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Don't forget Kirk Merrington; he's as good as there is on spray welding. He'll do the entire job or just the welding and you take it from there. Gil


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I have removed one compensation or ball screw from a Lefever 20. It measures .522" (no taper apparent) and 22 threads per inch. It is a slotted screw and came out easily...which I did not expect. I only tried that because the frame was to be annealed for engraving and didn't wish to mess with the temper of the screw.. Fortunately I had the forethought to apply witness marks so the screw will go back in to the same depth. The threads in the frame are like Miller mentioned, tapered on the inside end which I assume is from the tap?


Sam Welch
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Sam;
I pulled the ball screw out of the junker. .522" x 22tpi. The diameter of the ball itself just ahead of the threads measures about .460", so I guess the ball size was what I was remembering as "About" 7/16" (.4375").

I, of course, do not know how Lefever threaded the frame but from being a machinist the thread has the features of having been tapped with what we today call a starter or taper tap. This will make a straight thread if run far enough in but would appear Lefever stopped short of cutting the full thread. This allows the straight threaded screw to start to bind as it enters the tapered portion or "Lead" of the tapped hole.
Taps today generally come in one of three configurations, starter/taper, plug or bottom. The taper tap has the longest lead or taper with the plug tap being a more or less general purpose tap. The bottom tap is normally used only following a plug tap when necessary to have full threads to the bottom of a blind hole.

This one is from an H grade SN 46,128. The other one I have measured was from an FE SN 38,025. I am positive they measured the same.

Do realize that after annealing & I assume re-hardening the screw may, or may not, seat to the same exact depth. The length of the bar may change a few thousandths.


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Thanks for the info Miller, I will keep that in mind and hope for the best.


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I have some drawings I made of four different Lefever compensating screws. Unfortunately, these were not done at the same time, and I did not take measurements in the same places on all of them.

The compensating screw from an early D.M. Lefever crossbolt gun of unmarked grade (about 7D or 8E from engraving and features) has an O.A.L of .641" The O.D. at the front (screw slot) end is .520" and the dia. of the threads at the ball end is .515" --The root of the threads at the front is .480" and the root of the threads at the ball end is .476" - So there is a taper of about .004 to .005" over the length of the threaded portion. This threaded portion is .312" long, and there are approx. 8 threads in that distance. I apparently did not have a thread pitch gauge handy at the time. The OD of the hemispherical portion is .457"

I also have measurements of two Syracuse Lefever sideplate guns that are nearly identical. One is an H grade SN 447xx and an I grade SN 553xx. Both of these also show a measurable taper the same as the one from the crossbolt gun. My drawing indicates that I measured these with a Starrett thread pitch gauge and got 22 tpi. Both of these are also a bit longer at .646 OAL.

This very small sample indicates that Dan Lefever likely used the same size compensating screw in his sideplate and his crossbolt guns, and this part of his design made the transition to the later crossbolt guns. Apparently, the patent protection ran out, but other than the rare J.A. Prechtel guns from Cleveland, I know of no other gunmaker who used this compensating hinge system.

Another drawing I have is of a compensating screw that came from a bag of parts I bought on E-bay. I do not know what grade or serial number these parts came from. This one is .645" long, and the thread diameter at the front is .521"--- The root of the threads is .484", and I noted that this one has no taper to the threads. All of the measurements I took on this untapered one are very close to what Miller measured from his junk H grade.

I don't know how easy it would be to measure the taper of the female threads in the action knuckle. I suppose it could be done with plug gauges, however, I have never checked. But you could certainly say there was likely a taper if a compensating screw that had no taper to the threads was not able to be threaded clear through. It would have to be a tedious cut and try process to stop tapping the female threads at just the right point where the screw was snugly seated, and the breech end was correctly on the face. If you went a bit too far, backing out the screw to correct the barrel fit would leave it rather loose. I haven't removed a great many of these compensating screws, but it seemed as if a couple had some sort of black compound like pitch on the threads, and I wonder if this was some early version of thread locking compound. It sure didn't help penetrating oil get down into the threads.


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As I said I have only measured these two screws. Actually, I did not originally take either of them out, they had both been taken out by someone else before I removed them for measuring.

Actually, the true determining factor for whether a thread is straight or tapered is Pitch Diameter. On both of these two screws, I did measure the pitch diameter & they were both straight & as I recall were identical. Also, the od of them both measured straight.

I have no doubt that some of these guns were built with tapered threads, there seems to be ample evidence of this, I have no idea which type is predominant.

Either method would require precise control of the tap for proper seating when the gun came on face. The tapered method would also require precise cutting of the screw. From a machinist's viewpoint, I would have to say using the straight screw would be the easier of the two.

As Keith has said measuring the pitch diameter of an internal is pretty well universally done by plug gages. I have made no attempt to measure this, can only say that on these two guns, just going by feel the screws run with seemingly the same clearance un till the taper of the lead of the tap is encountered. Understand when using the type of tap I am referring to if it were run to where the lead exited the hole the end result would be a straight thread. The lead is to distribute the load over the first so many teeth, rather than the first tooth carrying the entire load.

A taper thread tap, on the other hand, is tapered for its full length. Pipe threads are the most commonly encountered taper threads.

Keith, I may have the name wrong but seems I recall there were some of the Crossbolt design guns sold under the name Waverly. It has always been a Wonder to me, why no one else picked up this feature after the patents expired.


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Ken Eversull confirmed he does not spray weld but he did take the job and says he has done many other LeFevers with this issue. Many thanks for the information.


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I'll throw this out there for Lefever guys. Pretty sure Bill Schwarz in Ellijay used to specialize in Lefever restoration. I believe this was before he came to his senses and moved south of the Mason-Dixon line, although I'm sure he still works on Lefevers.

I've had good luck with him tightening up two older German guns, one by welding and filing the barrel hook and the other by welding and filing the sliding underbolt. Both jobs were flawless and the guns locked up tight as new afterwards. In any case, he will never take a ball peen hammer and 'tighten' your gun (unless you are foolish enough to request it).

He also does his own rust bluing and case colors. I had him rust blue a third German gun, and the lettering on the barrels came out sharp, the barrel flats were not blued over and came out looking original.

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I had one vintage SxS tightened with welding...I knew it was at best a temporary band aid.

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Originally Posted By: steve f
I'll throw this out there for Lefever guys. Pretty sure Bill Schwarz in Ellijay used to specialize in Lefever restoration. I believe this was before he came to his senses and moved south of the Mason-Dixon line, although I'm sure he still works on Lefevers.

I've had good luck with him tightening up two older German guns, one by welding and filing the barrel hook and the other by welding and filing the sliding underbolt. Both jobs were flawless and the guns locked up tight as new afterwards. In any case, he will never take a ball peen hammer and 'tighten' your gun (unless you are foolish enough to request it).

He also does his own rust bluing and case colors. I had him rust blue a third German gun, and the lettering on the barrels came out sharp, the barrel flats were not blued over and came out looking original.


You may be mistaken and confusing him for Bill Scwartz who was the barrel man and part owner of the Lefever Arms Gunsmithing operation in Lee Center, NY. That one never left that area of NY. He passed a couple years ago.


B.Dudley
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