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John Hosford always brings his gauges and also sells them. I will probably be bringing my set also.

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Thanks, Mark. I’ll track you down.

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William: your question is not unreasonable, and I believe the answer is relevant to this discussion, which may be found toward the bottom here
https://docs.google.com/document/d/1ZIo0y746UsSRZIgRuuxwAbZjSBHitO_EanvwLYc-kGA/edit

The gun in question with the spring steel and leather handguard in place

[Linked Image from photos.smugmug.com]

"I personally measured the wall thickness of a 1906 L.C. Smith 16g No. 0E with “Good Two Rod” Damascus at .016”, 14” from the breech which [prior to having the wall thickness measured] had survived 250 2 1/2” 7/8 oz. Polywad Spred-R shells, 100 2 1/2” 7/8 oz. at 1145 fps. (about 8000 psi) loads [William Larkin Moore's], and 2 cases (500 shells) of 2 1/2” RST 3/4 oz. at 1100 fps (4,600 psi per RST) without rupture or dimensional changes."

My 3/4 oz handloads are listed in the manual at 5400 psi, a buddy chronographed the load at 1185 fps, and cases of that load have been through the gun.

The end-of-chamber MWT is .114" R (the thin barrel) and .118" L. 9" from breech is .032" R and .044" L.

It is my opinion that barrels that are thin from 12" from the breech to the muzzle (where pressures are much lower) are likely to split; not disintegrate

[Linked Image from photos.smugmug.com]

But the hand guard provides some additional safety.


Could you please share the wall thickness gauge that you use, and the end-of-chamber and 9" MWTs of your Lefevers?
Thank you. Drew Hause


BTW while digging out the evaluation, I found these end-of-chamber wall thickness numbers:
20g No. 00 Armor steel Smith .088" L and .090" R
16g No. 00 Armor steel Smith .096 L and .105 R
16g No. 0 damascus Smith .108" L and .102" R
12g No. 4 chain damascus Smith .110" L & .103" R

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My gauge. Accurate. Rigid. Repeatable. IMO, your gauge is only as good as the quality of your indicator.

I have a Manson too, but I hate it. The Manson is ok in pinch, but I really don’t like messing with the damn thing if I don’t have to.

[Linked Image from i.ibb.co]

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I use the same one, I like it and it works well.


http://www.bertramandco.com/
Booking African hunts, firearms import services

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So, all of you who own mechanical wall thickness testing devices disagree with Dewey V. ?, who says:


Mechanical Wall Thickness Gauges Are Worthless

Traditional barrel wall thickness gauges are inherently inaccurate due to the flexibility of the barrel arbors. This includes the vaunted "English Gunmaker's Style" that uses three rods mounted in a baseplate. The reason is that the arbors are solid rods that can be 14 to 18 inches in length and no matter how stiff you might think they are, they absolutely are not. They will flex measurably at the slightest provocation. This tool serves little more purpose than to impress the ignorant onlooker. It is guesswork with a dial indicator, nothing more, and was never the best tool for the job, even though it was the best that could be hoped for at a certain time. Thankfully, that time is passed. The ONLY widely available method of absolutely accurate wall thickness measurement is through the use of ultrasonic measurement. The tool that I use is the DeFelsko UTG P1 which is capable of measurement down to .008" in steel with an accuracy of .0004" (four TEN thousandths of an inch). Yes, it's expensive because actual accuracy costs, but it's worth every penny.

Here is some proof of the flexibility of the "traditional" gauge construction. The following video shows just how much movement there is in a .625" diameter water-hardening steel rod, at 16 inches unsupported length, chucked in a 5C collet in the lathe. This setup is much more rigid than any baseplate mount. The amount of deflection (a lot) versus the force applied (very little) should illustrate why ten different people will get ten different readings of the same barrel.

"But it's used in a vertical position" you say. Think about the fact that half of the barrel length is above the uppermost end of the arbor and that the inner wall of the barrel being measured MUST contact the arbor. Do you really believe that you can hold the inner wall in contact with the arbor, while not inducing ANY side load and causing it to deflect at all?

"But it's better than nothing" you say. No, erroneous information is worth exactly nothing.

"But so-and-so uses it and always has" you say. Of course, it looks snazzy, it impresses those that don't know any better and it's cheap to make. As you'd expect, it is also monumentally overpriced to buy, which further cements its "credibility" with the purchaser.




Apparently, he has so much credibility on this board when he speaks of other doublegun related topics, why not this?

Last edited by Stanton Hillis; 06/22/22 08:30 PM.

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90/30...more or less...

Last edited by ed good; 06/23/22 08:06 AM.

keep it simple and keep it safe...
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To comment on Stan’s post…..

Dewey is entitled to his opinion. He’s a very talented, extremely skilled individual, there’s no denying that. His opinions and views carry a lot of weight with people involved in our hobby, especially with individuals who are also interested and participate in the mechanical side of the hobby.
I’m too am entitled to my own opinion, an opinion that has been formed from years of my own personal experience in addition to watching, and LISTENING, to many other, equally talented, sometimes vastly more experienced gunmakers than Dewey, especially ones that have a “speciality like barrel making, stocking, etc.
I take it all into consideration, pick up on the things that make sense to me, ask a lot of questions, do a lot of thinking, contemplating and then form my very own, personalized opinion on the subject.

I emphatically disagree with his assessment on the use of mechanical gauges in regards to measuring wall thicknesses on barrels. In fact, I think it’s total bullshit. I’ve seen some of the very best in the business use mechanical gauges to great effect. And some of the finest guns in the world made today are still being made with the use of mechanical gauges just like the one I pictured earlier. There, that’s my opinion on it.😂.
Does that mean that I also disagree with his opinions on spring making, metal working, bad vs good gun designs, etc. Hell no. I agree with a lot of what Dewey has to say on a myriad of gun related subjects. I still wish he posted here and shared more of his experience and knowledge, but I fully understand why he boosted out of this place too.

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Originally Posted by Stanton Hillis
So, all of you who own mechanical wall thickness testing devices disagree with Dewey V. ?, who says:


Mechanical Wall Thickness Gauges Are Worthless

Traditional barrel wall thickness gauges are inherently inaccurate due to the flexibility of the barrel arbors. This includes the vaunted "English Gunmaker's Style" that uses three rods mounted in a baseplate. The reason is that the arbors are solid rods that can be 14 to 18 inches in length and no matter how stiff you might think they are, they absolutely are not. They will flex measurably at the slightest provocation. This tool serves little more purpose than to impress the ignorant onlooker. It is guesswork with a dial indicator, nothing more, and was never the best tool for the job, even though it was the best that could be hoped for at a certain time. Thankfully, that time is passed. The ONLY widely available method of absolutely accurate wall thickness measurement is through the use of ultrasonic measurement. The tool that I use is the DeFelsko UTG P1 which is capable of measurement down to .008" in steel with an accuracy of .0004" (four TEN thousandths of an inch). Yes, it's expensive because actual accuracy costs, but it's worth every penny.

Here is some proof of the flexibility of the "traditional" gauge construction. The following video shows just how much movement there is in a .625" diameter water-hardening steel rod, at 16 inches unsupported length, chucked in a 5C collet in the lathe. This setup is much more rigid than any baseplate mount. The amount of deflection (a lot) versus the force applied (very little) should illustrate why ten different people will get ten different readings of the same barrel.

"But it's used in a vertical position" you say. Think about the fact that half of the barrel length is above the uppermost end of the arbor and that the inner wall of the barrel being measured MUST contact the arbor. Do you really believe that you can hold the inner wall in contact with the arbor, while not inducing ANY side load and causing it to deflect at all?

"But it's better than nothing" you say. No, erroneous information is worth exactly nothing.

"But so-and-so uses it and always has" you say. Of course, it looks snazzy, it impresses those that don't know any better and it's cheap to make. As you'd expect, it is also monumentally overpriced to buy, which further cements its "credibility" with the purchaser.




Apparently, he has so much credibility on this board when he speaks of other doublegun related topics, why not this?

All measurements are erroneous. Every single one. So, trying to pare through the hyperbole to get meat of the matter, how does Dewey respond to those that claim to be able to repeatedly measure known thicknesses with satisfactory accuracy and precision? I build decks and barns with tape measures, though they are not nearly as precise or accurate as vernier scales and micrometers. The deck hasn't fallen down yet.

This seems like "my dog's better than your dog" sort of BS. Par for the course on doublegun.com, however.


_________
BrentD, (Professor - just for Stan)

[Linked Image from i.imgur.com]


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I didn't know about ultrasonic until lately. So I can't speak to it's accuracy. In a Double gun class I took 3 separate mechanical gauges with 3 people using them came within .001 of each other in measurement so it was repeatable. Does anyone have an idea what an ultrasonic device costs?

1 member likes this: Stanton Hillis
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