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no36 mills gas check question
- Thread starter Darrol
- Start date
Grenademan2005
Well-Known Member
Yes, I was going to write the same, market is full of fakes as original ones are not easy to find.
thanks guys .the two i have are original. . . the most recent being a good millimeter thinner . markings visible is an A next to the broard arrow on the screw side .its a little rough so other markings are very faint or half there .
i wondered if early ones were made of thinner plate .
thnks Darrol
i wondered if early ones were made of thinner plate .
thnks Darrol
hi .
can feel the difference between them both .the others quite thick in comparison .
ta .Darrol.
I agree with Snufkin . The thickness is not negotiable . They are identical in WW1 & WW2 as he has stated . They are pressure gas checks , not artistic add ons . They are made to EXACT tolerances . It would be like saying 9mm ammo could be anything between 8-10mm . It makes no sense . Dug ones may have slight differences due to corrosion but 1mm on unused ones is NOT possible . Hope this helps.
hi .the used one is 3mm thick (measured at the cleanest unrusted part) and the unused one is 4mm .
i do know they are genuine .but i doubt
it would loose a mill in thickness due to launching .
regards Darrol.
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The first post asked whether WWI and WWII gas checks were of different thicknesses. The answer is no. Inspection drawing IDW B/254 of 1917 specified 9 SWG plate steel for the gas check, and this remained good until post-WWII.
Variation in thickness of gas checks (from the same conflict, WWII) seems to have become the issue of interest. Accepting that fakes are not in the mix, this is down to manufacturing tolerance of plate steel.
Modern plate steel is produced in a number of grades, and current European standards specify different tolerances on nominal thickness. For plate between 3 and 5mm thickness (including, for example, 9 SWG at 3.658mm):
Class A, Lower -0.4mm, Upper +0.8mm
Class B, Lower -0.3mm, Upper +0.9mm
Class C, Lower 0mm, Upper +1.2mm
Class D, Lower -0.6mm, Upper +0.6mm
I am not aware of the standards for plate manufacture in either WWI or WWII, but I would venture similar gradings were applicable. Manufacturers of gas checks would be supplied with lots from the steel mills, so gas checks from a particular batch should be of similar thickness, but from batch to batch the thickness could vary.
Tom.
Variation in thickness of gas checks (from the same conflict, WWII) seems to have become the issue of interest. Accepting that fakes are not in the mix, this is down to manufacturing tolerance of plate steel.
Modern plate steel is produced in a number of grades, and current European standards specify different tolerances on nominal thickness. For plate between 3 and 5mm thickness (including, for example, 9 SWG at 3.658mm):
Class A, Lower -0.4mm, Upper +0.8mm
Class B, Lower -0.3mm, Upper +0.9mm
Class C, Lower 0mm, Upper +1.2mm
Class D, Lower -0.6mm, Upper +0.6mm
I am not aware of the standards for plate manufacture in either WWI or WWII, but I would venture similar gradings were applicable. Manufacturers of gas checks would be supplied with lots from the steel mills, so gas checks from a particular batch should be of similar thickness, but from batch to batch the thickness could vary.
Tom.
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Hi. Unfortunately I do not have enough WW1 Gas Checks to form an opinion on their average thickness (donations welcome). However, I do have sufficient WW2 era ones to make an informed comment on their gauge.
Understanding the variation commonly found in WW2 made gas checks will help establish a base line from which the potential variation of WW1 and WW2 discs can be determined. If this is not done, what are you calling a WW2 gas check? Ive only measured about 30 WW2 discs this evening, so these results are by no means definitive. The range in variation was 3.26mm 3.89mm (i.e. ~19.5%) with a mean of 3.72mm. When handling the two gas checks at each extreme the physical difference in their weight is very noticeable. It would be interesting to hear the thicknesses of WW1 gas checks, from those who have multiple examples in their collections. Cheers
Understanding the variation commonly found in WW2 made gas checks will help establish a base line from which the potential variation of WW1 and WW2 discs can be determined. If this is not done, what are you calling a WW2 gas check? Ive only measured about 30 WW2 discs this evening, so these results are by no means definitive. The range in variation was 3.26mm 3.89mm (i.e. ~19.5%) with a mean of 3.72mm. When handling the two gas checks at each extreme the physical difference in their weight is very noticeable. It would be interesting to hear the thicknesses of WW1 gas checks, from those who have multiple examples in their collections. Cheers
Attachments
Hi. Heres an interesting part of the jigsaw (Precision Engineering = NPZ). Cheers
http://paperspast.natlib.govt.nz/cg...=79&e=-------100--1----0grenade+manufacture--
http://paperspast.natlib.govt.nz/cg...=79&e=-------100--1----0grenade+manufacture--
I've got a nice 1918 dated one here that is 3mm. 3 Battlefield recovered examples (pitted) that still come in at 3mm and one battlefield recoved example that is about 3.25mm, which I take to be a manufacturing anomaly. Sizes are ruler checked so not scientific. John
Oh, I've just checked some repro gaschecks I have in my shop and they are thicker and more like 4mm. These are plain, no markings at all. I think the repros Dug Up sold had a broad arrow on them.
John
Oh, I've just checked some repro gaschecks I have in my shop and they are thicker and more like 4mm. These are plain, no markings at all. I think the repros Dug Up sold had a broad arrow on them.
John
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