What size are my nipples

Hi all

i am trying to find replacement oil nipples for my Pultra 17/70 I think the thread is 0 BA because a tap seems to thread in but is there anything else that is that close that they could be , also I am having trouble locating 0BA nipples most seem to be 2BA .

Thanks Dell

0 BA and 1/4" BSF are dangerously close in size and pitch. 14 thou difference in outside diameter, 12 thou in core diameter, 0.38 tpi difference in pitch. 0 BA being smaller and finer.

Depending on the tolerances involved both will screw onto the other with varying degrees of ease and slack. Despite the difference in thread form. Such mis-fits dangerously reduce the ultimate tensile strength of the joint so pull out stresses will be much lower, probably around 1/4 of a properly mated pair.

Clive

M6 is the same size and pitch as 0BA; just the thread angles are different.

Nearly choked on my cup of tea when I read the title of the thread!

But the OP is Dell Boy?

Thanks for reply’s

I thought when I wrote title I would get some quick looks and hopefully replies.

Dell

0BA, 1/4" BSF, 1/4" UNF, 6mmX1 all posible. How many do you need, Straight,45* and 90*. Noel.'

The answer, as usual, is 'it all depends'. This time, identifying a thread depends first on where it was made, and secondly, when.

Anything made in North America will generally have 'unified' threads unless it was made before WW2 or after 2000.
Before, there were SAE threads and American Threads, mostly the same as unified. A clue is that the hexagons fit AF (inch) spanners. After, there might be Metric or even ISO metric threads and mm spanner sizes.

Europe except UK, and Japan, will be metric in one form or another, and post ww2 generally ISO metric.

The UK has a wide range of options, with Whitworth and BSF etc up to about 1950, then Unified, and Metric from about 1990. BA is rather a special case, still in UK use for some things, mainly electrical switches, plugs etc, and with their own range of spanners.

The main clue, I suggest, for grease nipples is the size of the relevant spanner.

Sorry - if it was easy you would be taught it at school.

Cheers, Tim

.

There is a high probability that a Pultra 17/70 was made in England

0BA does seem most likely to me, Dell …

When you have identified the thread with more confidence, try here:

**LINK** : https://www.hle.co.uk

MichaelG.

Spanner sizes?

Measured across flats in ascending order

M6................0.394"........................10.00 mm

0 BA.............0.413"........................10.50 mm

1/4" UNF.......0.438".........7/16".......11.11 mm

1/4" BSF.......0.525"........................13.34 mm

(assuming the spreadsheet I found ages ago is right)

Of course grease and oil nipples often use undersize hexagons.

BSF marginally more likely on a Pultra think.

Clive

Edited By Clive Foster on 03/04/2022 18:59:24

It is a 1940’s Pultra made in Manchester uk and a 2BA spanner is a good fit to the hex and most of the small nuts to adjust the crosslide gibb are BA that what makes me think it’s BA but I can’t find anyone selling any let alone brass ones that I would prefer , I have two 17/70’s to do so I need 4 and I have managed to find the paint code to the original cream colour.

id' go for 0ba as it would not be m6 in 1940s Britain

So buy M6 Iif you can get them) and run an 0ba die down, it's hardy a critical holding thread

Found some 6 mm that are similar looking but if I can’t find 0BA I will give them a try not a lot of money and as Duncan said it’s not exactly critical.

⬆️ Wot e sez. Don't overcomplicate it.

Edited By Peter Greene 🇨🇦 on 03/04/2022 19:24:39

I doubt if this is any help … but it may be of interest:

I am almost sure that the ‘Garland’ oilers illustrated on this page are original :

**LINK**

http://www.lathes.co.uk/pultra1750photoessay/page2.html

and that the oilers shown here bear the same Patent number:

**LINK**

https://www.vintageccm.com/content/ccm-nickel-etc

Which leads us to:

**LINK**

https://worldwide.espacenet.com/patent/search?q=pn%3DGB576408A

MichaelG.

Edited By Michael Gilligan on 03/04/2022 22:34:07

Hi Noel

i need 4 straight 2 for each lathe.

Dell

I have a large range though no 0 BA. Ihave sent you a PM. Noel

Further to Clive's helpful list of spanner sizes, there is 1/8 Whitworth -

0.340 inches = 8.636 mm.

This is the nominal size of the hexagon, so in practice it might be rather smaller. Stahlwille say their 1/8W spanners are (or rather were, sadly) 8.70 - 8.80 mm between flats.

I'm sorry I did not add the size details to my original response - I was imagining that engineers might have the spanners to hand. [The lowest form of wit, I suggest, is better than no wit at all.]

As regards a source of old-fashioned-sized nipples, I would try the various suppliers of stuff for vintage cars and motor bicycles. They tend to have old-stock supplies for restoration pedants, but some of these firms, organised by owners clubs, limit their clients to club members only.

Cheers, Tim

Not sure, I never checked them !