What is this chain?
 

Was given a box of older parts. Among them was this chain. Is this inch pitch? There were no other drive train parts in the box so I can’t test it. And despite my age, inch pitch was no longer in use when I started ridding. Plates are stamped BD USA.


https://cimg2.ibsrv.net/gimg/bikefor...7b172d7b2.jpeg
https://cimg3.ibsrv.net/gimg/bikefor...49c457e56.jpeg
https://cimg4.ibsrv.net/gimg/bikefor...1ba8b333d.jpeg

Skip tooth chain, similar one on ebay.
https://www.ebay.com/itm/38699244014...CABEgLfV_D_BwE

Yeah, inch-pitch. Looks low-miles, maybe even just shop-grime on a new chain? Some collector/restorer will probably pay decent money for it. Do you have a full bike's worth?
You can check for wear by measuring the full length, hanging from a nail at one end so gravity straightens it out. You don't need the length per se, but how far the last pin is past the nearest inch-mark. If all the pins fall exactly on inch-marks, then the chain is new or very low miles. A worn-out chain is something like 1/8" longer per foot, though you can still ride them like that.

For some reason that I don't understand, the cool trackies used to prefer block chain (ha ha the original block chain, before bitcoin!), and yours is not block chain. I see a couple block chains on ebay at the moment for $400 each! Personally I would rather have roller chain (like yours), and roller chain is the right stuff for any bike with inch pitch that's not a Match Sprint track bike. Prices not as crazy as for block chain.

Since I sold my '33 Excelsior, I have no bikes with inch pitch, so I'm not in the market. Check out The CABE, where there are more American heavyweight fans, though I'm sure we have a few here too.

I understand it was one of those folklore fads. Remember in the 1980s when we said a used steel frame was whipped (or whooped)? I'm sure we can think of all these fads that everyone understood. On example was the crank that was swaged to the spider. :)

Wide handlebars are best, no, narrow handlebars are best. Long cranks, no, short cranks. High pressure, no, low pressure.

so in inches, how low is a full bikes worth of chain? Counting links doesn’t seem like the way to go, given different link sizes

This is not exact but will get you in the ballpark:
Take the chainstay length of the frame and double it, example 17" x 2 is 34"
Take the teeth in the chainring and divide by two, example 26/2 = 13
Take the teeth in the rear sprocket and divide by two, example 10/2 = 5
Add those numbers, example 34 + 13 + 5 = 52". The real length will be slightly more than that. (The formula is exact when the F & R sprockets are the same size, which is almost never the case. Different sizes F&R requires a longer chain.)

Baldwin Duckworth branded inch pitch chain. They were sold with bikes new or in the cardboard box as aftermarket/repair parts. They're not especially rare or extremely valuable, but they do have some value if in good shape. The chain below sold for $90 in 2022. A two-tone Diamond chain in similar condition is more valuable and desirable for collectors of vintage American bikes. But the Baldwin Duckworth is still a good chain.

https://thecabe.com/forum/attachment...-jpeg.1636650/

Thanks for the ID. Springfield, Mass apparently was home to basketball AND bicycle chains.