Need for Aluminum Gears and Sprockets?

[sanddrag]

I could have an interest for ANSI #25 7075 Aluminum sprockets in the range of about 18 or 22 teeth, with hub, and 3/8" round bore (to allow expansion up to several different bores).

[R.C.]

So I take it that there is a need for sprockets. I'll start the list of things asked for. Just add on to it.

1. ANSI #25 7075 Aluminum sprockets in the range of about 18 or 22 teeth, with hub, and 3/8" round bore
2.
3.
4.

[AustinSchuh]

Originally Posted by sanddrag

I could have an interest for ANSI #25 7075 Aluminum sprockets in the range of about 18 or 22 teeth, with hub, and 3/8" round bore (to allow expansion up to several different bores).

How thick should the hub be, or is there some standard hub size that I am not aware of?

[Cory]

Originally Posted by CraigHickman

Hate to be a bubble burster, but this would put material costs way up. In order to have a hub, you need round (or square) that is greater than the outside diameter of the sprocket. If you have no hub, then it would be simple to machine it out of plate. If a hub is really needed, then why not machine a nice little 6061 spacer and bolt it to the flat sprocket? It'll end up costing you less in materials, and can easily be done on a manual mill...

Craig, I'm not sure what you're referring to. You can make a hubbed sprocket out of the same size barstock as a non-hubbed sprocket.

As to whether or not I'd be interested-sure, in a year or two.

I mean no offense to whoever would be making these, but it's too much to rely on a party that is a quantity unknown to FIRST. We have no idea if this guy can handle hundreds (or thousands) of parts in a matter of a week or two. We don't know if he can guarantee that every part from every batch will meet a consistent quality level (precision, accuracy, fit and finish, etc). We don't know if the price will be right (and if it's custom, you're almost totally screwed if the budget rules remain the same. It would be prohibitively expensive to have to account for fair market value of the labor involved). There's too many unknowns for me to be willing to plan my drivetrain around the expectation that these components can be purchased COTS.

There's a lot of thought and planning that needs to go into something like this. RC, I would encourage you to talk to Andy or Mark and they could fill you in on how much work it is. I'm just worried that your sponsor may think he's going to be doing a couple parts here and there and not really understand the magnitude of such an undertaking. He may not realize that he could be on the hook for 1,000 parts that teams will be expecting to show up at their door within a week from the time they place the order.

Just with the knowledge of the processes involved, you could tie up a large sized shop for most of the 6 weeks fabricating all the various sizes of gears and sprockets. More, depending on the machines they have.

I'm not saying you shouldn't do it, but I think you should step back and take a look at the big picture, or find someone who can help you do so. It would be a shame for teams to be relying on this venture, and have it fold mid season because it turned out to be way harder than expected.

[R.C.]

Originally Posted by Cory

Craig, I'm not sure what you're referring to. You can make a hubbed sprocket out of the same size barstock as a non-hubbed sprocket.

As to whether or not I'd be interested-sure, in a year or two.

I mean no offense to whoever would be making these, but it's too much to rely on a party that is a quantity unknown to FIRST. We have no idea if this guy can handle hundreds (or thousands) of parts in a matter of a week or two. We don't know if he can guarantee that every part from every batch will meet a consistent quality level (precision, accuracy, fit and finish, etc). We don't know if the price will be right (and if it's custom, you're almost totally screwed if the budget rules remain the same. It would be prohibitively expensive to have to account for fair market value of the labor involved). There's too many unknowns for me to be willing to plan my drivetrain around the expectation that these components can be purchased COTS.

There's a lot of thought and planning that needs to go into something like this. RC, I would encourage you to talk to Andy or Mark and they could fill you in on how much work it is. I'm just worried that your sponsor may think he's going to be doing a couple parts here and there and not really understand the magnitude of such an undertaking. He may not realize that he could be on the hook for 1,000 parts that teams will be expecting to show up at their door within a week from the time they place the order.

Just with the knowledge of the processes involved, you could tie up a large sized shop for most of the 6 weeks fabricating all the various sizes of gears and sprockets. More, depending on the machines they have.

I'm not saying you shouldn't do it, but I think you should step back and take a look at the big picture, or find someone who can help you do so. It would be a shame for teams to be relying on this venture, and have it fold mid season because it turned out to be way harder than expected.

Thanks Cory, I won't be the one doing it. He wanted feedback and this will help him make a decision. I am just relaying the messages from everyone here to him.

Thatz all Cory. I do understand the magnitude of this and it is up to him how he handles it. I will talk to Andy about this. Thanks for the Advice Cory.

[=Martin=Taylor=]

I believe the Poofs and AM (they sell 1 al gear) had their gears anodized and teflon-impregnated. I don't claim to know much about Materials Science, but I'd be wary of using aluminum gears. In my experience, rubbing aluminum on aluminum doesn't work too good.

Would I use al gears in a manipulator? Absolutely.

Wouldn't bother with sprockets. You can just attach an AM sprocket to a hub and make a good al sprocket, which requires no broaching.

[Tristan Lall]

I'm particularly interested in the possibilities for small ANSI B29.1 #25 and #35 sprockets, especially if they're offered with Ø0.5 in ANSI B17.1 keyed bores.

For the gears, it might be nice to have 7075-T6 drop-in replacements for some of the AndyMark Toughbox and Super Shifter gears (AISI 4140, 20 pitch, 14.5° pressure angle). Maybe AndyMark would even be interested in distributing those....

And versions of the ubiquitous 20 pitch, 14.5° pressure angle change gears would probably be popular among FIRST teams. Regarding other pitches and options, the more information you (or your supplier) can provide, the better.

Also, as a public service announcement, remember that per 2008 FRC rules, if parts are custom-made by a non-team source, you must account for the costs of materials and labour; if bought as COTS items, only the part cost matters. That's why I was interested in whether this would be a custom-order or catalogue business.

[colin340]

i like the idea of Sprockets they should wear much better than 6061

but at for the gears i think it would be hard to make them based on the great deal of different gears need

[JesseK]

Teams that do shoulder joints or other large rotational joints will probably be interested in a large diameter 72-tooth #25 flat sprocket. I usually see 3-4 of these gigantic sprockets at any given regional, and usually there's some intricate pattern drilled into them to reduce weight. For simplicity's sake, I'd rather just drill the holes to mount the sprocket rather than worrying about part strength after machining, which no one on our team knows how to calculate or simulate.

Other than that I'm very interested in 22-32 tooth flat #25 sprockets with a bore large enough for a 3/8" ID bearing. Also, 14-28 tooth hubbed #25 sprockets with a 1/2" bore, keyed @ 1/8" or not keyed at all. That's the thing -- if we order online there should be a little "key this hubbed sprocket!" box for a couple of bucks more. Many teams have no way to precision cut a keyway (our Arbor press squeezed its way out of the tooling budget this year in favor of more needed accessories for the mill/lathe ).

Rather than directly compete with AM, perhaps it would be better simply to offer products that AM doesn't carry at the moment?

[Nick E]

I don't honestly see the wieght savings(I know how light it is, I'm just not sure the cost of them justifies the savings). Also, will these be annodized? Or will they be left raw? I know the 7075 is a heck of a lot stronger(automag bodies) than 6061, but is apparently much harder to annodize. This could icrease your cost some.

[R.C.]

Originally Posted by Nick E

I don't honestly see the wieght savings(I know how light it is, I'm just not sure the cost of them justifies the savings). Also, will these be annodized? Or will they be left raw? I know the 7075 is a heck of a lot stronger(automag bodies) than 6061, but is apparently much harder to annodize. This could icrease your cost some.

It will be anodized if wanted, upon request. We have some plans to open a team 1323 store and we have been talking to first about it. Just keep an eye open =).

[Cory]

Originally Posted by Nick E

I don't honestly see the wieght savings(I know how light it is, I'm just not sure the cost of them justifies the savings). Also, will these be annodized? Or will they be left raw? I know the 7075 is a heck of a lot stronger(automag bodies) than 6061, but is apparently much harder to annodize. This could icrease your cost some.

Any shop that specializes in anodizing and other painting/coating processes can do 7075 as easily and well as they do 6061.

Originally Posted by rc_cola1323

It will be anodized if wanted, upon request. We have some plans to open a team 1323 store and we have been talking to first about it. Just keep an eye open =).

Keep in mind that per the 2008 rules to meet the FIRST provided definition of "Vendor" a business must be in no way affiliated with a FIRST team.

[Dick Linn]

If you need medium to large 7075 sprockets, these folks claim to make them to order:

http://www.rebelgears.com/sprockets/chainsizes.html

[Tristan Lall]

Originally Posted by rc_cola1323

It will be anodized if wanted, upon request. We have some plans to open a team 1323 store and we have been talking to first about it. Just keep an eye open =).

Like Cory said, be careful with the vendor requirements. I'd suggest having your supplier be the business of record here. You can always separately arrange for them to sponsor you with a cut of the profits on FIRST-related items (if that was the intended benefit of having a Team-1323-branded store).

And if your supplier chooses to sell to teams, it would be nice if you could make sure that they have a webpage with a gear and sprocket catalogue, including part schematics, material and surface treatment information and tolerances. Also, if you're planning to sell these during the 2009 season, teams will want to know what the lead time and shipping costs will be, in addition to the part costs—and they'd love to know these things as soon as possible (particularly before Christmas holidays begin).

And though I'm repeating my previous comments a little, I do want to stress that a catalogue would go a long way toward establishing these as COTS parts, as opposed to custom orders. (COTS parts aren't necessarily literally "off the shelf", or from stock; instead, they're effectively standard items with relatively short lead times. The distinction is useful, because teams must account for labour costs on the BOM for custom parts, but don't have to for COTS items.)

The faster you can arrange for this information to be posted, the quicker teams will be able to decide whether or not they're interested in doing business. For my part, I appreciate good information in order to make it easier to commit to using a new supplier for critical parts.