OnShape Sprocket Generators

Does anyone have a good recommendation for a good Onshape sprocket generator that is easy for a CNC to cut out? For an offseason project we are planning we need a #25 sprocket for a shooter turret. Any help is appreciated.

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https://cad.onshape.com/documents/08c7750efd66c84d0ccc5a2c/w/2a7cbb9ee63773879ef910d6/e/0d46c62da15fde2bcad499a3

This is what we used to make a sprocket for a turret

MKCad. Insert it as a derived part. Never CNC’d one though, but it is a standard sprocket profile.

image

I can’t speak for the sprockets but the pulley generator doesn’t make CNC friendly models. I ended up redesigning the tooth profile to be drilled by a drill.

That is your best bet, drill the valleys and then machine the rest with an endmill

@Chadfrom7226

Good to know for pulleys. We had 3D printed our 2020 turret pulley, so I’m now curious what we used back then for the tooth profile. @David_Bridge ?

@jago21 did you have any issues with chain fit on this generated sprocket? Did you sand the teeth to make a bevel at all, or did you just use a thinner material? Something like 0.90"? Would love more details.

Yes I made my own profile. Belt fits perfectly!

I was planning on making a CD post going into detail about how I made it

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I’ve used this featurescript before. Comparing it to the profiles of the Vex sprockets, basically identical other than the Vex teeth having flat tops and the FS ones being pointed. I haven’t actually made one in real life though, so I can’t promise anything. Unfortunately I don’t remember where I found it or who made it so I can’t properly give credit

We didn’t have any problems with chain fit. We machined the sprockets using a 1/4” endmill to rough out the shape and an 1/8” endmill for the final profile.

It was a while ago but I think we used .125 material. We then sanded the teeth with a belt sander to sort of chamfer them until we had a good fit. It was an off-season project but we would definitely use the process if we needed a non standard sprocket for a robot.