Lincoln Jeffries pistol project Part 3. - Finished at last!

[ccdjg]

In part 2 of this quest to make a reproduction of the 1926 Lincoln Jeffries overlever pistol I rounded off by saying that only the piston, trigger, trigger guard and grips remained to be made. Fortunately Lady Luck smiled on me and everything went relatively smoothly and I am happy to say the gun is now finished in its entirety. Here are some pictures.








For those of you interested in how I tackled the final stages of the project, here are some details of how things progressed.

The first sequence of pictures shows how the piston was made. I could have made it from a long section of solid steel rod by turning it down and boring out the interior, but it was much easier to make it from steel tubing. First the piston head was made by turning down a short section of solid steel rod, as in pics (1) and (2). It was made so that it would fit tightly into a section of thick walled steel tubing that would make up the body of the piston. The tubing was turned down to give it the correct profile and diameter as shown in pic (3). After cutting off surplus tubing the piston head was inserted into the tube and brazed in place. The piston head face was then drilled, tapped and countersunk to accept a 3BA screw, as shown in Pic (4). A two piece leather piston seal (Pic 5) was made using a former to shape the cup washer. The completed piston with its seal, which was a snug but smoothly moving fit in the cylinder, is shown in pic (6).






The trigger system depicted in the patent is a simple one- piece unit. The trigger was roughed out from 5mm carbon steel plate with a hacksaw and filed to shape (pic 7) . It was drilled with a pivot hole and also a hole to receive a small spring (pic 8). The sear was carefully angled and polished to give as smooth a let-off as possible (not easy with this sort of one-piece trigger), and it was finally hardened by heat treatment. Pic (9) shows the trigger in place in the grip frame.




The next item on the to-do list was the trigger guard. This, according to the patent drawings, had a relatively thick curved cross section and was attached to the underside of the cylinder and grip edge with two machine screws through shaped ends . This meant that it had to be cut out from 5mm thick steel sheet, rather than fabricated by simply bending steel strip. The procedure is summarised in the next picture sequence.

After marking out the rough shape on a piece of 5mm thick steel sheet, the concave part was removed by a combination of drilling, hacksawing and filing, as in pic (10). One edge of the metal had to be milled to a half inch concave profile, as shown in pic (11), so that it would fit tightly against the curved cylinder surface, and this was done with a ball-nosed end mill. The outer curve of the trigger guard was then cut (pic 12), and the final shaping was achieved after a lot of filing, giving the result shown in pic (13). Countersunk holes were drilled in each end of the trigger guard, and corresponding holes drilled and tapped in the cylinder and grip. Pic (14) shows the trigger guard screwed in place on the pistol.




The final piece of the construction work was to make the grip plates. The patent drawings shows them to be made of wood, each fixed to the grip frame by two countersunk machine screws, and having a profile that tapered from the base to the top. Two suitable sheets were cut from a large block of walnut as shown in pics (15) and (16). These were then tapered as shown in pic (17), using an end mill fitted in my lathe. It is great that a metal-turning lathe can be used for accurate wood shaping like this, and it has solved all sorts of woodworking problems for me which would otherwise have been very difficult with ordinary woodworking tools. The same versatility can’t be said for using a wood turning lathe on metal !
The walnut sheets were then cut to the shape of the grip frame and drilled with countersunk holes to take the grip screws. The patent shows the screws to bed into grommets rather than make direct contact with wood, and so I made four brass grommets (pic 18) which were a press fit in the grip plates. Pic (20) shows the grip plates screwed in place on the grip frame.



At this point the plates were flush against the edges of the frame, but in the patent they are depicted as being slightly smaller than the grip frame, so that a narrow border of the metal frame was exposed around the grips. The grips were then slightly reduced in size to create such an effect. After two coats of thinned down polyurethane varnish, with steel wool rubbing down between each coat, the result was as follows:





With all the machining work completed and everything fitting together OK, it was time to think about the cosmetic finishing touches. There was the metal finish to choose – vintage blue, modern blue, or nickel plating, but before that there was the all-important lettering to consider. I wanted to have the lettering in two locations on the gun - on the overlever there would be indicated the identity of the pistol, its patent number and the fact that it was a reproduction, and on the grip frame where it would be concealed by a grip plate there would be my personal details. The important thing was to ensure that the gun was permanently recorded to be a reproduction, so that at some future date it couldn’t be passed off as, or mistaken for, an original protoype.


The system I use for lettering I have described before and involves first producing a protective resist on the metal surface with the lettering
areas removed accurately by a photo process, and then etching the metal away in the exposed areas by electrolysis. It is a tricky process and quite time consuming. It is also the most stressful, because if you get it wrong it could disfigure your hard-won project for ever. It is well worth the effort though, as I have come across many airguns with no lettering on them and it is so frustrating knowing that their history will probably always be a mystery.
Picture (21) shows the blue photoresist coating on the grip frame with a transparent sheet printed with the lettering placed on top. After exposure to uv light and washing off with sodium carbonate solution, the resist film in the lettering areas is removed to expose bare metal. Pic (22) shows the grip frame after electroetching away the metal in the unprotected areas and then removing the rest of the blue film.
Pic (23) shows the lettering produced on the overlever.




It was decided to give the gun a deep black hot-blue finish, rather than a more muted vintage blue finish, as this was less time consuming and in any case the project was not intended to produce a simulation of a 1926-made prototype, but to be a 2018 interpretation of a 1926 design.

So how does it perform?

I decided to fit the pistol with a Webley Mark 1 pistol spring, which meant that I could directly compare the performance of my pistol with that of the all-conquering Webley pistol design of the same era. The dimensions of the two pistols are very similar, with the same cylinder diameter and near identical swept volume. The Lincoln Jeffries has a swept volume of 21.5 cc, slightly less than the Webley at 22.5 cc. I am sure this is no coincidence, and Lincoln Jeffries Jr would almost certainly have used a Webley pistol for his design calculations, knowing that the Webley was about as efficient as you could get for that size of pistol and cocking effort. He would not want to market something of inferior power.

With this spring in place and the piston lightly oiled, the gun cocked and fired perfectly. The cocking sequence is very similar to the Webley although loading the pellet and closing the breech is a little more fiddly as the tap lever has to be tightened up by about one or two turns to give a tight seal.





I was surprised that the trigger was not as fierce as expected, and it gave a relatively smooth let-off not requiring too much effort. Using Webley Grand Prix waisted pellets, average weight 7.3 grains, the pistol gave a reasonably consistent muzzle velocity averaging 350 fps over ten consecutive shots (highest 356 fps, lowest 340 fps). This equates to a muzzle energy of 2ft lbs or 2.7 joules.

A good condition straight grip Webley Mark 1 was used for comparison. To my surprise this gave an identical muzzle velocity of 350 fps with the same pellets. However, this is not exactly a fair comparison, given that the pistol was probably 85 or more years older than mine. To put things in better context, a mint boxed Tempest was examined with the same pellets, and this gave an average muzzle velocity of 360 fps. So it seems that the Lincoln Jeffries design could match the power of the Webleys without too much trouble, but how did it compare in other respects? These are my observations after putting about a hundred pellets through the gun:

1. The cocking stroke is easier to start than that of the Mark 1, and requires slightly less effort to complete the stroke. However, it is (not surprisingly) noticeably harder to cock than the Webley Senior with its longer throw.
2. Although the cocking stroke is a bit easier than the Mark 1, after taking a few shots the cocking lever feels painful on the hand due to its ridged nature. In contrast the round barrel of the Mark 1 is much more comfortable for repeated cocking and firing.
3. The barrel opening and closing sequence for the Lincoln Jeffries is not too tedious, but suffers in comparison with the Webley. After loading the pellet in the breech it is much more satisfying to be able to close the barrel with a single click rather than to have to tighten up a rotating lever.
4. The fact that the front and rear sights on the LJ pistol are fixed is a big negative, but I suppose that this would have been changed if the gun had ever gone commercial.
5. Cosmetically the overlever is also a negative, and unless it could be proved that the Webley pistols frequently suffered from bent barrels, this feature would not have done the gun’s saleability any favours.
6. The one-piece trigger is not as smooth as that of the Webleys, and requires a bit more pressure.
7. The accuracy, in my limited 12 yard tests, seemed to be much on a par with the Webley.


The likely manufacturing costs of Lincoln Jeffries Jr’s overlever pistol were not likely to be any less than those of the Webley Mark 1, and would probably have been greater because of the casting/ machining complexities of the overlever with its tap loading unit, the barrel slide, and the awkwardly shaped carcase. This, combined with the shortcomings mentioned above would help explain why Lincoln Jeffries probably never took his overlever pistol into commercial production. Or at least, if it did make into production it was an extremely short-lived venture.



An original prototype

When I started this series of posts about two months ago (http://www.airgunbbs.com/showthread....ncoln+jeffries) I was talking about Lincoln Jeffries and his pistol when I said (quote) “he never brought it into production and any workshop prototypes will be long gone.” Now often truth is stranger than fiction, and this is a good example, for a few weeks later I had to eat my words. Just as I was putting the finishing touches to my gun, an actual example turned up. This was after more than 90 years of its lying somewhere in limbo! Maybe it was just an incredible coincidence, or my resurrecting this design disturbed something in the fabric of the universe. Spooky. This smacks uncannily of the Webley Whiting story, where the original also lay hidden for almost 80 years and when it was found after a diligent search it turned out that by coincidence Mac Evans had just completed making a copy based on the original patent drawings!

Pictures of this prototype have been shown in another post on this forum (http://www.airgunbbs.com/showthread....ncoln+jeffries). It is not exactly the same as the patent pistol and it has a different grip and trigger arrangement, but the basic design principles are all there, and importantly it is marked “Lincoln Jeffries” and “Prov Pat” . You can see that it definitely is a prototype of this design from the following comparison.




Interestingly the grip and trigger is taken from the Lincoln Jeffries Scout push-barrel pistol of the time. The prototype is also marked with the number 7 which raises the question whether or not this gun is an early discarded prototype or one of a short production run of the finalised version of the pistol.
I favour the early discarded prototype theory for three reasons:

Firstly, if it was a production model why would Lincoln Jeffries Jr call it the Scout when he was already selling a push-barrel with the same name?
Secondly, the pistol is marked Prov Pat, suggesting it could have been made before the final patent design was submitted.
Thirdly, the prototype seems to be rather crudely made, with for example the breech block roughly welded in place, the tap lever only roughly shaped, and a pin used for the cocking lever pivot rather than a machine screw.


It seems more likely to me that this was a very early experimental stage of Lincoln Jeffries project, and he used the available Scout grip and trigger unit for convenience while he tested out the overlever system. Once he realised the low power level that this imposed on the pistol, he would have refined the grip and trigger arrangement to give the one shown in the patent.

I suspect that there may yet be found a prototype identical to the patent design, but as it could take another 90 years to surface I am not holding my breath!

[45flint]

Simply amazing, thanks for sharing all that you did here.

[greenwayjames]

Really nice and incredible workmanship. Thanks for the progress reports, how it was made and photos. If that model was in production at the same time as the Wobley and I was in the market for a nice air pistol then my choice would have been the LJ.

[Benelli B76]

Lovely job, I call these type of personal creations works of art. That's why I also love custom knives. Its good to see guys in the UK carrying on skills that were prevalent here for hundreds of years.

Baz

[Troubledshooter]

Superb job, John.
Thanks for sharing the photographs and construction details.

[Binners]

Just Awesome!!!

[greasemonkey]

thats a truly awesome feat of engineering, i take my hat off to you Sir..

[Garvin]

It looks just beautiful. What a shame it didn't go into production, although as you say, it had serious shortcomings.

Fantastic work! Like the others, I'm awestruck. Thanks for all the updates.

[Huttles94]

Wow that looks great! Great craftsmanship! Looking forward to your next 'project' :P

[Leonardj]

Congratulations John, on completion of another superb masterpiece.
Thank you for sharing the progression of the project with your many photos and descriptions.
Truly inspirational.

[Airsporterman]

You are a talented, skilled and clever man!

Very well done!

ASM

[micky2]

Many thanks for the update and photos of a superb job of engineering. and good on you for engraving by who and when it was made.

[Shed tuner]

brilliant work, I love it.

I also quite like the looks of the thing, but you can see how anyone would figure "why not just use the barrel for cocking" the moment you look at it...

[kamyonsofor]

Well done sir exceptional work,don't 'spose you could do me a Bugatti Veyron.

[RichardH]

Brilliant as ever.

Really needs a book with all the builds in detail, I'd buy one