Conveyor belts

[Max Lobovsky]

We are looking to build a conveyor belt to transfer balls. I have found a variety of conveyor belting on McMaster-Carr, but I'm having a hard time finding appropriate rollers for the belting. Are any rollers of the right minimum diameter with decent friction acceptable? What about for belting that has only one high friction side? What kind of force can I expect to transfer to the belt (ie, how much tension per in will a given roller apply)?

Additionally, any advice on conveyor construction would be greatly appreciated.

Thanks.

[sanddrag]

Teams in the past have used several pulleys and small timing belts or several strands of this stuff called polycord rather than a full width belt.

[Rick TYler]

Here's an out-of-the-box idea. Instead of expensive conveyor belts, use high-quality commercial sanding belts. They are cheap, readily available, and can easily handle the heat and load of the little foam balls. The commercial-grade belts have a fabric backing, and if you use a fine grit belt (like 150 or 220) you get a high-friction surface that still grips when dirty, and will not damage the balls. I've tested a launcher built from two belt sanders and the balls didn't show any particular damage.

Other advantages are that sanding belts are light weight, available in a wide range of sizes from 18" in total length -- which means about 9" if you lay them flat -- to 93-1/2" in widths from 1" to 4" for common sizes, and up to 36" widths in some commercial applications. Did I mention that they are relatively cheap?

Some of the students on our team were worried about their durability. Trust me -- your foam balls aren't going to be as much strain as a 20-pound piece of rock maple.

I usually buy mine at Klingspor's shop.

[Madison]

Originally Posted by sanddrag

Teams in the past have used several pulleys and small timing belts or several strands of this stuff called polycord rather than a full width belt.

Does anyone know of any suppliers of polycord beside Small Parts, Inc.? I want to shop around some because $22 for a 10' length will get a bit pricey when you need the stuff in bulk.

McMaster-Carr has prejoin urethane belting up to 60" outer circle length for reasonable prices, but I was hoping for something longer. Urethane is not as easy to join as polycord, apparently.

[Raul]

Originally Posted by M. Krass

Does anyone know of any suppliers of polycord beside Small Parts, Inc.? I want to shop around some because $22 for a 10' length will get a bit pricey when you need the stuff in bulk.

McMaster-Carr has prejoin urethane belting up to 60" outer circle length for reasonable prices, but I was hoping for something longer. Urethane is not as easy to join as polycord, apparently.

M,
Try this McMaster part number - it comes in continuous lengths that you join to make the size you want:
59725K14