HTD Belt Pulleys

[m5burndt]

Hi all, Team 4256 here.

Our team would like to stick with the belt system supplied with the KOPS, However, for volume reasons, we would like to use the old Andymark CIMple boxes instead of the larger Tough-boxes that came with this year's KOPS.

This is convenient because they both have the same 1/2" keyed output shaft.
HOWEVER, the CIMple gearbox has a reduction of 12/56 or approx 5:1
Whereas the KOPS toughboxes have approx 10:1 (per 2013 drive system specs on andymark site)

We could simply fit the pulley on the shaft, but because the CIM boxes don't reduce as much we would be zipping around at somewhere near 29 ft/sec (waaay to fast to be controllable)

To maintain the same overall drive ratio with a controllable speed, we would need a pulley with about HALF the teeth of the pulley used with the Toughbox. I am having a hard time finding another pulley that is the correct pitch/width, bore size, etc.

[GDG 2337]

try these

http://www.sdp-si.com/

http://www.econobelt.com/

[m5burndt]

Thank you! That pretty much solves my problem. I was looking on Mcmaster-Carr before I posted and couldnt find anything.

[m5burndt]

One more question, we are looking for about an 18 tooth HTD-5 pulley with 1/2" bore. Econobelt has them but the biggest is .2500" keyed bore. Would you happen to know if these pulleys are solid aluminum or if they are hollow on the inside? (We hope to bore-out to 1/2" ID, obviously this is not possible if the pulley is a hollow finished-bore)

Thanks again,

James

[KrazyCarl92]

You could also use 4" wheels instead of the 6" wheels from the KOP to get a more reasonable combination of speed and force. You may need to consider other factors along with this decision, such as ground clearance for frisbees beneath the bottom of your frame, but this may help provide more options if you can't find the exact pulley size you'd like for a 6" wheel.

[Chris is me]

The pulleys are solid aluminum. We've machined our own bore into them many times before.

[DonRotolo]

Originally Posted by m5burndt

(We hope to bore-out to 1/2" ID, obviously this is not possible if the pulley is a hollow finished-bore)

The manufacturer often provides info on the maximum sze you can bore out a given sprocket. Look on the Gates site for that data.

Also remember that you need a certain amount of belt wrap for that 18 tooth sprocket to not slip. Slipping even a little bit will cause your belt to self-destruct in a few seconds.