Thread: Enfield Barrel Drawings?
Retrieved: 06/06/2014

Would anyone know where to find a copy of the factory drawings for the SMLE No.1 barrel, as well as the "Heavy' version and also the No.4 barrel?

paulseamus
06-19-2013

Heavy barrels were made by Lithgow. Every few months or so an unfired heavt barrel goes on sale in Australia. Probably because a family are having a cleanout of an old target shooters safe.

keep an eye on usedguns.com.au last one sold in minutes for $425 Aus dollars.

Bruce_in_Oz
06-19-2013

Would anyone know where to find a copy of the factory drawings for the SMLE No.1 barrel, as well as the "Heavy' version and also the No.4 barrel?

Yep: Powerhouse Museum in Sydney: good luck!

That said, the basic profile of a SMLE barrel is pretty simple.

The "H" barrel is basically the profile of the earlier "long" Lee Enfield barrel grafted onto a standard SMLE Knox Form and with a short "step-down" at the muzzle to accept the standard SMLE front sight band and key.

The breech thread is an "Enfield Special". It is NEITHER Whitworth nor UN form, but its own special 49deg 40min form, with radiused roots and crests like a BA.

SMLEs (and Mauser 98s) breech on the INNER receiver ring, NOT the front face of the receiver. No.4s (and 5s), however, breech up on the front face of the receiver body.

Peter Laidler
06-19-2013

From the simple engineering point of view, surely a CNC shadowgraph trace is all that is required to make the external drawings and thereafter, the actual turning should be a doddle or am I missing something? It just seems as though this is being made to be something complicated when it's really not.

We already know that rifling and chambering is another matter but...

Paul S.
06-19-2013

CNC shadowgraph --- nice thinking Peter. Do a cast of the chamber and you'd be almost there.

I have to wonder if something like this gets inordinately complicated from an over-exposure to modern engineering geometric dimensioning and tolerancing methods.

enscien
06-20-2013

The drawing for the No.4 Rifle barrel, Mk.1 (5 groove rifling) DD(E) 450/3 should be available from the library at the Royal Armouries, Leeds.

tbonesmith
06-20-2013

FWIW I would not hesitate to contact Lithgow small arms factory museum in Lithgow Australia, and I would imagine that for a fair "donation", someone would look up the relevant drawing.

Just a thought...

Bruce_in_Oz
06-21-2013

There is an interesting story there.

The museum is a sort-of "private" operation, and has been for quite a while. It was effectively run by local volunteers and enthusiasts, even when it was "semi-government".

The paper archives used to be stored in the top rooms of towers in the original rifle factory buildings. Pretty much everything had been microfilmed and this was all supposed to be filed on "aperture cards" with the engineering department.

The quality of the micro-filming photography left something to be desired. The original tracings (both waxed linen and paper "vellum"), old-style blueprints, paper prints etc were filed in the towers, in large, heavy card sleeves, bound with the classic Red Tape (actually pink). The ENTIRE collection of Lysaght's Owen drawings were reported to be mouldering away in a heap beside an old cabinet in one of these towers.

On top of this, an unknown number of folk had visited the towers and "borrowed" stuff. A classic example is the UNIQUE coloured rendering of a Vickers with tripod and water can. The microfilm record had a picture of it, but, in the archive room, all that remained was a dodgy print FROM THE MICROFILM.

The Museum folk had acquired some of the stuff for SMLE and Bren, but the collection was FAR from complete or coherently catalogued or stored.

And then there was the old BREN building, the one seen to the left of the front gate at the time. This housed a room full of the ORIGINAL card-files in their antique wooden drawer cabinets. These included a reference to EVERY factory drawing dating back to the survey of the site, through the structural plans, the signs for the canteen and EVERYTHING that the factory made or even proposed, including fittings for RAAF aircraft, components for various railways, electric sheep-shearing equipment and most intriguingly, major components for several US manufacturers of small-bore rifles.

When our French cousins bought the entire ADI operation, they cleaned out EVERY facility in ALL the various plants.

The remains of the Lithgow document collection were "donated" to the Powerhouse Museum in Sydney.

Given the politics involved, it is unlikely that they have been archived and catalogued correctly. It is even LESS likely that anything remotely useful there will EVER see public light of day.

Paul S.
06-21-2013

You're not wrong there. There is probably a tonne of stuff there that hasn't been sorted through, classified, digitized and properly preserved and archived.

I tried doing an on-line search of the Powerhouse Museum for Pattern 1918 Telescopic Sight Drawings not once but several times, and got bugger all for the effort. On-line searching the National Archives yielded the same result. I'm thinking the only way to get any real research results is doing it the old-fashioned way - go there, sit for hours (or days) and manually search through the document collection.

ssj
06-21-2013

BTW, is the idea to have a "genuine new barrel" or simply a new barrel? Given how hard it is to get barrels I wonder if any are available from POF? otherwise you can get an aftermarket MAB barrel.

Nailcreek
06-21-2013

Thanks Gents for posting. I've sent a request to the Lithgow museum, but haven't heard back. While I understand that he could take the dimensions off the take-off barrel I supplied, my concern is that if he uses one barrel, well... you have the dimensions from one barrel. I've no idea how close the barrel is to the factory spec, hence my interest in getting drawings over to him. At least then, the barrel is almost "new old stock", so to speak.

Bruce_in_Oz
06-21-2013

If you are making a SMLE barrel, there are a couple of things to keep in mind:

The taper is straightforward; the challenge is turning and finishing a long, flexible tube without excessive vibration. The final finish was originally done by grinding.

The thread can be cut conventionally with a single-point tool, or you can go wild, grind a fancy milling cutter and do it in your trusty Bridgeport with the fancy gearbox gizmo attachment.

The thread IS qualified; HOWEVER, if you profile the exterior but ignore the "driving flat" on the Knox form, you can cut the thread by the technique of your choice.

The trick is to then machine the flat AFTER fitting, ditto the slot for the front sight block/band. That way it SHOULD all end up square.

As for fitting the rear sight base; even in the factory there appears to have been an "allowance" for "adjusting" the barrel exterior so that the sight base fitted without distorting the barrel or the base.

Because the factories had the tools AND gauges, they could supply barrels already fitted with front and rear sights as spares for armourers.

The location of the extractor slot and the feed ramp in the rear of the tenon can be marked out during "hand" fitting and then machined. Note that the extractor slot is radiused to match the form of the ectractor.

Remember that SMLEs breech up on the REAR of the tenon, not on the shoulder. The rear of the tenon is also the face from which headspace for the rimmed .303 is gauged.

Paul S.
06-21-2013

Originally Posted by Nailcreek
...he could take the dimensions off the take-off barrel I supplied, my concern is that if he uses one barrel, well... you have the dimensions from one barrel. I've no idea how close the barrel is to the factory spec, hence my interest in getting drawings over to him...

Bruce's reply above offers the best information from the machinist's perspective - and you have to love it when a true professional speaks.

Looking at your problem historically from a draughting perspective, current geometric dimensioning and tolerancing is a comparatively recent innovation. The first nationally coded draughting standard, BS308 didn't come into effect until 1927! From all evidence, early 20th century mass-production manufacturing depended very much upon either 'try and fit' or hand-fit. That meant you had a box full of parts 'A' and another box full of parts 'B', etc. You'd take a part 'A' and try parts 'B' until one fit. The odd bits were set aside and hand-fitted if need be. That said, using a new made component produced using nominal dimensions would be essentially what occurred at least until the middle of WWII.

Peter Laidler
06-22-2013

Bruce in Oz and Paul S hit the nail straight on the head... The No.4 AND the No.2 revolver were classic examples of what we call 'selective fitting' - as were Webley revolvers too. A good example was that some new No.4 barrels were extremely tight in the action you were re-barrelling and there was simply no chance of screwing it in by hand to start. On the other hand, some were so loose it was like throwing a sausage down the main street! And don't even get me started about fitting new factory toleranced parts into No.2 revolvers...

Bruce mentions the nocks form or breeching up flat against the indexed barrel thread. You should NEVER rely on this breeching up flat to align anything other than...., well, nothing! I have seen that flat used to align barrels using the gauge supplied (as opposed to the Armourers own gauges/flat plate) and the foresight block has been visibly canted over.......