Inspectors Bolt Gauge for ShtLE
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Topic: Inspectors Bolt Gauge for ShtLE
Posted By: WilliamS
Subject: Inspectors Bolt Gauge for ShtLE
Date Posted: April 10 2020 at 8:59pm
| Not sure where I'd find one or what a fair price is, but I have two No1 actions without bolts now and I'd like to verify their serviceability before fitting bolts to them. I have one NOS replacement bolt that I want to ensure goes into an action with a lot of life left. So, does anyone have one, or know what I should be paying if I find one? |
Replies:
Posted By: Shamu
Date Posted: April 11 2020 at 7:04am
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For the bolt or for the gauge? ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: WilliamS
Date Posted: April 11 2020 at 9:06am
The gage itself, I got the unissued bolt for $25.
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Shamu wrote:Posted By: Shamu
Date Posted: April 11 2020 at 9:23am
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Contact member Goosic on here, he's making some. " https://enfield-rifles.com/no-go-gauge-production-update_topic10484.html" rel="nofollow - https://enfield-rifles.com/no-go-gauge-production-update_topic10484.html" ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: WilliamS
Date Posted: April 11 2020 at 9:36am
Sorry I should have been clearer. Not a headspace gauge, but the Bolt, Inspectors Gauge that resembles a bolt but is much harder and ground to dimension, used for checking the receiver. I have a set of headspace gauges, and I've fit bolt heads before, I just want to verify the shoulders in the receiver are still in good shape.
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Posted By: Goosic
Date Posted: April 11 2020 at 9:47am
| The British Amorer's Gauge SM418 can be purchased from apexgunparts.com |
Posted By: englishman_ca
Date Posted: April 11 2020 at 10:12am
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Doh!! These are quite rare and are hard to find, I've been looking. And there they are on a web site! yay!! I got excited, I want one! Apex does not ship to Canada. Period.  It is a gauge not a gun part! WTF?Same story with many other US business vendors, Canada is a no go. Consequently, these days I seem to be buying most of my parts for projects from Australia and New Zealand. It can take a while, but they eventually appear in my mailbox, no problems. I am not familier with USA import regs, but ask, do US members have problems importing their bits and pieces from other countries at all? ------------- . . Look to your front, mark your target when it comes! |
Posted By: WilliamS
Date Posted: April 11 2020 at 10:18am
Thank you! I was just putting together an order of small parts with them, I didn't realize they had a tools section. That order just got quite a bit bigger.
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Posted By: WilliamS
Date Posted: April 11 2020 at 11:30am
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https://www.milsurps.com/showthread.php?t=31315" rel="nofollow - https://www.milsurps.com/showthread.php?t=31315 This is the gauge I am looking for. Re-reading that thread though it may be near-impossible to locate.
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Posted By: Shamu
Date Posted: April 11 2020 at 2:10pm
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OK now I unnerstann, thanks. You could actually fabricate one if you had to. I won't be easy though. Luckily there are (somewhat) easier ways. Get a decent bolt. Get several bolt heads of differing lengths. (easier said then done with a No1). Now make a "dummy case" (you need that to put rearward pressure on the bolt lugs) any fired MIlSurp case with the right rim dimensions should fit. Resize the case, remove the Decapping pin if you have a real boxer-primed case. Now you just made the gauge! It checks for headspace (hence the bolt/head setup) It checks even lug engagement (use dychem or magic marker) OR you can go to the several threads we've posted about bolt fitting. (Not trying to be snippy, sorry, but there are other ways than geting rare gauges). ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: englishman_ca
Date Posted: April 11 2020 at 2:15pm
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Man, you gotta love the internet and networking for finding credible info!!! What I have determined with help from some others over on Milsurps forum (lots of book worms over there with the manuals), is that those 'bolt gauges' that Apex is listing are for checking the lead and small cone, not for checking the bolt way or resisting shoulders. Apparently 'master bolt gauges' were few in number even when they were in use. Only used by a Master Armourer. Probably the closest to a gauge bolt that you could find would be an unissued new old stock unit. Of course, no where near as accurate dimensions as a gauge bolt, but at least one knows that it is made within tolerance and is unworn. Apex has em too. Apex has lots of interesting tools and gauges listed. Well worth checking out. ------------- . . Look to your front, mark your target when it comes! |
Posted By: WilliamS
Date Posted: April 11 2020 at 2:34pm
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Shamu, No problem! For being a younger fellow I can be real dumb with computers sometimes. Using the search function should have been my first stop. It looks like the best thing to do then is going to be to take the unissued bolt i just got, and make a set of dummy bolt heads for it at different lengths, since they don't need extractors or firing pin holes or anything. The only special tool I'll need to make for that is an Enfield thread form bit.
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Posted By: Shamu
Date Posted: April 11 2020 at 2:41pm
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There's an even easier way. Measure your bolt head. Find a longer one. (or attach layers of metallic tape to a "standard case" you have) all it has to do is put rear thrust on the locking lugs! Now mark the rear faces with Dychem or felt marker. Make changes to the locking lug rear faces til they're even (not "full" just even) there are several threads here mostly from "ZED" IIRC. NOW headspace the correctly fitted bolt, adjust the striker protrusion & BINGO! Done! ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: Goosic
Date Posted: April 11 2020 at 2:42pm
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Not to sound to dumb myself but, why an Enfield thread form bit? Do you happen to know what a Rube Goldberg machine is?
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Posted By: Shamu
Date Posted: April 11 2020 at 2:48pm
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Its not as daft as it sounds. The old SMLE bolts weren't just an odd TPI but a strange thread profile too. It was way more specialized & non standard back then, they even had an "Enfield Inch"! I have an old OLD "Engineers Notebook" from the 1890's there were thread forms (in the same size & pitch) with different profiles! It was a gift from my old boss who was an old time engineer. It was for things like self-locking & free running applications. ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: WilliamS
Date Posted: April 11 2020 at 3:01pm
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Shamu got it in one, there's all sorts of odd thread profiles and pitches left over from pre-standardization. Not an issue if you are starting from scratch, or on newer firearms, but it can get weird the older you go. The bolt head at least is 20tpi so don't need to do funny things to the lathe to run it. It does seem like I'm overcomplicating things for myself, probably best just to fit the bolt and not fret so much.
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Posted By: englishman_ca
Date Posted: April 11 2020 at 3:41pm
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Remember, the old non standard engineering specs were a standard at one time, for somebody. At the time that Enfield was getting into tooling for mass production (circa 1856) and needed standardisation, there was no universal standard of measurement so they stuck a stick in the sand and established their own. The Imperial inch standard came later. A difference of 0.0004 inches, I believe. It caused all kinds of initial problems with tolerance stacking for Lithgow. Some of the strange thread pitches might seem bizzare to some these days. Why a thread pitch of 26-1/3 per inch?? Simple answer actually, the change gears for thread cutting on the lathes just worked out that way and was actually an easy gear change to do on that equipment. Most modern machinery does not have these screw cutting gear ratios and combinations, they have different sized gears. The Enfield thread form is a little different in angle and has rounded crests and valleys. But cutting tools can be made, little problem. Enfield thread forms work well and are robust. So back in 1856 a screw 0.181 inch in diameter and 26-1/3 thread pitch was straight forward to make, where as a modern common Unified threaded screw might have been a challenge with special tooling needed. One thing that I don't have is a set of Enfield thread taps and dies. If somebody ever had some made, I am sure that they would sell well. ------------- . . Look to your front, mark your target when it comes! |
Posted By: pisco
Date Posted: May 12 2020 at 2:24am
| a set of taps and dies would be handy |
Posted By: Zed
Date Posted: May 12 2020 at 11:44am
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When I replaced the bolt body for the No1MkIII*. The new bolt body was 0.006" six thousandths of an inch longer than the original when fitted. Measured with the same bolt head. Head space was on the field gauge limit (0.074") with the original bolt and now is around 0.068". However to fit the new bolt, it required very careful stoning on one lug to get equal contact on both. I used jeweller's Arkansas stone to adjust the lug. Probably only 1 or 2 thou removed to get the fit. If you want to use the new bolt as a test; test the lug contact when you check the headspace. You may need a few thou' of that head space to get the lug fit adjusted. ------------- It's nice to be important, but it's more important to be nice! |
Posted By: Shamu
Date Posted: May 12 2020 at 1:27pm
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Weren't most of them BA? Check out Brit old car collectors sites they used BA a lot IIRC. MG comes to mind specifically. These guys in Oz? https://www.lprtoolmakers.com.au/ba/" rel="nofollow - https://www.lprtoolmakers.com.au/ba/
------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: The Armourer
Date Posted: May 12 2020 at 2:40pm
The number 4 rifles were (primarily) BA threads but the No1 MK3 were weird Enfield inch 'specials' Example - Ejector screw on the No4 is 3BA, whilst on the No1 Mk3 it is 0.1656" x 37 TPI |