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Most Online1,258 Mar 29th, 2024
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Joined: Jan 2002
Posts: 9,739 Likes: 97
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 9,739 Likes: 97 |
doc drew, luv dat skimmer...
hit goes wid duh song an duh dance...
and to paraphrase wc fields...
if you cant impress erm wid facts, den dazzle erm wid bull shit...
an does awl dis barrel wall thickness measuring really have any practical value?
used to think so, but now ah wonder?
keep it simple and keep it safe...
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Joined: Dec 2001
Posts: 6,266 Likes: 199
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 6,266 Likes: 199 |
I have both the vertical gauge and the horizontal gauge. The vertical gauge is inherently not as accurate since one has to deal with the torque generated by the barrel not being measured. Even from a pulley hung in the ceiling the vertical measured barrel is subjected to the torque of the barrel to its side. The often seen brass “rest” on the vertical machines is just “for show” and the seller can manipulate the readings in front of the buyer. The horizontal machine uses only gravity , which is a constant, to generate good readings. I lost a fine gun, sold to a friend , that I thought had thin barrels as measured with my vertical machine. His gunsmith remeasured the wall thickness with a horizontal machine and the barrels were well within the tolerance I would have accepted if I had only known. My vertical machine sits near the furnace, while the horizontal machine is on the workbench.
When using the horizontal machine by myself, I let a half filled bag of shot hold the barrels on the bench. It is easy to turn the barrels, held by the bag of shot, to any position.
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1 member likes this:
Drew Hause |
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Joined: Mar 2002
Posts: 2,857 Likes: 384
Sidelock
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Sidelock
Joined: Mar 2002
Posts: 2,857 Likes: 384 |
I use the Manson gauge vertically,I have a spring on the arm that applies pressure to the ball machined on the end of the arm it works great .i can move the arm to 9.250 inches to eliminate some deflection
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Joined: Jan 2002
Posts: 9,739 Likes: 97
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 9,739 Likes: 97 |
daryl, you mention you have an acceptable tolerance,,,what would that be?
keep it simple and keep it safe...
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Joined: Dec 2001
Posts: 6,266 Likes: 199
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 6,266 Likes: 199 |
For that gun with Krupp barrels, I would have kept it if the mwt was over .020" at the proper point.
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Joined: Feb 2006
Posts: 137 Likes: 24
Sidelock
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Sidelock
Joined: Feb 2006
Posts: 137 Likes: 24 |
I have used Murph's "Hosford" horizontal technique with my Manson gauge for 10 years now and find it consistently repeatable within one or two thousandths. While experimenting with other ways to hold the block end, I realized that the cord in the eyebolt lets gravity do all the pulling and that the sensor ball naturally rolls to the bottom of the barrel without any side pressure influences from fixed holds on the block end. Thanks again Murph for saving me the cost of having to buy a Hosford tool, or one of Dewey's digital ultrasounds . MP
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Joined: Dec 2001
Posts: 3,962 Likes: 89
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 3,962 Likes: 89 |
I measure horizontally and to hold the barrels I clamp a sawed off section of a broom handle tapered slightly at the end to jam into the chamber of one barrel. Firmly prevents barrel from turning until I want it to.
When an old man dies a library burns to the ground. (Old African proverb)
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Joined: Jan 2002
Posts: 9,739 Likes: 97
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 9,739 Likes: 97 |
so what about this barrel wall thickness thingie...
does any of it mean anything re shooter safety...
or is it just a bunch of meaningless mumbo jumbo...
no one else here seems to want to suggest any guidelines for what measurements are safe...
watts up wid dat?
Last edited by ed good; 06/09/22 06:25 PM.
keep it simple and keep it safe...
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Joined: Jan 2013
Posts: 1,122 Likes: 192
Sidelock
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Sidelock
Joined: Jan 2013
Posts: 1,122 Likes: 192 |
I did find this interesting reading especially in the way things have changed when I was purchasing guns here in the past. Especially if you did what I did was to purchase guns at local auctions with the best guns always being a farm auctions, these nearly always had the lowest prices though with the largest risk of coming away with a bad purchase. It was always caveat Emptor with no returns. Now a lot of guns where as you could say especially polished up for the event with barrels well reamed and polished for the occasion so you had to be able to spot them easily. My main interest was 12 bore because this was the most popular gauge here because smaller bores the cartridge where more expensive and not popular with the only exception was the .410. Now I am sure you all know that a tenth of an inch on this side of the pond can turn a gun from desireable to junk instantly. So to put the odds in my favour I would have two Gauge's that I built on the kitchen table one was a go no go bore Gauge with two interchangeable inserts .729 inch the standard 12 bore barrel diameter and the other .740 inch the end of the line for a 12 bore barrel having a 9 inch stop. The other Gauge was a short light pocket version of a standard barrel wall thickness gauge that was also set to 9 inches, this 9 inch distance from the breech is where the guns bore is measured also the wall thickness and to be sure measure the barrel thickness 9 inches from the muzzle. So if the .740 inch went into to the bore 9 inches though I have had it go in the bore to the handle the gun was out of proof though all was not lost if the barrel wall thickness was over thirty thousands of an inch there was a good chance of re proof but only if there was enough thickness at 9 inches from the muzzle say twenty five thousands. Though you did have to use your judgment of how much metal would be left after all the pitting if any was removed, so the gun did have to be a top maker in good condition to take a risk. The other rod for the wall thickness gauge was for .410 though hardly ever used the two Tdi's one Metric and the other Imperial. Though now all this is now done for you because last time I went to a sales show there where Gauges on every sellers table
The only lessons in my life I truly did learn from where the ones I paid for!
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3 members like this:
WRE1, graybeardtmm3, Drew Hause |
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Joined: Jan 2002
Posts: 9,739 Likes: 97
Sidelock
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Sidelock
Joined: Jan 2002
Posts: 9,739 Likes: 97 |
dam, your go, no go gauge idea makes sense, if dealing with uk made guns only...over here we have guns made all over the world, with many different standards...do you have a standard for minimum wall thickness in front of chambers?
keep it simple and keep it safe...
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