"The Enfield inch" when an inch is not an inch!

[CINDERS]

Just brought this and had a quick read very interesting and explains allot of why things are the way they are and the Pratt & Whitney connection worth getting, probably cheaper on kindle if you are not into books.

Peter may be able to expound on why the issue was not really admitted to but oh boy I wish I had one of those first pattern rifles sent over with the sealed drawings.

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[Badger]

Ian has it for sale here:

Ian Skennerton's Reprints (click here)

Attachment 62773
(Click PIC to Enlarge)

It's about 1/2 way down the list...

Regards,
Doug

[Peter Laidler]

To be really honest I didn't know there was a different 'Enfield' measurement until I was well into my apprenticeship! We had a precis leaflet sort of thing informing us what threads we could 'clean-out' on any No1 rifles we ever came across to the nearest BA thread. It always seemed to work! The old No1 revolver also had some mickey mouse threads too.

[Patrick Chadwick]

- Whether or not it's useful depends on your needs

There are (or rather were) inches and inches...Like Hanoverian inches, Viennese inches etc.

It's not just academic. I have a Hanoverian muzzle-loader rifle and a Viennese revolver. Both made to inch dimensions. In mm the sizes are weird. For instance, the barrel length of my M. 70/74 Gasser revolver is 184.4 mm - very odd - or 7.26" (imperial) - no it's not supposed to be 7-1/4"!
In fact, it is 7.000 VIENNESE INCHES.
Of course, you need to know that the Viennese inch (used until 1871) was 26,3401mm. Divided into 12 lines of 2.195mm. Which in their turn were divided into 12 points of 0.182917mm.

Armed with this knowledge, a pocket calculator, and a bit of patience, the oddball cylinder diameter of 48.32mm becomes a straightforward 1inch 10 lines - Viennese!

Fortunately, mid-19th C. European gunmakers appear to have used mostly Whitworth threads, at least for serious items like breech plugs and barrel threads. This was, of course, before the Americans had a bad attack of the "not invented here" syndrome and came up with Sellers threads to confuse the rest of the world.

So with a discrepancy of only 0.0003 between the Enfield and imperial inches, I reckon you Enfield types have it easy!

[englishman_ca]

0.0003 inches is a measurement often known as one tenth of a coontair

[Patrick Chadwick]

How much is that in gnat's whiskers (imperial gnats, of course)?

[Peter Laidler]

There is also another imperial measurement used in the large workshops in the Army. 'A gnats knacker'. As in '.....ere......, skim a gnats knacker of the edge of this will you?' We had another to describe a fit that was a bit sloppy too '........ like throwing a sausage down the high street'. Has anyone encountered centinches yet?

[Simon P]

Has anyone encountered centinches yet?

We have had 1000s of engineering railway drawings updated from the original blue prints some going back to the 1930s in to CAD, and we do see converted metric drawings with the occasional decimal measurement remaining.

One of these was "chains", I suppose the chap didn't know what it was and left the original term... for 22yds

[browningautorifle]

"chains"

My Grandfather used to speak in the old measurements. Rods, chains...so forth.

[Aussie48]

Well I have to admit that I am either too old or too stubborn to change my way of measuring things, I was an Electrical Fitter Mechanic by trade and everything was feet, inches and thous. When I go to buy bolts it is always 6 x 4 1/2" Whitworth Hex heads in high tensile please and they then try and convert it to that useless Poxy Metric system.