Uniglide thread pitch?

[Simplex]

I haven't got a UG hub to try a BB lockring on but it certainly works the other way.

 

[one-eyed_jim]

I haven't got a UG hub to try a BB lockring on but it certainly works the other way.

Well, okay, you can force it on. But look at the squared off profile of the thread on the bottom bracket cup: either it was damaged before you started, or you damaged it while forcing the sprocket on.

I've got a Shimano BSC bottom bracket cup in good condition, with its original lockring, and three Uniglide sprockets, two of them NOS. The lockring threads on smoothly with just a tiny amount of play. None of the Uniglide sporckets will thread on more than half a turn before jamming.

I'll put some pictures up later.

 

[Woz]

I've used a standard BSA BB lock-ring on an old Shimano M730 rear 7 speed UG free hub for SS applications. Works a treat ;-)

 

[Simplex]

IMHO both threads are the same. I screwed the sprocket onto the BB cup by hand and it was a good fit.

 

[one-eyed_jim]

Well, I've found the thread details in my notes. Unfortunately I didn't note the source, but here's what I have:

Dura Ace: BC 32mm x 24tpi
600: BC 34.6mm x 24tpi

So that's about 0.2mm smaller in diameter than a BSC track sprocket thread. In some cases tolerances may allow it to work, but I've been trying my three Uniglide sprockets on every BSC track hub and BSC bottom bracket cup I have, and they're not going on without violence.

Here's a note from rec.bicycles.tech:

https://groups.google.com/group/rec.bic ... m+uniglide

I'll upload some pictures in the morning.

 

[foz]

Thanks for that Jim! only 0.2mm... you'd think they could have made it the same, but I guess the total diameter of the freehub body might not allow it.
I might be tempted to try it, as I only want to know if I can use a BB lockring to hold some spacers and a sprocket on a uniglide body, to make a singlespeed. The lockring only needs to hold the other bits on, it's not like it will be taking any torque.
Using a UG sprocket as a fixed sprocket on a screw-on hub is another matter though, and I won't be trying that in a hurry!

 

[Simplex]

Well, the sprocket went easily onto a Shimano DA hub and a chinese BB but got stuck after about two turns onto a good ol' Super Record. :roll:

 

[one-eyed_jim]

Well, for what it's worth, here a few of my photos.

First, here's the BSC cup with its lockring. The ring threads on easily, and spins all the way down:

http://www.flickr.com/photos/24213822@N ... otostream/

Now a SunTour BSC track sprocket. As expected, just like the lockring, it threads on easily and spins all the way down:

http://www.flickr.com/photos/24213822@N ... otostream/

Now a NOS 15t Uniglide sprocket. It doesn't start easily, and jams up after about half a turn. I could use tools to force it, but it's not going further by hand:

http://www.flickr.com/photos/24213822@N ... otostream/

Finally a NOS 13t Uniglide sprocket. Same result: it's jammed solid after half a turn:

http://www.flickr.com/photos/24213822@N ... otostream/

Similar results using a Campag Record track hub, a Dura Ace 7600 track hub, and various TA and Shimano bottom bracket cups. I could certainly use force to get the Uniglide sprockets onto the alloy components, but they'd be cutting new thread as they went.

So it seems tolerances may make it workable in some cases, but the Uniglide thread seems reliably tighter than BSC.