This April 26, 1900, American Machinist Magazine article, by E. G. Parkhurst, describes the manufacture process used to make a Krag barrel. Although, not specifically naming the Krag or S.A., there is no doubt this 1900 article is describing the operations and steps in use at Springfield on Pratt & Whitney machines.

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It is very amazing to read about the intensive labor and operations involved in making a Krag barrel.

The complete chambering was done before a barrel was ever screwed onto a receiver. The barrel was a completely finished unit, before assembly onto an action.

(I wish the article had described  barrel 'proofing'. As I understand the process, 'proofing' was done before a barrel was rifled).

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I posted this before, but below is a link to Scientific American, an article about a year earlier then the American Machinist article. Not as detailed as your findings above, but it may compliment it to some extent. The article starts on page 267 and continues on page 330. Also, see page 323 for a picture of a Krag tested to destruction.

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Articles from the American Machinist and Scientific American showed up together in a period "Engineering Index" under Krag-Jorgensen for those seeking information on the subject back in the day on page 786.

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I have a tough time reading in depth articles on a screen. I do a lot better with print. Just found a reference to drilling and reaming  the front sight hole. Must be another 30 caliber barrel being described, not Krag. I had thought the threading was indexed to the barrel from previous discussions but these barrels are threaded first then holes are drilled for the sights. So after threading, the barrel would be screwed into a bushing with a shoulder to get it clocked or timed correctly. all barrels get screwed into the same bushing. As that bushing wears and timing gets off it could be corrected by rotating it to bring the timing back, that is assuming the machining order here is roughly the same as done on the Krag.
I think for the Krag, I would have made the dovetail machining and rear sight drilling as part of the same set up top avoid errors of moving the barrel between operations. But that is  based on the way I think not necessarily the way it was done.

I thought the threads on my Krag barrel were lathe cut. Dragged the old barrel out and looked at it with a 7 power loop and I am not sure. Some of the marks look like conventional single point lathe turning and some look like they could be milled as described along with the figure 12 of a thread milling machine.
I thought thread milling was a later invention. Live and learn. Even if this is not the Krag operation described it is very informative as to what was being done in that time period.

FredC wrote on Apr 18^th, 2019 at 2:07pm:

. . . Just found a reference to drilling and reaming  the front sight hole. Must be another 30 caliber barrel being described, not Krag. . .

I suspect the hole in question is for the blade retaining pin - drilled straight then reamed to the taper that has frustrated so many who attempt removal in the wrong direction. :-X

Parashooter wrote on Apr 18^th, 2019 at 3:13pm:

FredC wrote on Apr 18th, 2019 at 2:07pm: . . . Just found a reference to drilling and reaming  the front sight hole. Must be another 30 caliber barrel being described, not Krag. . . I suspect the hole in question is for the blade retaining pin - drilled straight then reamed to the taper that has frustrated so many who attempt removal in the wrong direction. :-X

If so then the mill cut and soldering the front base would have already been installed in a separate timed or clocked operation. Possible, I guess. Too, bad all the ones that worked there are dead and can not solve the puzzle.
The article did mention drilling with a sensitive drill then reaming. If the reaming was with a tapered reamer that would fit and this could be Krag barrels described.   ?????
Went back and looked for a drawing of the drilling machine, not included, if it had been it might have had revealing clues.

Parashooter,
Went back and looked at the reamers and they sure look like 30/40. 1900 is probably too early to be tooling up for the 03-A3 Springfield.

FredC wrote on Apr 18^th, 2019 at 4:06pm:

Parashooter, Went back and looked at the reamers and they sure look like 30/40. 1900 is probably too early to be tooling up for the 03-A3 Springfield.

The US Krag front sight base has a transverse hole for a tiny pin that retains the front sight blade (visible at top of attached image). What has this to do with the 03-A3?

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Parashoooter,
I was actually agreeing with you the machinery discussed in the article is probably for the Krag. I thought they might have been tooling up in 1900 for the 03A3, but your pointing out the hole in the Krag front sight base makes it look very probable all the machinery is for Krags.

If it had been me I would have finished all that last bit of machine work (dove tail and rear sight holes) in one operation and soldered a finished base to the barrel later. They may have had a good reason for not doing it that way. Big whoopsie on my part.

FredC wrote on Apr 18^th, 2019 at 5:14pm:

. . . I thought they might have been tooling up in 1900 for the 03A3 . . . If it had been me I would have finished all that last bit of machine work (dove tail and rear sight holes) in one operation and soldered a finished base to the barrel later. They may have had a good reason for not doing it that way. . .

That would have been a very long lead time. The 03A3 wasn't developed until 1942.

The slot and pin hole for the blade would have been liable to distortion during the brazing (not soldering) and milling of the base. Leaving these operations until later ensures the blade and pin will install properly. 

The 1st (of three)"American Machinist Magazine" articles, describing Springfield Armory manufacture of the Krag, dated March 22, 1900, mentioned 10 Pratt & Whitney rifling machines of the latest pattern.

The article promised: "The tools used in this work will be fully described in an article soon to be published, and need not, therefore, be further referred to at this time".

I believe the above, April 26, 1900, article that I posted, to be the 'promised' article. It appears to describe the manufacture steps used on Krag barrels.

I understood the front-sight procedures the same as 'Parashooter' did and figured the front-sight hole was for the blade pin.

I believe that the front-sight base becomes the 'fixed reference point' for other operations: barrel index-mark, timed barrel threads, extractor-slot, front-blade slot & pin hole, and rear-sight holes.

(The barrel breech is 'faced' prior to final barrel profile machining - operation 12. The front-sight - operation 15, is installed, brazed and shaped, after barrel is profiled and outside polished - operation 14).

The described 'Perry system' is an interesting process. (I never imagined).
Preparatory to 'turning' the outside contour of the barrel, a steel collar was positioned around the middle of the rough barrel and 'soldered' in place with 'molten' type-metal. This structure served as an interim support-bearing during machining of the exterior barrel profile.
(The outside of the barrel took shape and was polished, after finish-reaming of the bore, but before the rifling process.

After rifling, but before 'Browning', the barrel is chambered with rough, mid, and finish reamers.

I will never view a Krag barrel the same again. An amazing amount of labor went in to each one. Barrels were not made like we would make them today.
They were intended to be interchangeable - as best I can figure.

(Thanks to Knute1, for bringing American Machinist Magazine articles to our attention)!

Parashooter,
You got me again, looked it up on wiki and I should have said M1903. Some of the early design and testing was done in 1900 of models that led up to the M1903. Not sure if I ever held any of the 03 Springfield in my hand. Got 2 1917 Enfields and 2 Krags and am forgetting stuff faster than I can learn it.

BR,
You may be right on the sight before the threads. On the far right of the spindle tube (on the threading machine) there appears to be some hardware that may be for aligning the sight base. If this guess is correct there would have been a different spindle or tube for rifles and carbines maybe different but similar machines. 
If you looked at enough sight bases you might be able to figure out which side the screw tightened to align the sight for threading and maybe the rear sight drilling and extractor cut. Assuming all work was indexed from the sight base, it would have been from one side or the other not a theoretical center of the base.
From the tone of the article Pratt & Whitney did not build all the equipment. More details would have answered a lot of the questions we have asked.

A year after Edward Granville Parkhurst wrote this article, he passed away at the age of 71. American Machinist documented his life in their 8/22/01 periodical (page 955 in the link below).

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Knute - Another interesting find!

FredC wrote on Apr 18^th, 2019 at 11:01pm:

Parashooter, You got me again, looked it up on wiki and I should have said M1903. Some of the early design and testing was done in 1900 of models that led up to the M1903.

I figured you were referring to the early 1903.  I suspected that in saying 03-A3, you were actually referring to 30-03, which was the first (failed) cartridge fielded for the very early 1903 Springfields. 

FWIW, I find all of this simply fascinating!  If only we could find that Way-Back machine and take a field trip back in time to when the Krags were new!

Here are (4) video clips of a Pratt & Whitney Sine Bar Rifling Machine circa 1900 (No. 2?) running. It sure must have been loud with a room full of these running. I'm not sure if they had it fully set up. When the rifling tool reaches the end of its stroke (left end) it is suppose to toggle an indexer bar, but it didn't appear to be activated. Appears they had an old section of an octagon muzzleloader barrel set up just to initially play with the machine.

Clip 1:
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Clip 2:
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Clip3 :
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Clip 4:
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Great article, thank you for sharing,

I bumped this old thread today because it covers much about Krag barrel manufacture in early 1900's.

Knute had posted (in Chit-Chat, yesterday) a brief 1901 article from "Hunting and Fishing", which touched on some of this.