Chain Sprockets

[gabby]

Hi there all,
Yup Chain Sprockets, Does anyone know if there are formula's etc. to enable me to manufacture a set of sprockets to suit an old model that I am resurrecting.
I need to keep it with the chain driven timing to make it look right.
Cheers
Graham

 

[b.lindsey]

Graham, If you have access to a copy of machinery's handbook there is a lot of information there on chain sprockets, including formulae, based on the size of the chain, pitch, etc.

Bill

 

[gbritnell]

Here's a simplified version.
http://www.gizmology.net/sprockets.htm
gbritnell

 

[gabby]

Hi there Bill and gbritnell,
Sorry Bill but I don't have a copy of the handbook, that is on the wish list at the moment.
The gizmology layout looks easy to follow, but to be sure I will make a couple out of scrap to see if I can get the theory right before I waste some Brass or similar.
Many thanx gentlemen.
Graham

 

[tel]

That's always a good approach Graham, know where you are goig before you set out.

 

[popnrattle]

Hello, I have uploaded a video to youtube that you could try. I use autocad '04 in this video and hopefully it is clear enough for you to understand. Then, I import to the cam software. Also included is the chain size chart with standard pitches and corresponding roller sizes. Let me know if you got any questions. Good luck. Later, Rick.

[ame]http://www.youtube.com/watch?v=N8bcoL-4jwg[/ame]

 

[kvom]

The gear template generator software from woodgears.ca will generate sprockets as well as gears. If you post up the dimensions of the chain I'd be happy to plug them in and send you a drawing.

 

[gabby]

;D Hi All,
Many thanks for the replies, I have had a look at the various leads to making chain sprockets and have found that the link from gbritnell seems to have a flaw in the calcs, I got every thing worked out up to the point of "cot", that bit I can't seem to get my head around.
Please tell me if I missed something as my school boy math days were so long ago lol.
The wooden sprocket calc is nice and gives me a very easy way to design a sprocket and at some point in the future I will probably buy the program as it is useful for gears as well.
Also I don't have any form of automation in the shed as I run my lathe and mill on manual mainly because to many buttons will only confuse the hell out of me (ha ha is that a logical answer ?).
However this problem I have with the above calc with the "cot" in it has me itching to find out what it stands for, I even tried "cos" in case it was a miss print then I thought to myself, hmmm other people have used this process, there must be a simple answer that I have missed.
Please tell me because those sorts of things spook me until I get a logical answer and I can then complete the design of the sprocket.
Also please don't get me wrong, I'm not complaining, whinging or any other form of negative thinking, I just have a burning need to know. ??? ??? ??? :

 

[gabby]

Also I just have to get a copy of Machinery Handbook.
Many many thanx to all
Graham

 

[kvom]

In math, COT stands for cotangent.

 

[Mainer]

There do exist form cutters for chain sprockets similar to those available for cutting gear teeth. Presumably they come in sets of 8 or 15. I know they exist because I have a couple of them that were part of a box lot or something I picked up years ago. They are far too large to be useful, but of course I haven't gotten rid of them.

I suspect, however, that even if you could find one in the size you needed, it would be prohibitively expensive.
I've never seen any for sale.

 

[n4zou]

What size sprockets and chain do you require? Have you thought of using bicycle sprockets and chain? I have taken apart a new Cassette (Sprocket cluster attached to the rear wheel hub) and used two of the sprockets for cam timing.
Here is a perfect example:
Nashbar 8-speed Cassettes
http://www.nashbar.com/bikes/Product_10053_10052_174999_-1_203103_10000_202344

SIZE 2 has 12 and 24 tooth sprockets that would work fine for a chain driven cam timing system.

If you only need 2 sprockets with the same tooth count for a steam engine this link has them in several different toot counts.
https://www.jrbicycles.com/storefront/index.php?act=viewProd&productId=660

 

[gabby]

Hi All,
Firstly many thanx for the great communications, I am trying my best to not use bicycle sprockets as I feel the chain would look way to chunky for the end look of the engine.
What I am hoping to use is 1/4" centre chain at a 2 to 1 ratio, the driving sprocket that I was hoping to use is 18 teeth and 1 1/2" diameter, but looking at it I feel that I may require a smaller driver (maybe 14 teeth) as the size of the o/all of the bigger sprocket may almost encroach on the teeth of the smaller one.
So I may be making both gears, I had also had thoughts of making a cutter (not unlike a gear cutter) to cut the teeth, I can only assume that this process has been done before.
One confession I have to make at this stage is that my next gear/ sprocket will be my first one so please excuse the liberal lashings of ignorance.
Cheers
Graham

 

[Mainer]

http://www.wmberg.com has 1/4" pitch roller chain and sprockets, although I think you should make at least one sprocket just for the bragging rights.

 

[narrowgauger]

for ultra small pitch roller chain go to [email protected].

best prices and wide range of sprockets & chain ex stock.

Laurence will happily sell you one inch or any length you need. PSME may also be contacted by phone (508) 478 3148.

No connection except as a very happy professional customer over many years.

have fun
Bernard

 

[ruzzie]

Here is a sprocket a colleague made for his “electric bike project”
It took 4 or 5 setup on the cnc because it didn’t have enough travel to do it all in one setup.