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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. :p
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
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.
- Whether or not it's useful depends on your needs :D
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!
0.0003 inches is a measurement often known as one tenth of a coontair
How much is that in gnat's whiskers (imperial gnats, of course)?
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?
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.Quote:
Originally Posted by Peter Laidler
One of these was "chains", I suppose the chap didn't know what it was and left the original term... for 22yds
My Grandfather used to speak in the old measurements. Rods, chains...so forth.Quote:
Originally Posted by Simon P
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.
Then there is the old Clydeside 'Baw' hair measurement.
Was that the pudding bowl on the head job?
Cripes I thought a Fairie F*rt was a small measurement but obviously it is a bit like a sausage down high street and a bulls roar! still it is a good read
1ml = 1cc=1g=1cal to raise temp 1 degree Celsius. That's the usefulness of the metric system, makes life a lot easier in the lab. But I still use chains for calculating tree height/lumber, and making a cricket pitch. I did a job once and needed about 6 inches of dowel so I asked the lad to cut me a piece from a broom handle. He cut it from the middle.
Least he was half right:confused:
The old rhyme we had to learn at School (and never forgot)
12" one foot
3 feet one yard
22 yards one chain
10 chains one furlong
8 furlongs one mile
3 miles one league
And then there is the "utterly Imperial" BA system.
Well, sort of.
It is almost a direct lift from the old Swiss "Thury" system used by yodelling clock-makers. Start with "0" BA. It has a pitch of, give or take a gnats knacker, 1mm, just like M6. The form and flank angle (47.5deg) are, of course, completely different.
"1" BA is simply "0" BA multiplied by 0.9 to give to the next smallest thread. This process repeats ad infinitum (ad nauseum?).
Hence the almost incomprehensible "numbers" attendant to BA threads. I have NEVER even attempted to cut one on a lathe; metric or otherwise. just keep a set of BA taps and dies in the toybox.
An example of the "almost" relationship is the rear-sight adjustment screws on the FAL (metric)/ L1A1 (BA); VERY similar in diameter AND pitch but not close enough.
In the process of "Imperializing" the FAL to arrive at the L1A1, screws of the nearest "industry-standard" appear to have been sought, be they BA, BSF or something different like a Unified number thread or somesuch.
Remember these were the days when Vauxhall (GM UK) built engines with bolts having UNC threads but Whitworth-sized heads. Detroit-designed motors meant to be worked on by UK mechanics with "UK standard" tools.
So that's the reason! I had a Vauxhall in 1963 or thereabouts, always thought somebody had their head in a dark place when it was designed. Sounds reasonable, except that I'm in the States and standard tools here still didn't fit! But then, the whole car was weird.Quote:
Originally Posted by Bruce_in_Oz
My dad had one for a short time in the '60's too...I even thought they were strange then.
And the next increment of measurement up from a gnats knacker is a gnats cock:D
As a gunsmith I can work happily in metric, Imperial, or a combination of both, but I tend to do all my design drawings in metric. As for the Enfield Inch; it is not worth worrying about as the difference is way smaller than any normal manufacturing tolerance. Curiously, the US, which is the last bastion of Imperial measurements, has only one official system of weights and measures, which is the Metric system and was adopted by Congress in the 1860's (probably the reason they don't use it much!). I have a 1991 GMC pickup which is made with a combination of metric and Imperial measurements!
I shared this thread with my buddy, Aron, who collects military guns from all over. He wrote me back:
"I expect anything older and English to be different. Russians are similar and if you own older pre 1930 Russian guns, they are calibrated in arshins or .78 yards. You will see reference to 3 line rifles sometimes and a line ended up .1 inch so that worked out perfect...a 3 line rifle is 30 cal."
"When I collected and rode old motorcycles and had a 1963 Triumph. I had to buy a set of Whitworth sockets and tools. Plus, my Harleys were all "American normal" with the right hand clutch and left hand brake and the feet were left foot shift and right brake. I would get on my Triumph and all was reversed. Made for some scary drives and one 2mph accident that messed up my leg."
So much for "standards" in the past. No wonder ISO is so prevalent today. In my profession (strategic alliances), recently the Brits were developing standards for collaboration across organizational boundaries. Fortunately and wisely, they asked us on the other side of the pond to contribute our thoughts, knowing we had made a lot of progress on this complex human and organizational issues. The result was not a compromise, but a higher level of thinking and more practical approaches that spanned many cultures. That's the best way to innovate -- synergize differences in thinking. Many of the technical innovations from WWII came from the cross-pollination of Commonwealth and American thinking. It helped us win the war.
Can you imagine what it was like as a 60's apprentice where every bit of equipment we had was a different thread and we had to learn them all. It was chaotic. Some of the early Centurions were BSF and BSW until the threads changed to Unified.......... but only where new equipment replaced the old so there was a mix of threads. Unified turrets on a BS boat (the bottom section of the tank from turret downwards) Number and letter drills to suit the tapping diameters of these various threads and................. The best was instruments where generally it was all BA., Then at uni when suddenly it was all in metric........ Like Woodsy says, the Enfield inch was almost academic.
If you have a Norton, it's STILL a mix of everything!
Vauxhalls! God help me: I had TWO of the things.
The first was a 1950 "Wyvern" with REAL leather upholstery, front doors that opened the wrong way, windows that simply pushed up and down, swing-out "wing" indicators in the door pillar, 525 x 16 tyres (NOT good in the wet) and a raging 12 horsepower up front. I got rid of it after "bits" (exhaust valves, gear linkages, etc. started "breaking" with monotonous regularity. Dropping the head of an exhaust valve whilst the pistons are in action is an interesting experience, to say the least. Fortunately, my late father, being a good mechanic, knew where there was a spare engine. Into his shed; delete dead engine, insert "working" one.
The Wyvern was off-loaded on a younger brother of an old school-mate and I then "graduated" to a Vauxhall "Viva" of "mid-60's" vintage, a "hand-me-down" from my older sister..
Oddly enough, IT, in turn, died as a result of an exhaust valve failure as well; only at considerably higher speed and in the middle of nowhere on the New England Tableland in New South Wales...in the middle of Winter....just as it was getting dark. That was spectacular; the displaced valve head lodged sideways into the top of the piston. This, of course, was whizzing up and down at high frequency. Piston kicks sideways in the cylinder, sleeve cracks, contents of cooling system dumped into the oil sump, great white cloud billowing out the back of rapidly and noisily de-cellerating vehicle. Exit one motor.
After a few months of riding my "dirt bike" (mud-digger" tyres are "interesting" on wet bitumen, and especially on painted road markings after any sort of rain), and public transport to get to work, I "graduated" to an XA Falcon utility, which led to another series of "interesting" motoring tales. And then there was the "re-purposed" Ford F-100 ambulance.........
Hey, you're giving your age away now Bruce! My dad swore by Vauxhall cars after being brought up on driving Bedford trucks in North Africa and up into Italy during the war. I never had one though.........
When we were young, he used to drive his 1961 Vauxhall Victor plus mum and two kids to Spain every year for our holidays (with our friends in a Hillman Minx and small trailer shared between both cars). My dad also did a complete head de-coke on the camping site!
That's a long way to go for an engine service; I'll bet your Mum was thrilled.
All of this reminiscing!
Could rapidly descend to something Pythonesque: "The Three Yorkshiremen" (living in shoebox in middle of road) spring to mind.
"Vauxhall Wyvern? Looxury! We had Vanguard Standard Eight with NO brakes and dodgy clootch!."
Funny that, my first car was a Standard Eight.