Original 1911 slide grip serrations

Hi guys,

Anybody have an original 1911, or an A1 up to the end of WW2?
The reason I ask:

In looking at the grooves on the slide at the rear, to aid in gripping during cocking, whatever you call them. To my eye, they look like they'd be shaper cuts. Thinking like an early 20th century machinist, I can't imagine they'd be anything else. (Maybe a horizontal with a gang cutter, but my logic below still tracks.)
The modern version is done on a bridgeport with square ended end mill, and the head rolled over, but the bottom of the groove is still a right angle. With a shaper, there's no reason why that would have been the case, and you could get a better grip, and sharper serrations if you made a tool with a more acute profile.

So I'm looking for someone with an early 1911 to take a look at the profile of the grip serrations. I just want to see what they did. My suspicion is that rather than looking like a bunch of roofs next to each other, it'll look more like an old sawtooth factory roof, with the 'down' cuts between the angled cuts being more-or-less at right angles to the axis of the slide.
In digging into the guts of the 1911, there are a great many things about how it was designed that make me *really* wonder what on earth Browning was smoking. Clearly, there must have been reasons, but I'd love to know what some of them were.

Anybody know what they did for those serrations early on? Or do you have one to look at?

Thanks,
Brian

It is my understanding that the grooves were broached. A cutter, mounted on some sort of shaper/planer/ram arrangement would cut all the grooves at once. The cutter would have a series of progressively deeper teeth, much like a keyway broach, and one stroke of the cutter would produce a full set of finished grooves.

Doc.

I have no idea how the serrations were machined but the bottom of the cut is perpendicular to the long axis of the slide with a forward slant to the cut to enhance gripping ability and they are sharp. The cut was triangular with the short side of the triangle toward the muzzle. The length of the entire cocking area is 1/9/32 inches with 18 serrations. You are correct that the down cuts are at right angles to the axis of the slide. They are not more or less they are at a right angle.
I am a bit curious as to the implied question regards the design of the 1911.I am not a gunsmith but the genius that John Browning was amazes me. For instance the simple magazine release on this gun not only retains and releases the magazine it provides the trigger stop.
Remember also that in Brownings early design there was no grip safety. This little addition was added because the Army wanted two safeties. This addition also got many soldiers killed because when ice snow and dirt found its way into the grip safety the gun would not fire.
As you can tell I am a great fan of the 1911A1. I hope some of this is helpful.

I cut a matching set of front serrations by using a boring bar with a tool ground to duplicate the angle by clamping the slide in a vise standing vertical and just using the boring bar as a form cutter, slowly and carefully. It was tedius, but looked fine and was a close match to the esisting rear serrations. Of course you can just buy a dovetail cutter that matches the angle of the serrations.

Brian,
I have a Rem Rand WW 2 slide you can take a look at.
Ken

kendog said:

Brian,
I have a Rem Rand WW 2 slide you can take a look at.
Ken

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Thanks Ken, I think the guy 2-3 messages above answered my question. From the dimensions he gave, I can work out the angles on the cutter, at least close enough for government work. (Unless you're coming into town? My level's still at the shop, and the vises are off the mill at the moment. The table's dead flat, and precision leveled.)

I've actually got a shaper, so I'm set there, if I decide to try doing an 'original' slide at some point. I was mostly curious to see if I was right about the profile. Doing it with a gang broach makes as much sense as anything else on the blinking thing. (actually, it *does* make sense, if you amortize the cost of the cutter over some *very* long runs.)

What I meant about Browning was that if you really look at how something is designed, you can often get a sense of how the person who designed it thought.
Looking at the manufacturing decisions of the 1911, it's very clear that Browning did *NOT* think like a modern machinist or production designer. If you look at how some of the parts are designed (like the frame) there are cuts that are harder than they have to be, and I'd really like to ask him *why*.

My favorite example is the relief hole from the bottom of the frame for the disconnector. In order to make the hole, you have to thread a long reach drillbit down the entire length of the magwell, through a cutout hole in the backstrap, and *then* make a hole in the underside of the frame, that starts on a curved slope. Oh, and it's at a 4 degree angle, fore-and-aft. I'm pretty sure I know how he did it. It involves a custom made drill bit, two entirely separate ops, and very probably a custom made *machine*, just to make the disconnector hole. My question is WHY. Most modern frames flatspot the area of the curve where the disconnector hole starts, just to avoid the problem of trying to get the long drill to start accurately against the side of a slope. He could have too. Why didn't he? (The curve is a leftover from the end of a cut done with a milling cutter, so there's no functional reason why it needs to be curved.) If the hole were at right angles to the frame, he could have done it in normal setups while it was jigged for most of the rest of the cuts on the frame.

It's a puzzle that interests me at the moment. Don't take it as me thinking he's an idiot, clearly he wasn't. But when faced with something that makes no sense to me, I try to understand why it was done the way it was. Lots of times I learn something worth knowing that way.

Thanks
Brian

For the correct angle of the factory serrations, take a look at the attached drawing.....

Another way to cut them is a custom ground flycutter in the vertical mill. That way the mill head can remain vertical and the vise swiveled if needed to make the cuts slanted. I have only cut one set of serrations in a GI slide front end using the method, but it was no problem.

RWO

It appears to me that Mr Browning was in the business of designing firearms for the people who really needed the very best firearms available. He seems to have been confident that the machinists and toolmakers of his time could produce any mechanism he thought necessary. Time has proven him right. Regards, Clark

Please do not take my comment as an indication that you thought Mr Browning an idiot, it was not intended as such. I was merely curious. You have explained it very well. I will have to take a closer look at one of my 1911A1s It appeared to me that the disconnecter hole was in fact drilled from the top of the frame on a flat surface. My question was how did he know where to drill the hole to make the entire firing sequence a perfectly timed series of actions?
Bob

r segars said:

My question was how did he know where to drill the hole to make the entire firing sequence a perfectly timed series of actions?

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I guess that didn't come from the idiot side of him.

r segars said:

My question was how did he know where to drill the hole to make the entire firing sequence a perfectly timed series of actions?
Bob

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That is what made him the Genius that he was. I stand in awe at how many patents he held, and how many of his designs were copied, even in today's age of CAD-CAM. He was a genius way ahead of his time..........

Here is a short, but interesting story on the man - John Moses Browning

This is a circa 1918 example:



Under magnification longitudinal striations are clearly visible from a broach/shaper like process- not milled.

r segars said:

......The cut was triangular with the short side of the triangle toward the muzzle.....

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That confused me at first, because you say the cut is being triangular, and then describe the orientation of what's left after taking the cut.

I would say that the cut was triangular, with the long side of the cut triangle being toward the muzzle(or, the short side of the resulting metal triangle toward the muzzle).....

In Kuhnhausen's book he mentioned that the 1911 changes slightly between different manufacturers and even years of same manufacturer.

This is from the prints, it specifies the angle. If you're trying to make it exactly like an original, pick the one you like as they did and can vary, IMO.

Trboatworks said:

This is a circa 1918 example:

View attachment 121279 View attachment 121281

Under magnification longitudinal striations are clearly visible from a broach/shaper like process- not milled.

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Outstanding! Many thanks.
-Brian

This shows some of the newer and older equipment used:

https://www.youtube.com/watch?v=4-VbDlLoQBQ&feature=youtu.be

There was a book published by Colt, I believe in the 1930s, that followed production of a Colt firearm start to finish. If I remember correctly they flipped a coin whether they would follow a revolver or pistol and the revolver won. Had it gone the other way we'd know a lot more about the auto pistols.

He'd likely know where to drill the hole by working up a jig to hold the frame just so under the drill. Lots of work getting that right I imagine, but once done... I imagine the production lines would be tooled to produce requiring the least skill possible & least time used on the part of the machine operator.

It would be interesting to know the reject rates of the various factories, perhaps moreso what were the most troublesome manufacturing steps. I imagine theres a book someplace covering that...

During WWII RCA was making a radio that had a particularly difficult hole drilled in the dial mechanism. They were made in two plants and a supervisor at one wondered how the other plant seemed to be turning them out with no difficulty while his best machinists had trouble. When asked, the foreman at the other plant said "See that woman running the drill press. She is the only one who can do it. Don't say anything or she will want a raise."

Bill

Johnny V said:

That is what made him the Genius that he was. I stand in awe at how many patents he held, and how many of his designs were copied, even in today's age of CAD-CAM. He was a genius way ahead of his time..........

Here is a short, but interesting story on the man - John Moses Browning

Click to expand...

Very interesting article about Mr Browning. Thanks for sharing.