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A cheeky/optimistic request - 7/8 20 tpi die?

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Symon13/09/2017 15:36:03
18 forum posts

This is a bit cheeky considering none of you know me yet...but...I need a 7/8" 20tpi die (BSB?) to repair the thread on a shaft of my mill restoration. Tracy Tools have the taps and dies but I can't really afford to buy them for just one quick job.

Would any of you guys have one I could borrow? embarrassedObviously I'd cover the postage costs (both ways) and love you forever heart

Sorry about the sheer nerve...but I'm a wee bit desperate.

Chris Evans 613/09/2017 16:25:06
929 forum posts

I will look in my workshop tomorrow, I do have a selection of odd ball stuff. Will PM if I find one.

Symon13/09/2017 16:28:08
18 forum posts

That's greatly appreciated, Chris beer

not done it yet13/09/2017 16:39:15
998 forum posts
3 photos

Do you really need a die or would a thread chaser be sufficient? A location might help, too. There might be someone local.

John Rudd13/09/2017 16:45:48
927 forum posts
53 photos
Posted by not done it yet on 13/09/2017 16:39:15:

Do you really need a die or would a thread chaser be sufficient? A location might help, too. There might be someone local.

His intro thread gives his location as Newcastle/Durham......oop north then....

Symon13/09/2017 16:47:37
18 forum posts

Ordinarily a thread chaser would probably do. But there's a part on the thread where an old pin is and that's stuck tight. So it'll need cut through. Also it's on the machine already which means no more bashing to get the pin out.

I'm in the North East between Durham and Newcastle.

Symon13/09/2017 17:04:23
18 forum posts

OP should be read BSC (British Standard Cycle).

David Standing 113/09/2017 18:33:39
442 forum posts
24 photos
Posted by Symon on 13/09/2017 17:04:23:

OP should be read BSC (British Standard Cycle).

Are you sure? I work on old cycles with BSC threads a lot, and 7/8" should be 24 tpi.

7/8 x 20 is however a UNEF size.

 

 

 

 

 

Edited By David Standing 1 on 13/09/2017 18:36:47

Clive Brown 113/09/2017 18:46:37
44 forum posts
4 photos

Tracey Tools refer to 7/8" x 20 as cycle thread, presumably where the OP is coming from.

if the pin area is the only problem, I wonder whether a small triangular file could be used to dress out the remains of the pin. The thread angle seems likely to be 60 deg.

Symon13/09/2017 18:55:21
18 forum posts

Yeh, TT calls it BSC: **LINK**

The threads measure 20tpi on my cheapo gauge, which I don't really trust...but it is.

The threads are just rounded a bit, not crossed, and I'll likely flatten the pin area to accept a grub screw instead of the original pin.

Symon13/09/2017 19:00:06
18 forum posts

Would it not be weird to have a unf/unef thread on a late 50s UK machine which uses Whitworth for the most part?

David Standing 113/09/2017 19:02:08
442 forum posts
24 photos
Posted by Clive Brown 1 on 13/09/2017 18:46:37:

Tracey Tools refer to 7/8" x 20 as cycle thread, presumably where the OP is coming from.

if the pin area is the only problem, I wonder whether a small triangular file could be used to dress out the remains of the pin. The thread angle seems likely to be 60 deg.

Yes, that's odd - Tracy Tools show two BSC pitches, 20 tpi and 26 tpi. All the cycles I have worked on are 26 tpi, 20 tpi is a new one on me!

David Standing 113/09/2017 19:03:26
442 forum posts
24 photos
Posted by Symon on 13/09/2017 19:00:06:

Would it not be weird to have a unf/unef thread on a late 50s UK machine which uses Whitworth for the most part?

If it is a British machine, yes! smiley

Symon13/09/2017 19:26:10
18 forum posts

Exactly. This thing has some weird threads, though. The pipework uses 26 tpi BSC which I had a friend tap an oil part as like now...I really didn't want to buy a use once part laugh. BSP was well in use at the time of manufacture, and it even uses BSP in places! Ha!

John Stevenson13/09/2017 19:27:39
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Moderator
5068 forum posts
3 photos
Posted by David Standing 1 on 13/09/2017 19:03:26:
Posted by Symon on 13/09/2017 19:00:06:

Would it not be weird to have a unf/unef thread on a late 50s UK machine which uses Whitworth for the most part?

If it is a British machine, yes! smiley

.

Once you get above a certain size you get an alternative of 20 from the normal 26. Pedal threads have always been 9/16" x 20 RH and LH

Chances are that I do have one, I have a full set up to 1" in RH and LH threads but I can't check as I'm off work for a while.

Can you use a thread file or at worst a small triangular file

Symon13/09/2017 19:27:44
18 forum posts

Still, it's looking beautiful, so can't be mad with it.

Symon13/09/2017 19:29:35
18 forum posts

No thread file atm. But I could always borrow one. Would rather clean it up with a die.

JohnF14/09/2017 09:40:11
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511 forum posts
26 photos

Symon see your messages

Symon14/09/2017 10:12:31
18 forum posts

yes

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