Bicycle sprocket

[Mikey]

I am new to this site, but I like the idea that I can draw the design specs using the emachineshop software, and then have them fabricated. The question is:

Is it pretty easy to make like a 2" by 2" by 24" rectangle like piece that basically can drive a bicycle sprocket? The piece would basically have holes in, so that I can drive my bicycle sprocket instead of using my bicycle chain.

Thanks in advance

[Tech2]

Please clarify what you want.

[Mikey]

Sure, let me see if I can elaborate more. Basically I want to know if it is easy to use emachineshop software to draw and design a rectangle like part with dimensions of 2 inches by 2 inches by 24 inches that will have holes in it on the top and bottom where two bicycle sprockets will driven by the holes in the rectangle part. I hope that makes sense.

[Tech2]

Perhaps someone else understands.

[Stuart-Grant]

What it sounds like to me is he wants a 2x2x24 rectangular bar with a bolt hole pattern drilled into the 2x2 face on each end. He would then bolt his bicycle chain rings to the bolt circle. I imagine this is either for a trike setup or as some sort of power transfer device just using bicycle components.

OP, yes this should be easy with just about any modeling software, though I have no experience with EMS as of yet. What you need to do is find out what bolt hole circle you need to use and then figure out how to draw a circle.

Also, most bike chain rings use a bolt hole circle of around 120mm if I remember correctly, though some mounting bikes drastically reduce this diameter, meaning that your bolt hole circle would 4.7" approximately requiring at least a 5x5 face once you add material for the radius and major diameter of the threads.

I would go about making two parts, one which adapts the bolt hole down to a smaller diameter for power transport to the other end, and a smaller shaft to run between the two. Unless you have experience with figuring out which direction torque is going to be applied I would use a key on the shaft to hold the adapters on which is then held tight with a nylock nut, because if you just have the adapters thread on one may come loose under load.