# I need help making a slip gear

I’m trying to make a slip gear for my robot but idk how to do the math to make one. The picture below shows the gears I’m using the bigger one will have my arm attached to it and my motor is on the smaller one. My arm needs to move 63° before rubber bands pull it up to launch. Can someone please show me the exact amount of teeth I need to grind away that would be really helpful for me.

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I am unsure of the exact mathematical solution to your problem, the way I would approach it would be to measure 63º on the large gear mark it with a Sharpie, and then run the small gear along the outside making the tooth you start and end on with Sharpie and grinding down those teeth ( Always shave down less than you think you need you can always shave more off kinda hard to add them back on). If the gear you are shaving is the smaller one then I would do the same as above just flip them around. Hopefully, this makes sense let me know if you need clarification and if it works!

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Even if you did know how to do the math, you’d still do what every veteran team will do: grind off 4 or 5 teeth to get started and see how it works…then take of more until it’s doing what you want it to do. You can always remove teeth, but you can’t put them back on!

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For anyone curious about the math. You take the number of degrees divided by 360 times the number of teeth on your gear, and keep that many teeth on the slip gear. Though as mentioned by others, you will probably want to shave 1 or 2 less teeth, you can always shave more teeth, you can’t add more teeth later.

For this example:
63/360 * 84 = 14.7
Therefore you need 14.7 teeth on the slip gear, but I would try with 16 or 17 first and shave more off as needed.

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It worked with flying colors I got the exact amount of range of motion that I wanted thank you.

@Maddox_Heaton No problem, happy to help!