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Joined: May 2011
Posts: 1,145 Likes: 37
Sidelock
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OP
Sidelock
Joined: May 2011
Posts: 1,145 Likes: 37 |
I'm in ther market to buy a barrel wall thickness gauge and came across these on ebay. A shotgun forum in the UK highly recommends them but what are your thoughts? Do the ultrasonic barrel wall thickness gauges work on our shotguns? http://www.ebay.com/itm/GM100-Ultrasonic...igital-Testing/
Nothing is foolproof to a sufficiently talented fool.
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Joined: Dec 2001
Posts: 3,964 Likes: 89
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 3,964 Likes: 89 |
Looks like the item has been removed from ebay.
When an old man dies a library burns to the ground. (Old African proverb)
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Joined: Jan 2006
Posts: 9,433 Likes: 316
Sidelock
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Sidelock
Joined: Jan 2006
Posts: 9,433 Likes: 316 |
I can't comment on the ebay item, but a mechanical engineer friend who is also investigating NDT of pattern welded barrels found that the $1900 TI-007 Precision ultrasonic wall thickness gauge has a measurable range from .006" to 1" with a resolution of .001". However the manual states that the minimum radius for convex surfaces measured is .5" or a little larger than a 4 bore, or 2.5" for a concave surface.
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Joined: May 2014
Posts: 90
Sidelock
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Sidelock
Joined: May 2014
Posts: 90 |
Yes, ultrasonic units are great, but even the tightest radial transducer needs an OD greater than our shotgun barrels... Sorry.
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Joined: May 2011
Posts: 1,145 Likes: 37
Sidelock
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OP
Sidelock
Joined: May 2011
Posts: 1,145 Likes: 37 |
I've been doing some of my own research and here is what I know. First you would most probably require a dual transducer of over 5 megahertz....about twice the price of a single transducer. The radius of our shotgun barrels does present a problem with the ultrasonic wave dispersion however that can be somewhat overcome if using a microscopic probe. With a microscopic probe the surface needs to be smooth. Questions of pits on the inside and anything on the outside I.e. Etching on a Damascus barrel, rust, dents are just that questions. Until testing occurs the answer is unknown. There is a shotgun forum in the UK that has some experience and recommends them. Price of the one recommended by Dakota instruments $2000.
Nothing is foolproof to a sufficiently talented fool.
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Joined: May 2011
Posts: 1,145 Likes: 37
Sidelock
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OP
Sidelock
Joined: May 2011
Posts: 1,145 Likes: 37 |
That's the idea but low quality and most likely would not work. See above comments.
Nothing is foolproof to a sufficiently talented fool.
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Joined: Sep 2014
Posts: 96
Sidelock
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Sidelock
Joined: Sep 2014
Posts: 96 |
If you go on Ebay and search for the GM100 ultrasonic you will find about 20 listed from $65 to $165 buy it now price.
The difference in price looks to be the type of box it come's in.
They are all made in China and ship directly from China or
Hong kong.
Me personally, I don't think I would have much confidence in this unit.
In the specs it lists:
When the given thickness over 20mm, the accuracy is ±1%; when the given thickness less than 20mm, the accuracy is ±5%
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Joined: Mar 2002
Posts: 1,815 Likes: 4
Sidelock
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Sidelock
Joined: Mar 2002
Posts: 1,815 Likes: 4 |
This is a low tech solution to a wall thickness gauge that a friend of mine and I built. It works well. [img:left]  [/img] [img:left]  [/img] [img:left]  [/img]
Last edited by Stallones; 03/06/15 01:24 PM.
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Joined: Sep 2014
Posts: 96
Sidelock
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Sidelock
Joined: Sep 2014
Posts: 96 |
Stallones, Nice gauge...but the coffee table it is sitting on is just as nice
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