Common Knowledge or Received Wisdom?

[Smellymarkfive]

Lining up the screw holes is one of my least favorite things to tinker with. The first time I ever did it I used the "if I just use a bigger hammer" technique and bent the screw.
Murphy's law ..............will go wrong.
My father was an engineer in the coal mines until the 80s, they were expected to experiment with equipment or systems in small ways and would be paid small amounts for innovations. Did the army have any similar programs?

[Peter Laidler]

In the UK Military we have/had a system called GEMS for suggestions that you would write-up and submit in a simple format. But nothing that you'd experiment with on your bench that would see service without trials etc.

I am imagining yoiur dad experimenting with some sort of extraction pump in a mine only to find later that the new filter was good but NOT good with some hazzardous gas and.......... Nope, we didn't do it like that. The team that oversaw suggestions had a big sign in the office that read 'NEVER FORGET THE BIGGER PICTURE'

[Smellymarkfive]

What was the big picture for them?

[Peter Laidler]

Since you asked.......... There was a suggestion that to save Mk3 Bren butts getting a constant battering around the side sling swivel that a top mounted sling swivel be attached to the top of the butt plate - jusy like the GPMG. A fantastic idea, well liked, simple and meant that the GPMG/L7 sling could also be used too.

But during the investigation it was found that all of the butt recesses in the Armoury racks were made for the ORIGINAL brens and butt plates. So as soon as you dropped the guns with the modified butt plates into the old butt racks, the nice new sling loops atttached to the modified butts bent over and broke off. Someone hadn't thought of the bigger picture............

[Richard Hare]

Peter,

Sort of reminds me of the saying, "In theory, theory and practice are the same. In practice, they are different" !

[Bruce_in_Oz]

As for keeping the boss for the cut-off:

The manufacturing process had a LOT to do with what features ended up on the finished product.

Think Nose-caps: the "boss" for the piling swivel, with or without holes and threads, remained LONG after piling swivels were abolished.

The trick was that every component on the rifle was made on fixed jigs in a long series of machines, each machine making ONE cut or ONE hole and EACH stage being individually gauged.. That is how ALL "mass-production" was done until well into the 20th Century.

"Punch-card" controlled machines, interestingly derived from the cotton processing and weaving machinery invented by a bloke called Whitney (as in Pratt and Whitney) started to change things in the 19th Century. However, it wasn't until the 1940s that things started to really change.

Now we have multi-axis CNC machining centres that incorporate their own metrology probes so that not only can EVERY stage be measured, but, as tool-wear induced errors start to occur, the system AJUSTS the tool setting and path to cut to the correct dimensions. Big bucks? Yep! But such machines can run 'round the clock churning out parts of incredible precision.

It is entirely likely that the boss for the cut-off was retained in the lll* because some other machining operation used it as a reference surface or a clamping point.

If somebody ever finds the Process Books for the manufacture of the SMLE series, it will be explained in there. (If someone DOES ever get their sticky paws on said documents, I am up for a copy.)

[Peter Laidler]

That's dead right Bruce. I often mention 60's car body production where a slight make-over, such as adding reversing lights to an MGB body in production or changing something else to create a different look will cost hundreds of thousands of £££££'s in tooling changes. The ribbed gas cylinder in Brens to dissipate heat quickly was a total waste of time and served no useful purpose but it remained/were retained on Canadian Mk1 guns because these ribs were used in production as a multi purpose holding medium for other maching processes.

[Smellymarkfive]

There's a 1986 SMLE listed on gb, those books must still be kicking around. I wonder what happened to the Ishapore machinery when they shut down production? As anyone ever visited RFI?
Great insights into manufacturing and redesign guys, makes me appreciate the effort that went into the Jungle Carbine a lot more.

[Steve H. in N.Y.]

RFI's old machinery is evidently still in use.

Rifle Factory Ishapore welcomes you

Click on ".315 Sporting Rifle" under Civil Weapons.

[Smellymarkfive]

That's cool! Do you think it has a cut off?