Machining Gears/Sprockets On CNC Router

Hi All,

Do folks have experience trying to make their own plate sprockets or gears on a router?

What is your preferred source for the model?
What size cutting tool do you use?
Are you able to cut small #25 sprockets, or only #35 ?
Do you create a toolpath to taper the face of the teeth, or do you just grind/sand that down later? Or, do you leave it as is for a thin enough material?

What are the different tooth sizes of sprockets or gears you’ve been able to create and use?

For reference, we are using an Omio X8 and currently only have a small variety of cutting bits.

@RoboChair @AdamHeard

Thank you,

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You can definitely cut #25 sprockets but you need to wear them in based on material thickness. Not sure I’d put a big load on them though? We’ve done this for a turret once. The tapering was done with a file after and then just running it in with a decent amount of lubricant.

We also did a 12DP geared turret once as well. That worked too… don’t recall the bit it was cut with but it was small and took a decent number of passes. Also did a fair amount of wearing it in before running it on the robot. Didn’t take much though… hundred-ish rotations. Turns out in the battle between a steel gear and an aluminum one, the steel one wins over time.

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I’ve cut #25 sprockets. Didn’t do any tapering and just let it run itself in a little bit. Held up fine in a pretty high load situation (6 KW going through a 80+ tooth sprocket on a 6" scooter wheel)

Any specific model you used? I ask because I’ve heard people prefer sdpsi’s models for some reason. What size end mill worked best for the tooth profile?

I just used Vex’s sprocket Cad file and projected the tooth geometry onto my own design. I can’t quite remember what size endmill I used, though it probably was an 1/8".

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Cool that was essentially my plan.

Any experience cutting gears? I was mostly thinking plastic ones with larger teeth for some random mechanisms.

I don’t think it’s worth the effort honestly unless you want to end up with the kind of gears that you’d stick on your refrigerator when you were little. I’d stick with sprockets and 3D printed timing belt pulleys, you can always machine a metal hub for the pulleys if you need additional strength.

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Actually, thinking more along the lines of 4613’s arm rotation from 2018. Looks like 2102 used the same type of gear profile but I just couldn’t tell what size teeth.

During the off season we had we created a version of 221’s double sprocket (#25), but it was done by one of our sponsors/ mentors outside of our build space (no access to machines during off season really). They have run fine but we havent ran them through a season.

We are talking about a rack for a rack and pinion, since the teeth profile came out a little rough on a waterjet (partially due to rush job and no gear with sponsor to compare teeth profiles).

I wouldn’t be surprised if they used something like the Matthias Wandel’s Gear generator.

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