Non-Destructive Testing

[fossilledges]

First of all, my apologies if this subject has been covered in places on the forum which I have not read. I think I have read most of the threads which mention Magnafluxing. My question is does any member have any good reading to recommend regarding non-destructive metallurgical test methods from a gunsmithing perspective. I have access to plenty of metallurgical journals which cover non-destructive testing for industry. After watching the Pedersoli factory documentary information on Youtube, I began thinking that they must track all of their stock material and do batch testing beside the standard tests as pieces leave the factory. I'm sure they, like all gun manufacturers, would consider their own testing as proprietary to the company for a number of reasons, trade and legal. When I was in graduate school doing internships at The Wallace Collection, V & A and Trinity, I knew that the conservation labs had the means to x-ray and metal particle test antique firearms but it was more about provenance and craft technique than being fit for use. Thanks for reading! --Dr. Paul

 

[Zonie]

Good luck to you in your search. The subject is probably covered in a good Gunsmithing book but I don't know where you would find one.

When it comes to "real live" situations, I've never heard of a "gunsmith" that owned Magnetic Particle Inspection equipment like a Magnaflux machine. A few of the bigger Engine Rebuilding shops do have the equipment. They use it for inspecting crankshafts, camshafts, cylinder heads and engine blocks.

Even when it comes to Penetrant inspection I've never known a gunsmith that has actual "Fluorescent Penetrant" equipment.
Almost all of them use a spray on dye penetrant method that they spray on, wipe off and then apply another spray that changes the color of whatever is left on the part. IMO, this is not nearly as effective as a true fluorescent penetrant inspection but it is better than just holding the part up next to a bright light.

As for X-ray, I can't imagine a gunsmith that could afford to buy that equipment or know how to use it. The little X-ray machines like those used by dentists are totally worthless for inspecting metal parts because they don't have enough power.
The X-ray machines used in industry for inspecting metal parts would totally destroy any living tissue exposed to them when they are operating.

A gunsmith might be able to afford Ultrasonic inspection equipment that is suitable for inspecting metal parts but I doubt they would ever have enough need for it to justify the cost. Here again, Ultrasonic inspection equipment that is suitable for inspecting metal parts like castings, etc is much more powerful than the one that doctors use to see if a gall bladder has stones or what the sex of a fetus is.

 

[fossilledges]

Thanks for your reply Jim! I didn't even consider ultrasound. When I was at the Wallace, I never witnessed a firearm being x-rayed. They used it a great deal for paintings at the V & A. Non-destructive testing was not as important as provenance and conservation of the pieces. Good X-rays were utilized all of the time to examine real versus fake in the painitng world. I don't recall hearing of any of the auction houses in London doing their own testing. I was a young student then and not paying enough attention.
I will continue to look within gunsmithing resources for references. I just retired from my practice and have most of my late father's metallurgical test equipment, dye penetrant UV and magnetic particle field kits, which I would like to gain more experience with. My mantra is "first do no harm" and I fall into the conservation camp regarding historical objects in general.I do not currently have access to an x-ray machine but consider some of the applications there with original firearms. One could gain a better understanding of what has been replaced or pieced together. Nothing replaces a good experienced eye of course, but I was just musing about the actual use of non-destructive testing for conservation and provenance of antique firearms. --Dr. Paul

 

[smoothshooter]

Thanks for your reply Jim! I didn't even consider ultrasound. When I was at the Wallace, I never witnessed a firearm being x-rayed. They used it a great deal for paintings at the V & A. Non-destructive testing was not as important as provenance and conservation of the pieces. Good X-rays were utilized all of the time to examine real versus fake in the painitng world. I don't recall hearing of any of the auction houses in London doing their own testing. I was a young student then and not paying enough attention.
I will continue to look within gunsmithing resources for references. I just retired from my practice and have most of my late father's metallurgical test equipment, dye penetrant UV and magnetic particle field kits, which I would like to gain more experience with. My mantra is "first do no harm" and I fall into the conservation camp regarding historical objects in general.I do not currently have access to an x-ray machine but consider some of the applications there with original firearms. One could gain a better understanding of what has been replaced or pieced together. Nothing replaces a good experienced eye of course, but I was just musing about the actual use of non-destructive testing for conservation and provenance of antique firearms. --Dr. Paul

I was a licensed industrial gamma radiographer for a couple of years using the radioactive “ pills “ of Iridium 192. It produces the same types images on film as X-rays do, and is used a lot where electrical power is not available.
I did “ shots “ of a couple of my loaded handguns one night, and they came out perfectly, and are quite interesting to look at.
We never had any requests to do any guns while I worked at that non-destructive testing company, but would have if requested, since the owner was a gun guy.
I cannot say what it might cost you if you went that route, but I would imagine charges might be all over the place.

 

[fossilledges]

That is very cool and interesting! Are the film images full size?

 

[Flint62Smoothie]

FWIW I have all of the modern gunsmithing books and all (that I recall) mention the various methods, but also note that one might need to partner or sub-contract to the said ‘specialty shop’ to get that work done.

Some use the diesel method on cast irons arms.

 

[fossilledges]

Yes, thanks for the reply, I have a small library of modern gunsmithing books and I cant' find any specifics to non-destructive testing. I just retired and have inherited my late father's gunsmithing tools as well as his metallurgical test equipment. He worked for ITT and did nuclear plant cooling system metallurgical testing. I grew up around the equipment so know something about magnetic particle testing, Magnafluxing and x-raying. I'm just trying to learn more. Also, these techniques are used in the art conservation field, so there may be applications to the antique firearms conservation field. Again, thanks for the reply, this is probably not a common subject. --Dr. Paul

 

[smoothshooter]

That is very cool and interesting! Are the film images full size?

Yes. The details came out even better than I expected. I can even see the anvils in the primers.
I did another one of an original flint .62 caliber English trade-type pistol made around 1800 I would guess. I was curious how a shield-shaped inlay was attached to the upper rear part of the grip behind the barrel tang. The radiographic film showed that a small tapered hole had been drilled to a depth of about 3/4 of an inch, then the shield inlay that has a small nail-type thing soldered to the back side was driven in the hole.
What was so interesting was that the tip of the small " nail" had a tiny barb on the tip which presumably bites into the wood at the bottom of the hole and keeps the nail and inlay assembly from backing out.
Pretty cool, I thought. First time I had seen anything like that.

Guess I need to get a life.

 

[Gun Tramp]

the tip of the small " nail" had a tiny barb on the tip which presumably bites into the wood at the bottom of the hole and keeps the nail and inlay assembly from backing out

That's about the neatest thing I've ever heard. Thank you, smoothshooter.

 

[fossilledges]

Thank you Smoothshooter! Your observations are very interesting. I'm thinking of several potential applications. The first is provenance, one might gain insights into how much of a gun is original or modern. The second is actual construction techniques which you described. I find that fascinating. Another thing I'm thinking of are the applications with the flintlock Ottoman and Trade pistols I enjoy, which are often a pastiches, depending on their history. I'm talking about the ones which were used and not originally proffered as hangers. Sometimes I disassemble one and look at the pile of parts and think that it is far from worth the sum of the parts. But, certainly interesting history. Your observation about the shield attachment is exactly the sort of thing that would have made my day when I was at the Wallace. Thanks! --Dr. Paul

 

[smoothshooter]

Thank you Smoothshooter! Your observations are very interesting. I'm thinking of several potential applications. The first is provenance, one might gain insights into how much of a gun is original or modern. The second is actual construction techniques which you described. I find that fascinating. Another thing I'm thinking of are the applications with the flintlock Ottoman and Trade pistols I enjoy, which are often a pastiches, depending on their history. I'm talking about the ones which were used and not originally proffered as hangers. Sometimes I disassemble one and look at the pile of parts and think that it is far from worth the sum of the parts. But, certainly interesting history. Your observation about the shield attachment is exactly the sort of thing that would have made my day when I was at the Wallace. Thanks! --Dr. Paul

I have no reason to believe the gun is anything but all original.
I bought it in 2004 from Thad Scott, a dealer in central Mississippi specializing in fine double shotguns and old muzzleloaders.
I happened to see the front of his shop ( I recognized the name from the full page ads he ran in Shotgun News all the time ) while driving through town coming back from a job one day, and stopped in. Upon entering, I saw a man in a large room kneeling on the floor laying out an assortment of Springfield and Enfield muskets, and a couple of smoothbores that were very dirty, most having a fair amount of dried mud in various places.
“ Look like battlefield pickups “ I commented.
“ I think that’s what they might be “ he replied. “ That’s one reason I bought them “
He said they had been the previous owner’s family as long as anyone could remember in a very old house put up out of the way and out of sight and apparently untouched for many years.
While watching what he was doing, I noticed an old cardboard box about two feet square nearby with some more stuff in it. I saw what appeared to be a large octagon pistol barrel with some rust on it sticking out. I asked if it was okay if I looked in the box. When he said for me to help myself I pulled the pistol out for a look. Turns out it was a flint .62 smoothbore with a barrel about 6” long, English style, in pretty good shape except for some deep pitting near the muzzle on the outside.
I asked him what he would take for it. He said he hadn’t had a chance to really look at it yet because he was mostly interested in the muskets, and had only bought the pistol and a few other guns because he had to buy all the guns or none at all as a condition of the sale.
I asked what he would have to have for the pistol. He looked up at it for about 5 seconds and said “ how about $200 ? In about 3 seconds I said it sounded good to me, and I left with it right after digging out the cash, regretting that I was out of time to look around more.
Apologize for the long story, but maybe some will find it of mild interest.

 

[fossilledges]

Wow, thanks for the history and story regarding how you acquired the pistol. I never run across great deals like that! And all the research work you have done will contribute to its provenance. Thanks for sharing! --Dr. Paul

 

[Felix the Cat]

I am aware of NDT being used on Artillery and other larger items, but usually on breech rings and similar items. In UK practice, it is assumed that material faults in barrels would be found by proof testing, which has proved to be extremely reliable over the long period it has been in use.

I know industrial X rays and Neutron ray techniques have been used to investigate ammunition. The issue is balancing penetration with suitable contrast. By controlling the Kv of the X ray tube, the frequency and "hardness" of the X rays can be varied, but this is a specialised technique to both carry out and interpret the results!

For the gunsmith, the main concern would be to monitor possible shear and cracking sites, typically around locking lugs and breech closures. Generally one of the die penetration systems is quite sufficient for this.

For muzzle loaders (remembering where we are!) this is not so much of an issue as there is only one breech closure (...the breech plug) which is normally so over engineered there should not be an issue. If you are concerned that a barrel has been overcharged, the first sign is usually a bulge or a ring. I would suggest that conventional NDT would not detect anything much on a muzzle loader that would warn of an incipient failure...

 

[fossilledges]

Thank you! Very interesting!