Thursday, June 7, 2012

We used to make things in this country. #80: Bren Guns & The John Inglis Co., Toronto Ontario

After composing the "Ronnie the Bren Gun Girl" post, I started wondering just what sort of operations she and her co-workers might be doing on her lathe to make these weapons. In the Collector Grade publications book  The Bren Gun Saga by T.B. Dugelby I found the information below.

The John Inglis Company, to avoid expensive forging dies in making the body of the machine gun, flame-cut the blank from 2 1/8" plate steel. This blank weighed 38.5 lbs. This was reduced to 4.5 lbs on the finished part by 247 machining operations.
The process also entailed 18 inspection operations, 273 machining fixtures, 362 cutting tools and 740 gauges. And this was for only one part of the device. 
The work was done for the most part on standard machine tools:  grinders, drills, lathes, milling and broaching machines etc. I wonder what the percentage of rejects was.

And another view of the finished body.

 And all the parts laid out.
The book is still available.

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