What's the proper procedure to fit a bolt to a Lee enfield rifle? I checked mine and only one of the lugs is making contact. Wondering how I should proceed.
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What's the proper procedure to fit a bolt to a Lee enfield rifle? I checked mine and only one of the lugs is making contact. Wondering how I should proceed.
Sent from my MB870 using Tapatalk 2
Peter Laidler's list of on line articles is a sticky in this forum: Index of Peter Laidler's on-line series of articles.......
The article that will help you is: http://photos.imageevent.com/badgerd...0boltheads.pdf
Check out the rest of the articles and posts, it's GOLD!!
Maybe this link will do right?:
http://photos.imageevent.com/badgerd...0boltheads.pdf
ETA: Yup! Click above!
Lots of great information there. Are replacement bolts and bolt heads still available? Is it possible to stone to much material off the bolt and render it worthless? Or could you simply keep extending the bolt head within reason?
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Very possible to stone too much off. You don't have much room at all.
If we are talking about a N01 Mk111 type, several things must be borne in mind:
1. There was ONE and only ONE bolt head issued for that rifle until a tiny batch of "longer" boltheads were made at Lithgow post WW2.
2. If the receiver and bolt have the same number and these numbers appear original, you have a problem.
3. SMLEs were made from a variety of carbon steels; no fancy alloys like 8620 etc. Thus, each component had its own peculiar heat treatment to echievr the desired hardness, malleability etc. Essentially, the locking surfaces are case hardened. If you have a chance, take a close look at a prime, unrefurbished specimen of late Lithgow production. There you should, see a small area of discolouration and surface texture change on the exterior of the receiver immediately to the rear of the locking shoulders. This "defect" is where the carbon electrodes were applied to "spot-heat" the metal around the thrust-bearing shoulder as part of the heat-treating regime.
The hard "skin" on SMLE receiver locking shoulders is quite thin; ditto the bolt lugs. If you lap off more than a couple of thousandths from a component that has already been cycled a few million times, you will probably have little hardness left for correct operation.
4. Without a "master bolt" or factory gauges, establishing the exact staus of the bolt and receiver is very difficult, especially if you also do not have all of the original documents for data.
5. If the suspect" shoulder is the one on the right hand side, the gap can be measued with feeler gauges after you close the acton with the striker cocked and preferably with a DUMMY round in the chamber. This condition provides a reasonable emulation of the alignment of the components immediately before firing. If it is the LHS shoulder/lug, good luck.
6. The one glimmer of hope is that on the "non-contact" lug, the error MAY be only just greater than the thickness of the film of bearing blue. The trick is to establish just how much greater.
Bruce this is a NO4 MK1 i am dealing with. I need to put some blueing on and see what it looks like i have just been inking it up with a sharpie and seeing what gets scraped off may not be the most reliable method. I tried to get a .001 brass shim in the right side and could not get it in at all. I purchased this book The 2012 Complete Book on Lee Enfield Accurizing and have been going through some of the steps in it.
Here is a picture of the channel the left lug rides in. Does this look normal? Not sure if it is supposed to be relieved like that at the top. Maybe to allow the bolt to close if you happened to get some crud in there? Also on closer inspection some of the ink rubbed off on the left side on the receiver but did not scrape any off on the bolt itself. Going to actually blue it tomorrow and see what it looks like. I think it may not be as bad as I thought. I went into a panic there for a minute thinking it may be beyond repair.
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Enfield Fan:
Some consoling things about No4s:
Most of them are newer than most SMLEs
You can still find the various different-length bolt heads around the place.
However, whilst most dimensions are different, in varying degrees of subtlety, most of the gauging principles and even tolerance schedules of the No1Mk111 apply to the No4.
The LHS locking shoulder (resisting surface) was rough-cut using a semi-ball-nose end-mill cutter. That is the tool that left all those swirly marks in the shoulder recess. The final forming of the critical locking surface was done with a shaving tool. This is essentially a long-ish bar, of hardened tool steel, with a tiny cutter blade attached. It resembles a boring bar with the cutter bit halfway down its length. There was a jig that guided the final shaving tool. There was also a set of special gauges to check the work at each stage.
The trick was to cut the load-bearing surface at the correct helix angle AND in the correct place. Important point: because Lee Enfield locking surfaces are HELICAL, as are those on P-14 and M-17 rifles, it may be a bit injudicious to just go in with a Dremel or diamond file and grind away. On the “plus” side, you only need a contact area, at lockup, of about 2mm square, to keep it all together.
One thing to note is the tolerances on the relative positions of the gauging points on bolts and receivers. The ABSOLUTE position of the bolt lugs has a tolerance of 0.004”. The allowable DIFFERENCE in relative location of the lugs is0.001”. “Cutting it fine, so to speak.
On the receiver, the allowance on the mean location of the gauging point on the shoulders is 0.004”; the tolerance on shoulder RELATIVITY is 0.002”
But wait, there’s more!! I don’t know about the No4 process, but with SMLEs, the piece d resistance, so to speak, was that the initial chamber in the almost-finished but un-fitted barrel, was cut a bit small. There was a “special” proof cartridge used to proof-fire the barrel in a fixture and then, if it passed, it was finish-reamed and subjected to more operations and gauging.then assembled to the “not quite finished” bolt and receiver. This assembly was then “proved” again with a cartridge containing 33grains of No3 Cordite and a service bullet of 215 grains. This proof firing also “set” the locking surfaces.
Thank you lots of great information there!
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By the sound of it, you are probably better off using your existing bolt in that rifle, rather than start grinding away at some replacement and possibly ending up with a much worse situation.
I wonder whether "bolt fitting" might be an overheated topic? There are hundreds of thousands (millions?) of Enfields with mismatched bolts, and probably a large majority of those have never had the replacement bolt checked for fit. There are no observed major negative effects of a mismatched and unfitted bolt, given the huge numbers of rifles involved, so it may be that the system simply adapts to slight asymmetries in lug bearings. I.e. perhaps the bolt and receiver has sufficient inherent flex to absorb asymmetric forces, and perhaps the mismatch is eliminated fairly quickly over a few rounds in much the same way as happens when the rifle was originally built and proof-fired?
Just as long as the long lug is doing the load bearing, it may be OK. Kind of Krag-like. But the small lug may be too small to do all the work alone. See Posts #51 through at least #58 in the thread below:
Gallery of Dramas. Broken Enfield Parts!
Been a while since anyone has added to the gallery, but there's some interesting contributions by quite a few of the Milsurps gang.
ETA: Some more in Posts #65 and following.
What are the correct bolt to raceway tolerances for the Lithgow Smle?
What are the wear points in the raceway of the SMLE receiver caused by the bolts travel through it?
Whith light shining on the bolt head locating rib, there seems to be a change in the colour of the metal just back from the chamber face and between this point and the charger bridge. This change in surface colour, I assume is caused by wear as the bolt cycles along this track?
If this is correct. Then how can this be corrected or restored? Can electrolysis be done to add metal to this area and other wear points within the receiver, to bring the receiver back to factory fresh tolerances or better than factory?
What can be done to bring back the SMLE to as new again?
What is the differences in metallurgy between the Ishapure Smle and the British/Lithgow Smle? Why was the Ishapure stronger?
There is an article explaining this myth, but I can't find it for now.Quote:
Originally Posted by Hammer4
My understanding is that they were not any stronger, Ishapore just changed their proof test method so they passed.
Quote:
Originally Posted by Hammer4
I'm afraid you have been misled by 'internet facts'.
The truth is that the Ishapore No1 Mk3 is actually manufactured from inferior steel and rather than 'lose-face' and revert to the 'proper' steel grades they decided to alter the proof testing to get it to pass.
The 'full story' was published many years ago by the Ishapore Proof Master, but there are some forums and information sources that say he is wrong. (One of the main proponents of the 'false information' is a forum that supports the fact that the chambers of the No5 Mk1 rifle were made oval to allow the water from the tropical monsoons to drain down the barrel & out past the round)
The article covers a host of subjects (and several pages) based around the Indian firearms industry and more specifically the ‘Proof House’, but of particular interest are a couple of paragraphs regarding ‘Enfield’s’.
Extract from “Gun Digest 33rd Anniversary 1979 Deluxe Edition”
Article Author : Mr A G Harrison
Qualification : Former ‘Proof Master’ of the ‘Rifle Factory Proof House, Ishapore, India’
From 1908 to 1950 all military bolt action rifles made at Ishapore were proof tested with a dry-round, followed with by an oiled proof round (as per UK military requirements). The proof cartridge was loaded to 24 tons psi breech pressure, or 15% higher than the service pressure. In 1950 (after the departure, in 1947, of India from British control) the material for the rifle bodies was altered from an EN steel to SWES 48 steel with the recoil shoulder and cam recesses being heat treated. With this change the rifle receivers distorted when oiled proof cartridges were fired. This was discovered when hard and sometimes impossible bolt retraction was experienced. Large quantities of rifles were rejected.
To avoid rejections the authorities ordered discontinuance of the oiled proof round. Therefore from 1950 to the end of SMLE production, rifles made at Ishapore were proof tested with one dry proof only, although the specification still called for both dry and oiled proof. All bolts and bolt heads issued as spares were always proofed with a dry proof round only.
Although you asked about the 'SMLE' a little bit more infortion was provided by the Proof Master about the SMLE derivative - the Ishapore 2A & 2A1 which were built on the SMLE action.
They first manufactured the 2A using the same steel as they were (now) using for the No1 Mk3 and it was an unmitigated disater as it was unable to withstand the forces of the 7.62 round, and warped, twisted and totally 'locked up'. Ishapore then decided to (save face) and announce they were using a 'superior grade' of steel, when in fact, what they did was actually revert back to the original British specified EN steel for the 2A, although the manufacture of the No1 Mk3 retained the SWES steel and all the No1 Mk3s were tested under the new proofing regime.
Never believe anything you see on the internet unless it is supported by either period documentation, or written by those personally involved in the subject.