pic: Offseason Drive Train Progress

[AdamHeard]

If you have a manual mill, why not do the holes on that?

Originally Posted by JesseK

Thanks for the heads up about the sprockets Austin. They're 16T since their PD creates to a nice round circumference, and I was wondering if 22T is preferred over 16T. Nice round circumferences make nice round distances between axles, so the chains will not need tensioners. If we need to take out slack, we'll use half-links. We ran tensionerless after DC this year (1 regional, 1 champs, 1 offseason event) without a single issue. On the same note, are the AM 7075 Aluminum sprockets strong enough for the drive train? What's in the CAD is steel, with the full hub. They're a nice round 1/2" wide in total, which simplifies the spacers as well; yet if the AM's have strong enough teeth, then I see no reason to stick with the steel.

Actually, if you have the same toothcount on both sprockets, it doesn't matter what their circumference is the exact center to center is still a clean number.

There is also a helpful excel called Dr. Joes chain path calculator for all other situations.

We've run AM 22T for seasons without any issue.

[AustinSchuh]

Originally Posted by AdamHeard

We've run AM 22T for seasons without any issue.

971 ran them last year, and had no issues. They are quite a bit lighter. But, they are a lot more expensive than steel. Your call there.

I personally won't put a chain run on one of my robots without some sort of tensioner, but if this has worked for you in the past, then go for it. I know that 233 has run 25 chain without tensioners, and it has worked for them.

[artdutra04]

Originally Posted by AustinSchuh

971 ran them last year, and had no issues. They are quite a bit lighter. But, they are a lot more expensive than steel. Your call there.

I personally won't put a chain run on one of my robots without some sort of tensioner, but if this has worked for you in the past, then go for it. I know that 233 has run 25 chain without tensioners, and it has worked for them.

We also used 22T 25p 7075 aluminum sprockets in our drivetrain this past year without any problems, but we ended up machining them ourselves from 1/2" 7075 plate (which was cheaper than buying steel sprockets). We designed for initial exact chain length, but needed to add tensioners as the chain stretched. For that, we ended up just throwing in some of our Lexan floating idlers (which are quite possibly the lightest possible roller chain tensioner ever), and they worked without any problems.

[JesseK]

Yea, we're considering the price difference between the steel and aluminum sprockets; $7 vs $16 is a big difference for 16 sprockets (prototype+production).

We actually got some help from 233 in DC to make our chains tensionerless this year. They put alot of emphasis on proper spacing for the chain. We may try to pre-stretch to an extent as well. Maybe we'll also have some Teflon ready in case we wind up needing tensioners.