Help with correct diameter for a timing belt project

[element 79]

Hello, I'm building some equipment that has a drum driven by a timing belt. The drum is roughly 11.25" in diameter. The drive belt used is H pitch - 1/2" spacing between the teeth. For the gear teeth on the drum I'm using another belt of the same pitch, inverted and epoxied onto the drum. The teeth do not match up end to end perfectly around the drum at this diameter (36 10/16" inches around measured at the top of the teeth) I've been removing teeth and reattaching with epoxy in the correct position and have it to where it almost matches up but after one revolution the drive belt is off just a bit. I'm afraid the drive belt is just going to jump over. Is it possible to adjust the teeth on the drum this way to make it work right? Or if I was to shim up the drum teeth, what would be the next best diameter of the drum to get a correct mate or can it even be done using the same pitch belt for both drum gear and drive? Thanks for helping.

 

[Bandit127]

You haven't had a reply yet so I will give an amateur's answer.

I think you need to modify the drum so that it has a circumference divisible by 0.5" (the pitch of the teeth in the belt).

 

[256bits]

Maybe this will help you.
http://www.gatesmectrol.com/mectrol....cfm?file=Belt_Theory06sm.pdf&folder=brochure

Notice where pitch diameter is measured on the belt and pulley.