Trapezoidal Type Pulley (timing pulley)

[DavidB]

I'm trying to find out more info on the tooth profile for a trapezoidal timing gear. (Gilmer Drive)

Can someone please help with any info?

 

What I have is a timing belt which has .375" pitch and I want to make a few different diameter timing gears. I want to make a form tool up so I can cut each valley in one pass.

I'm looking at doing these on a Lathe with C-axis and live tooling.

 

These pulleys are for an engine I'm building (pic attached) made from Alloy. I want to increase the diameter of the crank and water pump pulleys.

 

Any help appreciated

Cheers Dave

[#Rekd™]

Try a Google search on Synchronous Sprockets.

[DavidB]

I have been searching but I cant find any detail on the gear profile. I think it has 40 degree sides, but Im after the width abd deepth of the profile so I can make a tool up.

 

Cheers Dave

[Guyinthedesert]

Have you tried the Mark's Standard Handbook? I'll look it up, if and when I ever get home and see. I'm sure it's there.

[DavidB]

^^^^Never heard of that, I'll check it out.

[mkd]

wonder if the belt mfr would be of help?

[Bridgeportboy]

http://www.gatesmectrol.com/mectrol/popups/LinearPitch_Imperial.htm

[Bridgeportboy]

Piccy from link above.

 

Steve

[DavidB]

Thanks Steve I'm wondering how deep the groove in the gear would be?

[Guyinthedesert]

^^^^Never heard of that, I'll check it out.

 

I'm surprised. I've never run accross anything that wasn't in the Mark's handbook, but not a word about link/ timing belts. My copy is pretty old, but link belts have been around for a long time. Huh? I'd take a look and download the patent. That'll give you the calculations for the teeth

[#Rekd™]

Look through the images here.

 

https://www.google.ca/search?q=Synchronous+Sprockets+photos&client=firefox-a&hs=Qer&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=bbbKUoTQG8ii2AXM4oHoCQ&ved=0CCwQsAQ&biw=1206&bih=736