Hitchcocks Forum

as it part TC/PZ6 for Redditch centre stand? I got some for the indian replacement stand, but they ain't Whitworth!



I will also need a tap to do the indian stand...

This may or may not help:



http://www.thenippleshop.co.uk/acatalog ... ue_v71.pdf

it's probably 1/4 BSP then, although there is a chance that it could be BSF or UNC?



They look coarse like a whitworth, but not quite the same thread.

But out hosts also do the right angled...


TC/PZ65

GREASE NIPPLE, 1/4bsf angled

which is BSF . Bugger.

The Zeus book says 1/4 BSF is 26tpi and 1/4 BSP is 19tpi whereas 1/4 Whitworth is 20tpi, then there's 1/4-28UNF and 1/4-20UNC with a different core dia to Whitworth. BSP can be BSPP (parallel) or BSPT (tapered).

So I don't need to consider BA and metric? Well, that's a comfort then!



I going to be back briefly (in Paris at moment) and have one of those whit/unc thread gauges, that should tell me the TPI.

¼ BSF has a thread of 26tpi; the same as ¼ BSC (Cycle thread). ¼ BSP (Gas) has a thread OD of 3/8 inch. (To calculate thread OD with BSP add ¼ inch in each case to the specified size.)

Did you mean add 1/4 or qadd 1/8? cos a 1/4 pipe that measures 3/8 has an 1/8 added?



I am grateful for all the info guys, but oh my poor head!

I gave tpi from the Zeus book (thread and tapping sizes) but forgot BSP is sized on the pipe not the screw thread, oops. "1/4 BSP" is indeed 0.518-in O.D. Smallest listed in the book is 1/8 BSP which is 0.385-in O.D. (13/32 O.D.P.) and 28 tpi. Pipe doesn't generally come smaller than 1/8-in O.D so guess nipple would be BSF although I have seen them with tapered threads.



BA threads were originally for industrial model making by toolmakers (scaled down pre-production etc) but did get used for electrical fixings, they're actually odd-ball metric, 0BA is 6mm O.D.



Use thread gauges?

In other words a 1/8-BSP is roughly 3/8 O.D. as it needs 1/8-in wall thickness for the threads. A grease nipple does not have a pipe running through it.