very odd thread

[mini-me]

I thought after 50+years I had collected all the odd thread taps/dies I would need.

11/16x 32 TPI has got me though. Anyone got any input on its origins?

Its on one of those hand opperated Klaxons.

[R]

Don't know.
But someone on another forum not so far away sez this

Machinery's Handbook 26th edition lists:
11/16-12 UN
11/16-16 UN
11/16-20 UN
11/16-24 UNEF
11/16-28 UN
11/16-32 UN

So it almost comes down to if it hasn't been done before, someone surely will ?!!
There is a lot to be said for standardization and unification and metrification and and and .... !

[cardan]

Maybe it's a horn thing: threads on bulb horns are often large diameter, fine pitch, and whacky! But with FNs and  a Douglas in the shed, nothing surprises me. My favourite Douglas thread is 17/64-25tpi (although 3/16-27 is a close second), and the majority of threads on a veteran FN are imperial, and 2 tpi more than Whitworth, so 1/4-22, 5/16-20, 3/8-18 etc. Possibly my favourite FN thread is the 5/16-28 left and right combo on the turnbuckle that supports the magneto. None of these appear anywhere in compendiums of threads.

I suppose it was done to ensure that spare parts were purchased from the manufacturer.

By the way, weird American threads - labelled UN in R's post - are most often labelled UNS (unified special) these days.

Leon

[33d6]

Hi Leon,
A friend and I once had an entertaining evening going through an Alfred E Herbert publication on threads. Some were positively bizarre. A E Herbert did a lot of stuff for the Royal Navy who by all accounts just ordered what they thought appropriate for the job and to heck with standardisation. Things like metric pitch threads on imperial size diameters and breech block threads to suit the calibre of the gun which seemed to bear no relationship to anything.
My friend had spent his working life as a mechanical engineer for the DoD and just shrugged  saying nothing would surprise him about the Royal Navy. Apparently in their heyday they just said what they wanted and firms like A E Herbert produced it. Cost, practicality or standardisation just wasn't an issue.
In my apprenticeship days there would be the odd mutter about '!"£%^%' threads, It took a long time for it to sink in there is no such thing as a '!"£%^%' thread. It's merely one you haven't learned about yet.
But some are a bleeding mystery aren't they
PS. I have a 5/16x20 tap. Villiers used it for some obscure applications.

[cardan]

Yes I think there are interesting organisation/industry links. You mention Navy, but one I've found is firearms. In the smaller sizes, FN (full name Fabrique Nationale des Armes de Guerre - National Manufacturer of Arms of War, and makers of the Browning pistols and other armaments) used 3/16-30. Another unlisted one, but you can still find them today as the screws that hold the grip on a Luger pistol.

In 1/8, FN use 1/8-40. That BSW is 1/8-40 is, I'm sure, just a coincidence.

The machine I've been working on today is a tiller-steered three-wheeled car, with a 600cc motor above the single front wheel, built in Berlin c1907. The most common thread on the car is 10mm-16tpi. I kid you not! BSW is 3/8-16 which is close (3/8"=9.52mm), as is M10-1.5 (16 tpi is 1.6mm pitch), but these threads are really, genuinely 10mm-16tpi. As I said, nothing surprises me - in fact I love it.

Cheers

Leon

[iansoady]

When I was a Technical Apprentice in the old CEGB in the 1960s, a directive arrived from somewhere that everything had to be converted to metric. We came in one morning and in the stores all the 1/2", 3/4" etc BSW and BSF bolts / nuts had been relabelled as 12.7mm BSF etc etc. It only took a few days till they were changed back......

[R]

Thats a good one !

On a similar but different note, a letter to the local paper when everything went 'metric'.
Someone left a note out to the milkman, saying they wanted 1136cc of milk.
In the morning, there was nothing.
Later, they collared the milkman and asked what happened.
He said he didn't know what that was.
2 'metric' pints, of course.

Now, everyone (?) is wondering if brexit goes ahead, will pints and gallons come back.
As well as shillings and pence, feet and inches, rods poles perches and chains ?

[33d6]

It's now 50 years since Australia changed over to metric and that now seems to be a done deal. There's no going back there. We still have the daylight saving nutters though. You know the ones, the extra sunlight fades my curtains, it confuses the cows at milking time, and so on.

Years ago I bought a French vintage car, I thought life would be easier as it was all metric, It was then I discovered the full joy of French automobile threads, German automobile threads and modern ISOmetric threads. The metric thread world has as little logic as the imperial one.

Ain't life fun.

[Rex]

Having been taught about Imperial, Unified and metric threads at the start of my apprenticeship I never saw anything particularly strange about the Imperial ("Whitworth" for dummies) system.
Only after the advent of the Net when Americans used to crap on about Limey threads and all that old nonsense did I realise that anyone had any issues with it, but then that's Yanks..

Now, everyone (?) is wondering if brexit goes ahead, will pints and gallons come back.
As well as shillings and pence, feet and inches, rods poles perches and chains ?
 you.

You're asking tongue-in-cheek, I hope?
Nearly as bad as some at*e on TV recently asking if all the Poles are going to be rounded up and deported..

[Boo]

Contact Taff the horn specialist in Wales, He advertises in Old Bike Mart.  01792 233763
lyn.issac@tinyworld.co.uk

[mini-me]

Thanks, I have known Taff the horns for some years.

[A10 JWO]

I have a little set of Wells Brothers Little Giant in a nice box if you want to finish your collection : )