to figure out how to walk the line between selling all the parts one at a time to make it as easy as possible for everyone to build CNC machines, and really needing to sell the whole kit to be able to pay to keep the lights on. We’re going to be adding the chains to the store really soon, and I’ll see if we have enough sprockets to put them up too, but if we become a piece by piece online hardware store we’ll go out of business pretty quickly 
Can you drill and tap some set screws to make the drive sprockets useable?
Look on this page for item # SPR-2511A. It’s an 11-tooth sprocket with 2 set screws and an 8mm shaft hole. There is a setting in GC for number of teeth, so the fact that this isn’t a 10-tooth sprocket won’t matter.
I’ve never bought from that company, but it might be worth checking into.
@blurfl Thanks for the link. Those might do nicely. Do you think that something like # SPR-2513C might work for the idler sprockets or would the corners of the dual d-bore bind in the s-hook?
How about these? Would 16 teeth have a detrimental impact on the performance of the machine?
Generally speaking, the more teeth you have, the less resolution you will get. But this is a bit of a moot point given our encoders are before the gearbox. From what I remember, the resolution is pretty high with the stock setup. I have a set of 25 tooth steel sprockets I got from ebay that I’ve been meaning to test to see how having more teeth would affect accuracy.
The flipside, however, is that with more teeth you’ll have a higher max feedrate! Right now the machine is limited to about 1000mm/min, or 40 ipm. This is uncharted waters, though. Not that it should have any detrimental effect, but we haven’t tested anything but the standard 10 tooth one.
The d-bore would cause trouble. You could file it round, or fill it and drill a center hole. Or use the sprockets you have that don’t have set screws…
The 16-tooth ones would work,too.
You might be able to glue the gears on, with this and the appropriate primer
I would never glue gears on, too many possible reasons to remove them at some
point in the future.
There’s removal instructions in the product off but they’re not readable on this phone. Heat, acetone, Loctite’s magic solvent, seen a sharp rap with a hammer suggested. Probably a small gear puller would help, maybe one for battery posts. Loctite does consider removal, otherwise everybody’d just use epoxy.
I used the predecessor, called “Secures Gears” on farm and household item repairs years ago but don’t recall ever trying to remove anything. Old-timers.
The product is rated for 4000 psi iirc, didn’t try to calculate if that’s enough to handle a 66# pull at the outside of the pulley.
I wound up ordering these:
and these:
Sold out… I ended up ordering the parts referenced above + the d-ring idler from electricscooterparts.com.
I plan to grind/file the bore round.
the standard motors are 8mm shafts
Do anybody have drawing of the sprockets?
Just an update for anyone looking for 10 tooth 8mm bore sprockets, I got mine for $2.69 each on Aliexpress.
1pc 8mm Bore Pilot Motor Gear Roller Chain Drive Sprocket 10 Teeth 10T Metal Sprockets with High Hardness