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View Full Version : Garand receiver : machinist nightmare?


Kayser
November 21, 2005, 09:53 PM
So I'm staring at the various drawings of the M1 Garand receiver ( http://www.nicolausassociates.com/ ).

I'm no machinist, but I've seen a blueprint or two in my day. Am I wrong in being appalled at the complexity of said receiver? The Garand itself is of course a "parts rich" experience :) , but the receiver just seems like something ol' Johnny came up with in a fever dream.

How the heck did they ever crank out so many of those things?

Jim Watson
November 21, 2005, 11:34 PM
There is an article somewhere or another that explains that Mr Garand had worked for one of the tool companies, Browne and Sharpe, I think. So he designed his rifle to be efficiently manufactured by the leading new machine tool technology of the time... broaching. An M1 receiver has very few mill cuts, everything possible was done by broaches. What EDM is now, the precision broach was then.

Kayser
November 22, 2005, 12:08 AM
Broaching, eh? I guess that makes sense. From the front and the top, it is a big mess of slots (broaching is sort of like a deluxe scroll saw operation, right?). Still though, the sheer number of dimensions and measurements implies a boatload of individual machining operations. Tons of radii, flanges and assorted other doodads :)

James K
November 22, 2005, 06:48 PM
That kind of complexity was considered normal in the gun industry in those days, and machinists took it in stride. Broaching is an operation where a tool with cutting heads of increasing size is driven through the work. The area of the M1 receiver where the clip goes in and where the follower moves up and down was broached, so all those vertical cuts were made in one pass.

The M1 used some interesting production techniques, some of which were developed just for that rifle.

When production got rolling, the rifles poured out the door, but it did take time to get up to speed. The slow rate of M1 production in the early days (only 240,000 by the end of 1940) was one reason for the Army contracting with Remington for more M1903 rifles. (The other reason was FDR sending 1.1 million M1917 rifles, virtually the whole war reserve, to England in 1940.)

Jim

Unclenick
November 22, 2005, 08:15 PM
In Hatcher's Book of the Garand, I believe Hatcher mentions that Garand himself had to show the tool makers how to make the tools and setups that performed some of the receiver machining operations. They couldn't figure it out, either. But "parts rich" is not quite apropos. One of several reasons the Garand was chosen over the Pederson and Thompson entries into the semi-automatic main battle rifle design competition was that it had fewer than 70 parts, while the others had over 100!

Nick

James K
November 22, 2005, 08:41 PM
"Parts rich" the M1 rifle isn't. Garand had the knack of making one part perform more than one function, which meant that some parts were complex, but the gun overall is remarkably simple. For comparison, take a look at a G.43 or a Johnson if you want to see "parts rich", plus disassembling beyond field strip is in the "not recommended" category.

Jim

Garand Guy
November 23, 2005, 11:17 PM
The innards of that gun boggle my mind. I'd love to see some of the prints for the Garand, but I'm too cheap to buy the book. (And, yes, I am a Machinist)

mfree
November 29, 2005, 04:00 PM
Hrmm, I'm looking at broaching machines and it seems like the reciever would almost be finished after 2-3 broaching operations. No wonder they used it :)

Unclenick
November 30, 2005, 05:22 PM
It is a faster alternative to milling in many production situations, such as putting keyways in shafts. It can't do the threads, but hey, who'se counting?

Nick