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Commander_Chaos
06-05-2013, 07:59 PM
I'm trying my hand at making a set of roller starters for my race bike. I found these industrial rollers with sprockets already welded to them, but I can't figure out what size chain they take. The rollers have metric bearings, so maybe the chain is metric, too?
http://nort_comm.tripod.com/hobbies/rollers/bottom_of_teeth.jpg
http://nort_comm.tripod.com/hobbies/rollers/topofteeth.jpg
http://nort_comm.tripod.com/hobbies/rollers/width.jpg

kf2qd
06-05-2013, 08:03 PM
What size pin fits the sprocket and what is the center distance between pins. Then do a search using Roller Chain Specs. There are several sources of charts showing almost any chain you could every want.

Many bearings are metric, that doesn't tell where something came from.

Commander_Chaos
06-05-2013, 08:17 PM
The metric thing was just a guess based on who might have built the original machine and what system they preferred.

I don't have a piece of chain that fits it so I can't measure the pins. I'm trying to measure the sprockets against the charts on McMaster Carr. Are my pix clear enough to read the measurements?

darryl
06-05-2013, 08:37 PM
You could machine up a pair of test diameters to a size that nests nicely into the gullets. Then measure the distance between the centers of them. That will only take a couple of minutes, and it will give you the diameter the rollers should be and the link centers length. Width- I'd measure it then make sure the chain you get is a little wider. Chances are the right chain size will emerge.

BigMike782
06-05-2013, 09:30 PM
Stop at the Farm supply(Rural King,Tractor Supply etc) and try out different sizes.

lane
06-05-2013, 09:53 PM
From the pictures I would say # 40 chain. At least my first try. Their is an odd ball #41 chain but do not think it would be that . And 35 is a lot smaller.

Willy
06-05-2013, 10:05 PM
Kind of looks like 428.
I/2" pitch with 5/16" wide rollers.
Have a look at this chart from Diamond.
http://www.dansmc.com/diamondchainspecs2.jpg

Shuswap Pat
06-05-2013, 11:58 PM
Take your sprockets to farm supply (as mentioned) or Industrial supplier, they can match it up. If you take the chain number (except 35 & 41) and divide by 80 - it is the chain pitch - 40/80 = 1/2" pitch : 80/80 = 1" pitch. 35 & 41 are a litle different 35 = 3/8 ptch, and 41 is 1/2" but narrower.

Metric chain is not realy metric but a bastardized imperial to a BS (British Standard). Some Imperial sprockets will run Metric chain, some not.

Patrick

EVguru
06-06-2013, 06:31 AM
Looks like 0.625" or 5/8" pitch to me.

ANSI and BSI chains differ in inside width and sometimes roller diameter for a given pitch.

Norman Bain
06-07-2013, 06:47 PM
Hi,

There are two main standards. British Standard Roller Chain and American Standard Roller Chain. My findings are there is not a Metric standard (yet anyways in common use) as such; just that the dimensions of the two standards can be "converted" from Imperial to Metric.

These two links cover most of the sizes for both standards; but are missing the "magical gotcha" for #40 vs (the smaller) #41.
http://www.transeals.com/transmission/chain_sprockets.html
http://www.transeals.com/catalogues/downloads/Transeals_Chain_&_Sprocket_Guide-Metric.pdf

Here is link that contains #41 and #40 in size order:
http://www.gmtel.net/web/drittmer/Technical/mechanical/Roller%20Chains.pdf

wierdscience
06-07-2013, 10:49 PM
ANSI #40,I've worked with a few miles of it.

Commander_Chaos
06-10-2013, 08:37 PM
You could machine up a pair of test diameters to a size that nests nicely into the gullets. Then measure the distance between the centers of them. That will only take a couple of minutes, and it will give you the diameter the rollers should be and the link centers length. Width- I'd measure it then make sure the chain you get is a little wider. Chances are the right chain size will emerge.

Sorry for the slow thank-you. Since I'm far too lazy to fire up the lathe, I laid two 5/16" bolts between the teeth (they fit perfectly) and measured outside to outside. Then I subtracted the diameter of one of the bolts. It came out to exactly 1/2". Ordered the chain and it was just right. Thanks!