The floors of these machine shops were often formed with a surface of maple wood blocks placed vertically (with the grain running up and down) on top of a reinforced concrete base.

I worked for several years at IBM's factory site in Poughkeepsie, and the floors were built this way. They are remarkably stable.

I don't think that I've ever seen an article about Luger factory manufacturing engineering or machining similar to the Colt M1911 article. I believe that there is documentation of the process steps and labor costs. The new book on Mauser by Gerben (Vlim) and Mauro contains some of this material, but it's not for Lugers.

BTW, my grandfather was a Swedish machinist working around 1900 to 1950 in Chicago. He made industrial sewing machines for a company called "Union Special". We had a small machine shop in the basement where I grew up, so some of this is definitely in my genetic makeup...

He was rather clever in spacial conceptualization, and made a number of special tools that helped him improve the speed and quality of his production. As a result, he worked continuously through the American depression in the 1930's. The machines were still in demand, and he was simply better at producing them than his co-workers...

This is one of my favorite photographs...

PureTexan, chickenthief, knowing how and doing it are two way different things. But go back and look at SIGP2101's Mauserwerke photos. In one photo they have two guys at two machines and they are observing their work through magnification optics built into the machines. I recall being struck by that because I had never seen such machines in any machine shop, then it struck me, some of these skills must require watchmakers and these are the kinds of machines watchmakers must use. Talk about a forgotten art! Like you said, I could not imagine drilling a 1mm hole 1 cm deep and then turning it into a broached, rectangular hole 5 mm long by 1 mm wide. If my life depended on it.

Thanks, mrerick. Interesting tidbit about the floors at IBM. I figured the standard had been bolted to a slab and then grouted since early on. Not so, it would seem.

To think, we once had a country full of folks like your family who built not only handguns but rotary airplane engines, tanks, bombers, etc. and won two wars. What happened? I guess I better stop here or I will get into politics.

SIGP2101, thanks for the tip about hovering. I guess my Ipad didn't do that. It didn't hit me until just now what that photo in the last of the Colt series was. That "bank vault looking contraption "behind" the machine? Is that an indexing tool head? So turning it connects a new tool to the drive? Incredible. 100 years before CNC...

That is exactly what it is/was. On the back of the picture:
"The use of the revolver frame jigging machine is demonstrated by a Colt worker. This machine could cut both the interior and exterior surfaces of a revolver frame. The inner hub of the machine is engraved "Col. Saml. Colt Hartford Ct." The employee wears a unique hat that is square at the top and seems to be made of folded paper.

Museum of Connecticut History, Accession 2002.431.01"

In essence it is a mill with multiple heads that holds various milling cutters. Fascinating, is it? Here is a bigger pic. Click on it.

Back in old days, very often, precision work (optical instruments parts for example) was done under microscope or stereoscope, todays is done through the camera lens and observations is done on monitors.

Here is one example of lathe microscope:

End grain flooring is very stable in horizontal orientation, understandable if one recalls that a board will swell and shrink or crush in thickness/width, but not appreciably in length. There is one exception, though. The shop floor in my high school was constructed this way, but fell victim to a leak in the roof. This swelled up the pieces, which had nowhere to go but up, causing a giant hump in the matrix. I don't remember for sure, but I think it calmed down as the material dried out again. But then it would have been loose because the grain is crushed in the vulnerable orientations by the compression and does not recover its full dimension after that.

SIG, there truly is "nothing new under the sun..."

wow lots of things learned on one post. I never thought about drilling a hole and then broaching a slot out of it. Must have been the way they did the safety slot. Bet they were some serious machinists for the time.

Paul

Broaching is about the only way to get a slot with a "square" end, or a square hole.:evilgrin:

Of course now-a-days "they" do all kinds of neat stuff with a wire EDM cutter, or water , or a laser.

Here is the one:

https://www.yumpu.com/en/document/vi...gotten-weapons

Nice , thanks!