15 tooth + double sprockets
 

Does anyone know where I can find #35 double sprockets greater than 15 tooth? I've searched for a while on Google, but haven't been able to find them. Andymark only has 15 tooth ones max.

Thanks! :D

Re: 15 tooth + double sprockets
 

You can try mcmaster.com, they show a double strand sprocket up to 20 tooth. You may hex broach the sprockets and put them on a live axel. Use hex shaft and turn down the ends to fit your bearing. I'm sorry if you don't have the facility to do this. send me a message and I'll help you with it as I have the tools ready for your use. mrpalmere@verizon.net

Re: 15 tooth + double sprockets
 

Thanks all! I looked on McMaster and the only double sprockets they had weren't like the ones in the kit of parts, or at least didn't look like them. The one in the kit of parts is essentially the one we need, however we'd prefer a larger sprocket than what Andymark offers. Plus, a key broach is sorta what we're going for.

Re: 15 tooth + double sprockets
 

Double strand is not the same as double sprocket. Double strand is meant for 35-2 chain, unlike the AndyMark-type double sprocket, which is meant for two separate loops of 35-1 chain. I don't think you can use the former as a substitute for the latter, because the separation between sprockets is too tight.

Re: 15 tooth + double sprockets
 

Yeah. Sorry for not clarifying. I need to know where I can get a +15 tooth double sprocket, not a double strand. My bad for not being clear. :o

Re: 15 tooth + double sprockets
 

It's less a clarity issue than an availability issue. Most (probably almost all) "double sprockets" are made for double strand chain, so even I slipped up on that point from my initial Google search. Alas.

Back to the search engine!

Alternatively, make your own by bolting two sprockets together (actually, that sounds kind of fishy engineering to me...) or machine it.

Re: 15 tooth + double sprockets
 

We're not very good in machining sprockets, and the build season isn't a time to try it out for the first time. ;)

Re: 15 tooth + double sprockets
 

I do think double sprockets will be hard to find, especially if you want them in aluminum like the andymark ones.

Although a machined double sprocket would probably be inherently stronger, I don't see why bolting sprockets together would be "fishy engineering." If the bolts are properly sized, there's no reason for them to fail. Bolts are used to transfer rotation between two parts on dead axles all the time, so why not between two sprockets?

Alternatively, you could simply use two broached sprockets, mounted back-to-back on the same shaft.

Re: 15 tooth + double sprockets
 

It's a little more expensive, but you can use 2 AM sprockets & a hub, bolted together. For example, 22 tooth use 2 AM S35-22 & 1 AM0096

Edit: posts above while I was writing. I wouldn't call it "fishy engineering", multiple sprockets are bolted together often, for example, many 6 or 8 wd drivetrains have multiple sprockets bolted to wheels to power adjacent axles.

Re: 15 tooth + double sprockets
 

I just try to be wary of slapped-together, poorly thought-through, solutions, and that was very much a spur of the moment idea.

Re: 15 tooth + double sprockets
 

http://www.3dcontentcentral.net/3DCo...aspx?id=290003

you could assmble 2 of these together on the same shaft maybe?

Re: 15 tooth + double sprockets
 

You can't; it's not really a thing that's used often in industry in my experience.

Re: 15 tooth + double sprockets
 

Are you looking for something like this?

Re: 15 tooth + double sprockets
 

Bolting two sprockets together is popular and I have used it without any problems. Any pair of AM sprockets, properly sized bolts, and spacers (possibly the AM Delrin) should be fine. If you want something proven try these:

http://www.vexrobotics.com/products/...hdwr-dual.html

Re: 15 tooth + double sprockets
 

I think you may have solved all of my problems! Thanks!

Re: 15 tooth + double sprockets
 

I don't want to burst your bubble, but all that does is bolt two sprockets together ;)

Re: 15 tooth + double sprockets
 

aww.

Re: 15 tooth + double sprockets
 

I don't know if they offer 15T with that hub. That system does allow for a double sprocket (2x single strand). I know for a fact that Linn-Gear offers the ability to weld an A (hub-less) sprocket and a B (hubbed) sprocket together as well as what ever bore and broach needed. They are open 24/7 and have great turn around times since they not only support manufacturers but our local logging industry, or what's left of it.

Re: 15 tooth + double sprockets
 

Re: 15 tooth + double sprockets
 

I can't tell by the picture if these will work or not. They look like it, however it needs to resemble the one from Andymark and be a key bore. I can't find anything on the page saying so.

If it works, then my problems are solved! :D

Re: 15 tooth + double sprockets
 

http://www.vexrobotics.com/products/...hdwr-dual.html !!!!!!!!!!!!!!!!!!!!!!!!!!

EDIT: Fixed

Re: 15 tooth + double sprockets
 

Error 404: Page not found. :|

Re: 15 tooth + double sprockets
 

Found what you're looking for: http://www.vexrobotics.com/products/...hdwr-dual.html

Looks good, but how far apart are the sprockets spaced? They need to be the same space away from each other as the ones from AndyMark are.

Plus, it's for a CIMple box output shaft, so they'll need to fit there on the key bore and everything.

EDIT: I did the math (Haven't saved the world yet, build hasn't started), and found out that if I use smaller sprockets on the wheels, I can get the preferred speed. So since I also can't find any wheel-mountable sprockets smaller than 22 teeth, does anyone here know of any smaller sprockets that are also wheel-mountable? This should be easier to find then the double sprockets.

Re: 15 tooth + double sprockets
 

Well, saying you want a wheel mountable sprockets is like telling us you want an umbrella with a stick.

As you might have guessed, there are many variables about aforementioned wheel. But, using my excellent literary analysis skills, I'm going to assume you're going to be using AndyMark wheels.

Using 'small' sprockets on the AndyMark wheels can prove a bit challenging. First off, 'small' isn't very specific, but there are a couple of...regions of small.

So, from my knowledge of the Andy Mark Plaction Wheels, you can get away with a #35 chain sprocket of at least a 24 teeth without having to use the 1/4" spacers. If for some reason you need exactly 22 teeth, you're going to need to use the 1/4" space so the chain doesn't hit the wheel hub.

Any smaller than 22 teeth and you're looking at a live axle system. For this, I would recommend using the AndyMark Performance Wheels. From here, you can buy the sprockets which are hubbed with keys or hex from nearly anywhere and just slide them onto the axle.

- Sunny G.

Re: 15 tooth + double sprockets
 

I think he means wheel mounted as opposed to put on a live axle.

Re: 15 tooth + double sprockets
 

As to your original question, the term you want is a "double single sprocket" or "double simplex sprocket". Like these:

• http://www.ustsubaki.com/pdf/sprocke...ble_single.pdf
• http://www.jointway.com/catalog/F.pdf
• http://www.martinsprocket.com/2001/SecEa.pdf#E32
• http://www.gd-chain.com/double-simplex-sprocket.htm
• http://www.duramax.cn/Images/1class/...eSimplex/1.jpg

Unfortunately, most often they seem to be typically available for ANSI #40 roller chain and larger, or British 06 chain (which I doubt would match). (Some are in China, so there's the distribution problem as well.)

There's always custom fabrication—these guys say they can make it—better still, find a sponsor to make it.

(In case you're wondering, these double single sprockets are used in some conveyor systems.)

Re: 15 tooth + double sprockets
 

The wheels (the mounting part, not the tread surface) can also be turned down to a diameter that will allow the chain walls to fit. But you're still limited to 22 teeth because of the size of the bolt circle AndyMark uses. To wheel-mount a smaller sprocket you'd have to make a new bolt circle on the wheel and sprocket somehow.

Re: 15 tooth + double sprockets
 

Ok, here's the clarification:
For my drive, there is a 15-tooth double sprocket on the CIMple box output shaft. That will be connect by #35 chain to the wheels via a 22 tooth sprocket. However, to achieve the speed desired, I will either need to increase the size of the double sprocket, or decrease the size of the sprocket attached to the wheel.

Again, thanks to all of those who have answered so far, I really appreciate it, since I'm mechanically dumb (so far). ;)

Re: 15 tooth + double sprockets
 

Can you just reduce the max speed in code? Or does that cause too much of a loss in torque?

Re: 15 tooth + double sprockets
 

We can, but we're trying to increase the max speed. It's currently at 10.97 fps, however we want to see if we can go higher than that.

ALSO, I have noticed some people saying that by using the 22 tooth sprocket from Andymark, the chain won't fit. Is that because of the wheel, or something else? I'll be using 4" plaction wheels.

Re: 15 tooth + double sprockets
 

On the output shaft for the transmission I fail to see the issue with simply stacking two hubbed sprockets, this may require you to face them (to get the proper spacing) but this is what AM does in the AM-Shifters.

Look at the output sprockets as shown on the drawing below:
http://files.andymark.com/amshifter-asm.pdf

McMaster has a large selection of standard #35 sprockets, however you will need to broach the keyway/hex yourself.

Re: 15 tooth + double sprockets
 

Oh, you're right, I read that backwards. durpty durp.

The 22-tooth sprocket "doesn't fit" any of the plaction wheels because the plaction wheels have a built-in hub (same size and design, no matter the wheel size) that offsets the sprocket from the wheel. The diameter of that hub is too large when you use a 22-tooth sprocket because the chain walls rest on the hub instead of the rollers resting in the troughs between teeth, which can lead to jumped chain and inconsistent driving. AndyMark sells spacers and hubs with a diameter small enough for the 22-tooth sprocket, but there is also enough material in the wheel for you to turn down the built-in hub to a usable diameter with your handy-dandy lathe.

Re: 15 tooth + double sprockets
 

Justin beat me to the reply, but I totally agree with him.

I am failing to see why a double sprocket is necessary.

-Brando

Re: 15 tooth + double sprockets
 

what is the purpose of bolting together two sprockets ?

if you need two sprockets, then put two singles on the shaft.

the main advantage of the AM part is it reduces a ton of weight relative to the older method of installing two steel single sprockets.

Re: 15 tooth + double sprockets
 

Long ago in the dark days of pre kitbot FIRST we would buy ANSI triple roller chain sprockets and turn off the middle set of teeth on the lathe to solve this issue. Not sure if this is helpful but I know we still have a buck of these kicking around the shop.

Re: 15 tooth + double sprockets
 

I guess we'll have to try that. Thanks! I've no experience in this, however our mechanical team should know.