Asymmetry is not an illusion. It is about the end of the cut produced by the cutting wheel profile.
Yes, but that's the illusion. They are all straight cuts perpendicular to the radius. If you had the taper in the cut from the wheel, then there is no way you couldn't have them look the way they do. If they are straight, they are either not getting shallower, or they are not perpendicular.
 
I don’t think you understand what we mean by asymmetrical. Most grenades have cuts that have a flat side the whole length of the cut and an angle on the other. Symmetrical cuts do not have the flat side to their cut.

I have both in my possession.
 
Here are some pictures to show the difference. See how the asymmetrical one has a flat cut. As you rotate it the flat cut changes from right side to left side.

The symmetrical one doesn’t have a flat cut and the ends of the cut end in a “V”.

I have been told by a major ordinance collector that the symmetrical cuts were likely made one at a time. The asymmetrical cuts could be made two at a time, having to rotate the piece less times and reducing machine time. Let me find the cutting wheel diagram and post it.


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Here are the images from inert-ord.net that show the proposed method for cutting the asymmetrical grooves as well as a rotated view of the asymmetrical cuts. I hope these help you to understand what we meant by asymmetrical.

C6494CD7-D954-4583-ACDD-4828B7017E46.jpeg
E0E4BB6A-6B3B-49C6-896A-10C291FF7854.jpeg
 
Here are some pictures to show the difference. See how the asymmetrical one has a flat cut. As you rotate it the flat cut changes from right side to left side.

The symmetrical one doesn’t have a flat cut and the ends of the cut end in a “V”.

I have been told by a major ordinance collector that the symmetrical cuts were likely made one at a time. The asymmetrical cuts could be made two at a time, having to rotate the piece less times and reducing machine time. Let me find the cutting wheel diagram and post it.


View attachment 1011330 View attachment 1011331 View attachment 1011332 View attachment 1011333 View attachment 1011334 View attachment 1011335 View attachment 1011336 View attachment 1011337 View attachment 1011338
I'm ready for some sweet measurements from those whenever you are ;)
 
Although they were still definitely cut from the side.

Actually maybe/probably not. The guy in the video is using a vertical milling machine , eg.

vert..jpeg


I have heard that this type of mill was invented in the late 19th cent. for rifling gun barrels, personally I'm not so sure about this (was invented late 19th.C.) but I do know that the more standard milling machine in the early 2oth.C. , esp in heavy industry, was the horizontal type. eg's

horizon1.jpeg



Seen set up for gear cutting.

horizon2.jpeg


Both types were used side by side in industry for a very long time & it is only in the last 40-50yrs (that makes me feel old) that the vertical has gained supremacy.

Which type was used for this exact job - I don't know. Given we're talking 1915 my money would be on the horizontal.
 
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Actually maybe/probably not. The guy in the video is using a vertical milling machine , eg.

View attachment 1011537

I have heard that is that this type of mill was invented in the late 19th cent. for rifling gun barrels, personally I'm not so sure about this (was invented late 19th.C.) but I do know that the more standard milling machine in the early 2oth.C. , esp in heavy industry, was the horizontal type. eg's

View attachment 1011538


Seen set up for gear cutting.

View attachment 1011540

Both types were used side by side in industry for a very long time & it is only in the last 40-50yrs (that makes me feel old) that the vertical has gained supremacy.

Which type was used for this exact job - I don't know. Given we're talking 1915 my money would be on the horizontal.
Oh that’s interesting, I’ve never seen one of those. I guess it might be recorded somewhere what machines the Cotton Powder Company used. Or if the company that took over production stamped their name on the grenade maybe it can be determined if the change was due to the machines each company used.
 
Horizontal mills were once the mainstay of engineering, certainly at the time we are looking at. This type of cut is just the sort of thing they are good for, indeed better than a vertical.
If I had to increase my bet I say that the this cut form was designed to accommodate the machinery available rather than the other way round.
Getting hard to give one away these days, verticals are so much more versatile in a small workshop.
 
Here are the images from inert-ord.net that show the proposed method for cutting the asymmetrical grooves as well as a rotated view of the asymmetrical cuts. I hope these help you to understand what we meant by asymmetrical.

View attachment 1011370 View attachment 1011371

I just want to say how cool it is to see a grenade with such a straight beveled first ring! I've only seen the ones like your darker grenade, with a flat edge. How did you get the finishes on those? They're both dark, but one looks almost painted and the other looks lightly blued :D
 
I just want to say how cool it is to see a grenade with such a straight beveled first ring! I've only seen the ones like your darker grenade, with a flat edge. How did you get the finishes on those? They're both dark, but one looks almost painted and the other looks lightly blued :D

As far as I know, all of Chris's grenades are natural patina.

Here are mine... all untouched in terms of stripping, etc.


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Phew, I recognize those! (spending too much time on this forum)

I also suppose I've only come across a handful in my lifetime and my most recent (with brown paint and rust) was the nicest I've seen, I forget they ARE out there in museum condition! My MK2 is brown but in this condition as well
 
From what I see in these pictures (inc condition) these are blacked at the factory, most likely blacking salt bath. Painting would be far less hazardous to the operator & doable by unskilled labour hence speeding things up, indicating a production method change. Could be differing factory practice also (there were more than one?).
 
Here are some pictures to show the difference. See how the asymmetrical one has a flat cut. As you rotate it the flat cut changes from right side to left side.

The symmetrical one doesn’t have a flat cut and the ends of the cut end in a “V”.

I have been told by a major ordinance collector that the symmetrical cuts were likely made one at a time. The asymmetrical cuts could be made two at a time, having to rotate the piece less times and reducing machine time. Let me find the cutting wheel diagram and post it.


View attachment 1011330 View attachment 1011331 View attachment 1011332 View attachment 1011333 View attachment 1011334 View attachment 1011335 View attachment 1011336 View attachment 1011337 View attachment 1011338
As far as I know, all of Chris's grenades are natural patina.

Here are mine... all untouched in terms of stripping, etc.


View attachment 1015410

You sons of bitches! LOOK AT THOSE!!!

They look so fresh and crispy, they look like chocolate. Each one is a Prime Example. Each one. Well done guys.
 

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