Feasibility of using chain & sprockets as gears?

[strantor]

Scrap bin find: got several large 24B sprockets and a small scrap of chain. I don't have enough chain to do anything useful with this, and the chain is very expensive. I'm not planning on buying more. So the thought occurred to me to wrap the chain around one sprocket and have another sprocket mesh with it, like a gear. But the problem is that the teeth of the two sprockets hit each other.



In the above picture you see what I mean. The large sprocket with the chain around it would have the 5 free links cut off and then be attached to itself for a continuous loop around the large sprocket and the smaller sprocket at the bottom would mesh with it. Except the tips of the sprocket teeth touch before meshing can occur.

But what if I cut the tips off of all the teeth off of the large sprocket and then welded it in place, so that the smaller sprocket could mesh?

Would this work?

If so, what are the implications? In my mind, there are positives and negatives; please peer review my ideas:

(I think it will work with some caveats)

1. Positive. The horsepower capacity charts in chain drive datasheets drops off dramatically as RPM increases above a certain threshold. This is (I think) due to the chain's ability to flex at high speed without flapping. Since it won't be flexing, it should be capable of much higher speed. Closer to a gear set's speed/power curve at high speed.
2. Negative. The limiting factor of applied torque in typical chain drive applications is based on tensile strength of the chain (I think) which is much lower than the sum of the strength of the number (typically high number) of individual teeth engaged, so tooth strength is disregarded and the teeth are probably not hardened for added strength like gear teeth are. Since now only 1 or 2 teeth will be engaged at a time, the focus shifts to shear strength of the chain pins and the sprocket teeth, to which probably very little attention was ever paid in the factory. This is a bit of a wild card. I won't know how much torque I can put on it until I find it empirically, at which point I don't have any replacement parts. But I can't see the pins or teeth shearing without astronomical torque applied.

 

[T Bredehoft]

Note to advisors, Rmove the first sentence is if seems derogatory.

As a toolmaker, to me it seems a farmer's solution to a mechanic's problem. It might work, but I wouldn't count on any high speed success. Wear would be a limiting problem, the faster it goes the faster the teeth would wear away.

 

[strantor]

Note to advisors, Rmove the first sentence is if seems derogatory.

As a toolmaker, to me it seems a farmer's solution to a mechanic's problem. It might work, but I wouldn't count on any high speed success. Wear would be a limiting problem, the faster it goes the faster the teeth would wear away.

Note to all: I'm not offended. I don't consider it derogatory. Thank you for your input.

 

[Jubil]

Scrap bin find: got several large 24B sprockets and a small scrap of chain. I don't have enough chain to do anything useful with this, and the chain is very expensive. I'm not planning on buying more. So the thought occurred to me to wrap the chain around one sprocket and have another sprocket mesh with it, like a gear. But the problem is that the teeth of the two sprockets hit each other.

View attachment 293559

In the above picture you see what I mean. The large sprocket with the chain around it would have the 5 free links cut off and then be attached to itself for a continuous loop around the large sprocket and the smaller sprocket at the bottom would mesh with it. Except the tips of the sprocket teeth touch before meshing can occur.

But what if I cut the tips off of all the teeth off of the large sprocket and then welded it in place, so that the smaller sprocket could mesh?

Would this work?

If so, what are the implications? In my mind, there are positives and negatives; please peer review my ideas:

(I think it will work with some caveats)

1. Positive. The horsepower capacity charts in chain drive datasheets drops off dramatically as RPM increases above a certain threshold. This is (I think) due to the chain's ability to flex at high speed without flapping. Since it won't be flexing, it should be capable of much higher speed. Closer to a gear set's speed/power curve at high speed.
2. Negative. The limiting factor of applied torque in typical chain drive applications is based on tensile strength of the chain (I think) which is much lower than the sum of the strength of the number (typically high number) of individual teeth engaged, so tooth strength is disregarded and the teeth are probably not hardened for added strength like gear teeth are. Since now only 1 or 2 teeth will be engaged at a time, the focus shifts to shear strength of the chain pins and the sprocket teeth, to which probably very little attention was ever paid in the factory. This is a bit of a wild card. I won't know how much torque I can put on it until I find it empirically, at which point I don't have any replacement parts. But I can't see the pins or teeth shearing without astronomical torque applied.

If it is possible, rotation would be reversed, but maybe it doesn't matter.
Chuck

 

[Ulma Doctor]

i love a challenge, maybe more than the next guy,
but,
i'm having a hard time envisioning how you would have the sprocket teeth from 2 sprockets mesh with the chain and provide positive engagement.
if you were to remove surface mass of the individual teeth, wear would surely take the remaining tooth mass rapidly.
backlash would have to be finely adjustable as well. conceivably there would be need for constant adjustment as well.

could it work for a low tech drive? sure it could.
are there better drive systems? yes

another possibility is to remove the teeth and machine them into 3V pulleys, for belt drive
or otherwise modify them into drums for use with belts

 

[matthewsx]

Without a proposed application it's very difficult to say.

But, probably not.

 

[Superburban]

If you are intent on using the old parts, I would cut all the teeth (or about 95% of the tooth profile) off the big one, and then weld the chain on to it. Now you have a female sprocket, that will mesh better with the other sprocket. Never heard of it being done, would be interesting to see how it works. I would not expect any great lifespan, as the chain rollers will not be able to rotate, and will likely wear fairly fast.

 

[Bi11Hudson]

As an Ex-biker, electrician, pretty good carpenter, and jack leg machinist and mechanic, I will concur with your idea. But, only concur, not support it. I agree with a response above that you should turn down the one sprocket so the other has some clearance. And I truly believe you can ignore the stress on the chain as it will be rigidly attached to the driving sprocket. Simply as a "filler" for the empty space. The limiting factor will be the strenth of the non hardened sprockets. On a bike, when you replace the chain, you should also take a long, hard look at the sprockets too. Chain stretch will ruin a sprocket as quick as it will the chain.

I would quote Lazarus Long here that "You should always listen to the experts. They will tell you what cannot be done, and why. Once you have heard them, go on out and do it." If we all listened to expert opinion, we would still be throwing spears to put supper on the dinner rock. Just remember, "there ain't no free lunch." If you do something and get hurt, it was because you went against expert opinion. If it does work and makes you a rich man, be sure to flaunt it in the faces of the "ex spurts", the has been wannabes. Just remember that they can, and often do, fight back when someone upsets the status quo.

Now, the con side; It won't be as strong as a gear set. Nor can it run as fast. But for a shade tree fix, it can work wonders until you can do better. Or, give up the idea in favor of something more interesting, more important, or better paying.

To digress (sorta) back to 1974 or so, when I rode a MC from New Orleans (NOLA) to Salt Lake City with less than 50 bux in my pocket, some of the things I had to do to keep the bike running are beyond a simple explanation, needing a small book to explain. But the fixes got me to a town large enough to have the facilities I needed. And a little work to pay for the parts that couldn't be cobbled together.

Bill Hudson
WWW.HUDSONTELCOM.COM​

 

[stupoty]

Scrap bin find: got several large 24B sprockets and a small scrap of chain. I don't have enough chain to do anything useful with this, and the chain is very expensive. I'm not planning on buying more. So the thought occurred to me to wrap the chain around one sprocket and have another sprocket mesh with it, like a gear. But the problem is that the teeth of the two sprockets hit each other.

View attachment 293559

In the above picture you see what I mean. The large sprocket with the chain around it would have the 5 free links cut off and then be attached to itself for a continuous loop around the large sprocket and the smaller sprocket at the bottom would mesh with it. Except the tips of the sprocket teeth touch before meshing can occur.

But what if I cut the tips off of all the teeth off of the large sprocket and then welded it in place, so that the smaller sprocket could mesh?

Would this work?

If so, what are the implications? In my mind, there are positives and negatives; please peer review my ideas:

(I think it will work with some caveats)

1. Positive. The horsepower capacity charts in chain drive datasheets drops off dramatically as RPM increases above a certain threshold. This is (I think) due to the chain's ability to flex at high speed without flapping. Since it won't be flexing, it should be capable of much higher speed. Closer to a gear set's speed/power curve at high speed.
2. Negative. The limiting factor of applied torque in typical chain drive applications is based on tensile strength of the chain (I think) which is much lower than the sum of the strength of the number (typically high number) of individual teeth engaged, so tooth strength is disregarded and the teeth are probably not hardened for added strength like gear teeth are. Since now only 1 or 2 teeth will be engaged at a time, the focus shifts to shear strength of the chain pins and the sprocket teeth, to which probably very little attention was ever paid in the factory. This is a bit of a wild card. I won't know how much torque I can put on it until I find it empirically, at which point I don't have any replacement parts. But I can't see the pins or teeth shearing without astronomical torque applied.

Sprockets like that look kinda expensive ?

Kettenrad 24B-1, Z=30, vorgeb.

Kettenrad 24B-1, Zähne=30, vorgebohrt Die Maße des Kettenrades entnehmen Sie bitte den technischen Details . Sparen Sie…

www.kettentechnik-shop.de

30 tooth nearly 200 euro bucks

15 tooth nearly 60 euro bucks

They look new old stock with some rust on them , maybe wire wheel and ebay them to purchase material or specific gears for your project.

(If you have already cut them up , their like 10 a penny, no one want's them , yeah sounds like a good idea )

Stu

 

[epanzella]

Assuming the obvious problems of meshing can be solved, I think the biggest limitation is that the chain is curved the wrong way for one of the sprockets limiting the drive to one tooth and one link of chain. Chain drives are designed to transfer power thru about half the teeth on the sprocket.