# Chain drive weapon woes
**URL:** https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804
**Category:** Questions & Help
**Tags:** featherweight-13-6kg, building
**Created:** [29 September 2026 20:23 UTC](https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804 "2026-09-29T20:23:25Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@fopsy](https://forum.bristolbotbuilders.com/u/fopsy)
#### Post date: [29 September 2026 20:23 UTC](https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804/1 "2026-09-29T20:23:25Z")
Hello!
I’ve been messing around with the idea of making a scooter motor driven flipper. But I’ve spent the last few days really struggling to figure out a way of connecting said motor to a sprocket, a sprocket to a shaft/axle. The sproket on the motor is a 9 tooth 410/#40 sprocket, got a 410 chain, and every sprocket i’ve found out there are all imperial measurements.
I feel like I’m going mad presently trying to figure out how to essentially create a shaft, with a sprocket, that can either drive a bar to lift a hinged flipper or dirently as the flippers pivot axle.
Any advice, questions help would be massively appreciate! Save my sanity!
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### Author:  [@Strang\_H](https://forum.bristolbotbuilders.com/u/Strang_H)
#### Post date: [29 September 2026 20:43 UTC](https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804/2 "2026-09-29T20:43:09Z")
410 chain correlates to BMX sprockets, you could look into using one of those and studying how they interact with the hub, or even using a crank-side sprocket and using a BMX crank as the first part of your lifter arm
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### Author:  [@fopsy](https://forum.bristolbotbuilders.com/u/fopsy)
#### Post date: [29 September 2026 20:49 UTC](https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804/3 "2026-09-29T20:49:06Z")
I don’t know why I didn’t come here days ago! A BMX sprocket, like you said BMX crank would actually work perfectly! I honestly didn’t know 410 chain was BMX chain I feel like an right flapjack 😃
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### Author:  [@Strang\_H](https://forum.bristolbotbuilders.com/u/Strang_H)
#### Post date: [29 September 2026 21:09 UTC](https://forum.bristolbotbuilders.com/t/chain-drive-weapon-woes/804/4 "2026-09-29T21:09:05Z")
Only able to help cause I got stuck in a similar spot! Hope the build goes well 🙂