Reply With QuoteI love it. Looking forward to the updates...
Airgun Alchemist, Collector and Scribe
One of my quirky interests lies in patented spring air pistol designs that never went into production, and it has been great fun making working examples of these and seeing how they perform. At the same time this has taught me how to use a lathe, as well as some of the basics of gunsmithing. After my last project, the next one on my bucket list was a pistol design patented by Lincoln Jeffries Jr. in 1926. This describes a fixed barrel overlever pistol in which the piston moves rearwards, as in the Webley pistols. (British patent No. 254,640. 1926)
I can only assume that LJ’s motivation behind this design was to overcome the criticism of the Webley pistols that their barrel cocking system could lead to bent barrels. At first sight the patent seems obvious, and just involves the addition of an overlever cocking arm to the basic Webley design. However, when you think about it, no overlever pistol had ever been described before and so it was an original concept. Furthermore it obviously did have commercial potential, as LJ’s overlever system was many years later copied and marketed successfully in the Weihrauch HW45 and the BSA Magnum 240. Possibly with aggressive marketing, Lincoln Jeffries Jr. could have made a dent in the dominance of the Webley air pistols with his design, but for whatever reasons he never brought it into production and any workshop prototypes will be long gone. I thought that a reproduction of this pistol would make a nice addition to my collection.
Usually I post my projects when they are completed, but I thought this time I would put my neck on the line and map out the project as it progresses, problems and all. Hopefully it won’t stall and there will be a finishing line, but you can’t always tell with these things. There is always the possibility of meeting a machining challenge that you can’t overcome with amateur equipment and so the project could be permanently shelved. I do not work to a schedule and tend to dip into my projects as and when the mood takes me, so getting to the final product could be a long haul, or might only take a couple of months. I have already made a start, and this is a summary of the results so far. I will add further posts as things (hopefully) progress.
The drawings were studied and a build strategy mapped out, and then the drawings were scaled and the various dimensions calculated. As always, the build starts with the carcase and everything else is constructed around that. The patent shows the carcase (cylinder, grip, muzzle and breech barrel housings) to be constructed as a single unit, presumably forged from steel and then milled and bored, but this was not feasible for me, and so the carcase was broken down into four more manageable parts as shown in the diagram.
The components were the cylinder (1), the grip frame (2), the breech barrel housing (3), and the muzzle housing (4). The intention was then to make these individually and then braze them together as invisibly as possible to give a single unit.
The cylinder (1) was made from a section of 1 inch OD precision seamless steel tubing, with a wall thickness of 2mm. This was first threaded at each end to receive the muzzle and breech plugs (the patent drawings show that the cylinder is designed to be accessed from both ends). The two plugs were turned down from round steel bar and threaded. The various steps are shown in the following sequence of pictures.
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The grip frame (2) was made from steel plate as shown in the next series of images. It was first roughed out with a hacksaw [pics (a) and (b)]. As it was eventually going to be brazed to the cylinder it needed to have a half inch radius concave profile along the top edge so that it would fit as closely as possible against the cylinder wall and give the strongest possible bond. Luckily I was able to buy a reconditioned half- inch radius ball nose end mill off the internet at an affordable price, and this was used to mill the necessary curvature, which you can make out in (c).
The grip was then skeletonised, as shown in (e). The last picture (f) shows the finalised grip frame with holes drilled in it and threaded to receive the eventual grip plate screws. Here it has been placed against the cylinder before it has been brazed into position, and the two cylinder end plugs are also loosely in position. This is that stage of a build project that I particularly look forward to, as it is now starting to look like a gun and this gives you a lot more impetus to carry on and complete the project.
I find brazing one of the most challenging aspects of gunsmithing, and when it comes to building guns I have found most of what is there in books and on the internet not particularly helpful for the amateur. Everyone seems to say that capillary brazing is the only way to go, but trying to do this at a temperature of 800oC while holding two relatively large components in precise alignment is all but impossible without very fancy equipment or a huge amount of practical experience. It is not the same as soldering, where the temperatures are only around 300 oC and you can use a soldering iron. Also when capillary brazing a large area joint you can’t be sure that the brazing metal has penetrated the whole area. I have done a lot of experimentation and have found out the hard way what can and can’t be done so I now use a kind of sweating technique of my own, which requires more preparation of the clamping system in advance, but does seem to give consistent results and good strong joints. As no two jobs are exactly the same a lot of thinking has to go into how the parts can be held together accurately while they are being held at a red heat. This Lincoln Jeffries pistol is going to involve me in five separate brazing steps, all with different problems to overcome.
Brazing the grip frame to the cylinder had special problems of its own, because of the awkward shape of the two halves for holding, and because the size of the two halves made heating the joint with a blowtorch to a red heat impractical due to heat conduction. So it was decided to heat the whole thing in a mini-furnace. To prevent lateral movement of the two parts during heating holes were drilled through the frame into the cylinder and two loosely fitting locating pins fitted as shown in this picture.
The pins were trimmed down. A layer of flux and a section of thin silver solder foil were sandwiched in the joint, and the gun was then held unclamped in a specially made frame as shown in the next picture. The whole assembly was then placed in the mini-furnace and heated to 800 oC until the brazing solder had completely melted and filled the joint. The weight of the cylinder bearing down on the grip forced out excess silver solder and ensured a very close contact between the two parts, so that the brassy yellow brazing layer was virtually undetectable after cleaning up the joint. The pins could then be filed down until they were invisible.
Making the barrel was in comparison very straightforward, and involved turning down an old rifle barrel to the right diameter and then threading the breech end.
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The next stage was to make the muzzle and breech barrel housing blocks (3) and (4). A steel block of the correct width and height was drilled with a barrel pilot hole and was milled along one side with a ½ inch radius concavity so that it fitted snuggly against the cylinder. The block was then sliced into two pieces to give simultaneously the muzzle block and breech block with their barrel pilot holes in exact alignment.
The hole in the muzzle block was enlarged to give a sliding fit over the barrel, and the hole in the breech block was threaded to accept the threaded end of the barrel.
The next picture shows the two blocks fitted to the barrel after they have received some additional shaping. Note that the breech block end face is angled so that it will mate precisely with the overlever breech closure when it is eventually made.
Finally the two blocks had to be brazed to the cylinder in two separate operations. Locating pins were used much as for the brazing the grip frame to ensure precise positioning of the blocks, but in this case brazing was carried out in the vise using a MAPP gas blowtorch as the heat source. This was quite tricky, as perfect alignment of the two blocks was critical, but thanks to the locating pins the outcome was OK. Here you can see the locating pin on the muzzle block.
When the two blocks were brazed in place, a check was made to ensure that the barrel could be inserted smoothly through the muzzle block and screwed tightly into the breech block. This shows the final result:
So having got the basic carcase of the gun sorted out, the next stage will be to make the cocking overlever, with its pivot pin, long links and barrel slider. The lever itself promises to be particularly difficult as it will be made up from four components involving two more brazing steps, where precise alignment of the various components will again be critical. I will be reporting on the outcome of this next phase, good or bad, in my next post, and with any luck even more progress - so watch this space!
Last edited by ccdjg; 31-05-2018 at 01:48 PM.
Registered User
I love it. Looking forward to the updates...
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
The collector formerly known as micky
Great project,look forward to seeing it finished and the proformance.
Registered User
Fascinating. Thank you for sharing with us.
Award-winning Airgun Anorak
Extraordinary work, John!
Interesting pistol. I suppose using the barrel as the cocking lever would have made it too like the Webley, hence the overlever? Yet again it underlines the genius of the Webley design...
Vintage Airguns Gallery
..Above link posted with permission from Gareth W-B
In British slang an anorak is a person who has a very strong interest in niche subjects.
Registered User
Oh wow! I thought you had been a bit quiet of late!
The Bulletproof Monk
I am really sorry I promised to send you some barrel stock, if you are coming to kempton I can bring you a selection....
A man can always use more alcohol, tobacco and firearms.
Airgun Alchemist, Collector and Scribe
No probs Richard, I managed to get what I needed from Vic at Protek. I would love to go to Kempton some time, but the prospect of a 400 mile round trip in one day and a dodgy back keeps putting me off. Some day it will happen!Originally Posted by RichardH
Cheers
John
Registered User
Awesome work, please keep us updated with the progress and lots of pics
NIge
Steyr LP10, Steyr LP5,
Vintage Collection - Walther LP53, HW77k Venom, BSF S20 Match, Original 35, ASI Target plus lots more
Registered User
Hello John,
Another fascinating project which will no doubt be followed closely by all admirers of your ingenuity and engineering skills in producing these prototype and experimental air pistols. The only problem is that it means we will have to wait even longer for an updated Encyclopedia of Spring Air Pistols or indeed a new book dedicated to air pistols that didn't make it into full production and the making of your superb reproductions.
Regards
Brian
The Bulletproof Monk
I have a stack of scrap barrels in .25, .22 or .177, mail me what you need and I'll send some up then, can even chop and blue them if it helps?
Kempton is a great day out, train maybe?
A man can always use more alcohol, tobacco and firearms.
Airgun Alchemist, Collector and Scribe
Thanks for your kind offer Richard. I have sent you a PM. Interesting suggestion about trains, I will look into it.
Cheers, John
Where's his User name?
Following
Donald
Registered User
not into old springers but nice work
Registered User
Well that puts everything I have ever made to shame, love the idea of making something that never was!
The trigger release looks to be a interesting part to get "just right"
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