Quote:
Originally Posted by MICHAELABICK
In preparation for next year, team 1836 and 1515 are collaborating, and thinking of using belt. We were thinking of using gates belt, specifically the GT2 belt, as we have heard of many teams using it, and because we can get it free from gates through the FRC kit of parts coupons. We were wondering though, what pitches have other teams used. We are specifically thinking of using 3mm pitch belt. Would this be to small of a pitch. It it is, would 5mm or 9mm pitch be ok?
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While the order page is currently closed for the season, the free Gates belts are all 5mm pitch, HTD profile belts.
While GT2 is a better torque-carrying profile than HTD, I've used 5mm pitch, 9mm wide, HTD profile belts* on multiple FRC robots since 2009 without any problems. The most important thing for smooth operation of timing belts is to ensure they are properly aligned and tensioned. I try to avoid the need for belt tensioners, and always
design for the exact center-to-center distance.
The nice thing about using 5mm pitch, 9mm wide, HTD profile belts is that SDP/SI has a great assortment of polycarbonate timing belt sprockets with aluminum hubs that make for some really lightweight (non-drivetrain) mechanisms. Just pay careful attention to the dimensions in the product spec sheet, as the size of the inner aluminum hub varies depending on the number of teeth. It is possible to crack some of the smaller sprockets (usually less than 20t) if you get to aggressive on drilling out/broaching the stock bore ID. For those sizes, I prefer to use either COTS aluminum sprockets or custom machined from timing belt pulley stock (also available from SDP/SI).
*To me, having one standard belt pitch/profile in the shop was more important than using some GT2 components and possibly having it get mixed up with free Gates HTD parts. To me, if the application needs something stronger than the "standard" size timing belt, then I use roller chain or 20DP gears.