Cogs for double-pitch roller chain

When I saw the pictures on your last post, I thought I would ask this question -

Is there a rule of thumb for the cog diameter when using a standard-pitch cog for double-pitch chain?

A couple weeks ago, I was running a spreader and the original cog on the pto shaft (NI spreader, #60 double-pitch chain) let loose.

The proprietor at one of the bearing shops we stopped at mentioned that a double-pitch chain would tend to "climb" on a cog (sproket?) with an even number of teeth, if the cog is above (below?) a certain diameter.

So we dutifully kept searching until we found a cog with an odd number of teeth (31 it turned out).

Have you heard anything like this before? My neighbor has dealt with this gentleman for ~15 years, and he has a good reputation.

Thanks for any (and all) input.

Nathaniel

Walt,
This strange idea came from the fellow at the local Kaman Bearing house. He is believable and reliable. Being a young sprout, I've found its often VERY worthwhile to listen to my elders, who have "been around the block".

Gerald,
I can see the logic of "wear every tooth", makes sense to me. Of course, we could always shift the chain by one tooth and wear a different part of the even-tooth sprocket. (Like we'd remember to move the chain!)

Rod,
In my case, the chain and the other sprocket appear in fine shape. We purposely went to a standard pitch sprocket for three reasons - price, availability, and future flexibility. The double-pitch chain rides in the standard pitch sprocket just fine, in the future (if the other sprocket fails) we will upgrade to standard chain.

Don,
Thanks for clarifying the terminology. I just knew better than to call it a pulley or shiv. (grin).

Nathaniel

Nothing wrong with respecting your elders. That said, I know an older fellow around here that's worked around equipment all his life both repairing and designing stuff. Very very smart man, and I've got a lot of respect for him too... but he does make mistakes from time to time, the same as I do. We got into a discussion about eccentric locking collars one day, and which direction they're to be locked. He said against the direction fo rotation. I said in the direction of rotation (I knew because I'd read a chart on that very subject at the bearing supplier days before.....) Came up because he locked a bearing against, and the collar went AWOL. So... we don't all know everything, even when we're old.

Rod

Nathaniel

I can see why a guy would want to use an odd numbered sprocket if mix'n and match'n for wear purposes, but it woun' affect the shain wanting to climb. That's just a stretched chain that wears on the outside of the tooth instead of the root diameter where it's supposed to ride.

In the even a chain is stretched and is allowed to wear the sprockets up on top, you gotta replace the whole works because it wears the sprockets so that a new chain would ride up on them, and the new chain will soon be stretched just like the old one. If the sprocket is worn more on the bottom, you can ussually get away with just replacing the chain once, then chances are it'll be too far gone the next time. Since I've worked there, I've replaced many a sprockets on our farm with new ones, especially the AGCO equipment (Mainly New Idea) with new ones form work because we made them for AGCO, for both new machines in production and for the parts counter support on older ones.

I no longer work there, but I'm still freinds with the owners and stop in now & then for a new sprocket or 2.

Rod

I see in my Shoup catalog that it depends on the source and the size whether double pitch chain is cheaper than single per foot. Its true sometimes and in manufacturing quantities is more likely to be true.

Gerald J.

Gerald J.

The new one will be regular 60 with 30 teeth and #60 chain.

Twice as many cogs to pull on in my mind.

Gary

That would make sense to me.

I could see problems from using old chain on new cogs...

We couldn't figure how the number of teeth (as long as we were close to the original) would make a difference. We put the odd-tooth cog on and it worked fine, even with the old chain.

Nathaniel

Gary