Cas City Forum Hall & CAS-L
CAS TOPICS => The Darksider's Den => Topic started by: Sandlapper on November 25, 2023, 03:29:45 PM
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I've been reading about the short arbor problem in past production models of Uberti percussion revolvers and the various fixes for it, and I thought I would add a data point to the argument. I just purchased a Cimarron (Uberti) M1861 London Navy with a 2022 date stamp and it is surprisingly well put together. The cylinder lockup is tight as a drum on all six positions, the arbor length looks to be right, mainspring strength not overly heavy, and trigger pull is 3.5 lbs. and clean before any tuning. Upon disassembly, I didn't notice any burrs or filings that needed cleaning up. I've got an M1860 Army w/ fluted cylinder and a 3rd Model Dragoon coming, both Uberti, so I'll see how they stack up against this one, but overall, I either got really lucky, or Beretta's QC must be getting better. Sandlapper
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My '61 Navy Uberti I bought back in about 1968 is as tight as it was on day one even after several thousand rounds through it. I am sure the arbor is short but I just tap the wedge in til it grabs a piece of folded copy paper placed between the cylinder and barrel. The paper "feeler guage" gives me a consistant gap of .007"
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That's good to know. I'm looking to get a '61 before too long.
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:) Everybody ;)
Before we get real excited. The "test" for Barrel to Arbor fit is to turn the barrel off to the side of the frame and "tap" it to the "rear." If it then overlaps the frame, the Barrel to Arbor fit is incorrect. You should also be able to turn the Barrel, on the Arbor a full 90 to 120 degrees from the frame pins. If you can't, the Bore in the Barrel Lug is Wonky and or the Arbor has imperfections.
The guns can, and will, function with these conditions present but the conditions are not optimal. Every time the gun is taken down for cleaning, it goes back together just a little different from before. Oft, a LOT different.
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That's how I fit mine. (Learned it on here, I might add.) I've seen a couple places mention Uberti is getting better at that adjustment. All of my older ones have needed significant adjustments.
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Just out of curiosity, did most of the original Colts have tight fitting arbors?
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Yes, the originals arbor fully fit the arbor hole. That is what designates the amount of endshake.
The "90° test" ( barrel at 90° and swing it down . . . ) is hogwash. The arbor has to be "dressed" to even allow that test to be done. So, you're gonna remove material from an arbor that WILL install when correctly oriented so you can prove that the arbor is short? Makes absolutely no sense. All one has to do is look for a shiny, round witness mark in the bottom of the hole. If there isn't one, it's short. You don't have to add to the problem by dressing the arbor to do an unnecessary test. Put mildly, if it's not a recent made Pietta, it has a short arbor. Haven't found one yet that was correct.
A single solid spacer is the best correction . . . avoid " shim stacks" as well as a "set screw" for the fix, they won't be permanent. If you're going to shoot smokeless with a conversion cyl, I would recommend pulling the arbor and retorquing it. This will make sure the arbor isn't "almost" loose . . . many new revolvers show up with loose arbors new in the box.
If all you shoot is mouse fart loads, you probably will be fine with it as is but I haven't and would never send one back to a customer without the correction.
Mike
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Mike, Thanks for the information. Sandlapper
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:) Well Hey there Dragoon ;)
Obviously we have a vastly different in opinion. The bore in the Uberti barrel lug and or the Arbor need dressed just to be able to put the gun together and take it down without a hammer and a disassembly tool. Needing that is ridiculous. Without dressing the Arbor Fitment, it is almost impossible to determine how much correction is required. If the Arbor won't bottom freely in the bore, it's quite WRONG.
The Other Mike
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Yessir, we disagree somewhat.
The broaching process of the wedge slot in the barrel and arbor distort the material in the same manner which is why they will allow assembly when correctly oriented. It may be somewhat difficult in some cases so reliving the edges of the slot in the arbor will allow easy assembly but it still won't allow 90° rotation (which is not needed for function). Making the diameter of the arbor smaller just for a test (to prove you're right ?!) still makes no sense. We're trying to "tighten" tolerances not add more clearancing!!
As far as the spacer size is concerned, it's not a "one size fits all" item. I've never "measured" to find the size for a spacer, it's a custom fit for each revolver. It's a five minute process to grind an appropriate spacer ( just part of the process). Once fitted and installed, it's done . . . and there'll be a circular witness mark on the spacer where the arbor contact is made.
If you really want to get into the weeds, all cartridge conversion revolvers I do have the arbor removed, the hand relief cut square (instead of the "notion" from the factory), shaft material upset and the arbor reinstalled ( heavily torqued). The barrel assembly installed with wedge in tight before the staking pin is driven in. Once the pin is in, the barrel assy will all but fall off when the wedge is pulled (still can't swing it 90°, don't need to).
That setup will allow a most excellent platform for a Kirst cylinder conversion as well as a "convertible" ( cap gun /cart.).
No disrespect, just different strokes . . . some folks shoot light, some shoot HEAVY ( build accordingly).
Mike
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I was recollecting an old steel frame Uberti '51 Navy I had back in the early 1980's that I shot so much with max loads( filled cylinder to the top with powder before seating round ball, that the cylinder wedge actually was peened by the recoil and had to be replaced. I assume that situation was the result of a short arbor, possibly an extreme example. I didn't have much gunsmithing ability then( or now), but wondered why that happened. Sandlapper
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Yes, that is what happens when the wedge is the "referee" between two assemblies fighting each other!! When the barrel assy is held "with great tension" against the end of the arbor, it's a mechanical connection that allows the assemblies to react together as a single unit.
In about 1977 I found percussion revolvers ( already was into rifles) and bought a brass Remington. Wasn't till early '80's I saw an open-top revolver and have been "smitten" ever since!! Just like you, I loaded full loads and crammed a ball or conical in and commenced to maiming wedges on a regular basis!!! Especially with Walkers / Dragoons . . . You'll also see material upset at the rear of the wedge slot in the barrel assy.
Correcting the arbor length and setting close tolerances makes for an amazing platform capable of rather surprising ability!!
Thanks to Larson Pettifogger's articles a lot of folks understand the problem and the fix!! I just wish the 90° test thing had never been mentioned. It's lead to so many folks thinking their's is right when it's not . . . the removal of material just to perform a test that is pretty predictable . . . (a thin little washer dropped in the arbor hole will tell you if it's short or not with no need to twist . . .). A "witness mark" will tell the same.
Mike
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:) Oh Bother ;)
How did Pietta sneak into this conversation?? We were discussing Uberti wern't we?? Just as a point, over the last 15 or so years, I haven't found enough error in the Barrel to Arbor fit in Pietta to be concerned about.
Regarding the 90 degree barrel twist, only enough offset is required to gauge the amount of overlap (should be zero). The problem lies with the poor matchup between the bore in the Barrel Lug and the Arbor. Mostly, out of the box, the barrel has had to be "driven" onto the arbor and the "driven" off to disassemble. Just looking for a "witness mark" in the bottom of the hole will only confirm the whole assembly doesn't fit properly.
Now, to be honest. I can't speak for Uberti guns made over the last 4 or so years as I have taken down my shingle. However, if Uberti couldn't be bothered to fix the problem over the last two or three DECADES I would not expect it to be corrected now.
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To be honest, I'd never heard of the ninety degree thing. I just rotate it enough for the barrel to be next to the frame so I can tell how much to add to the arbor.
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:) Oh Bother ;)
How did Pietta sneak into this conversation?? We were discussing Uberti wern't we?? Just as a point, over the last 15 or so years, I haven't found enough error in the Barrel to Arbor fit in Pietta to be concerned about.
Regarding the 90 degree barrel twist, only enough offset is required to gauge the amount of overlap (should be zero). The problem lies with the poor matchup between the bore in the Barrel Lug and the Arbor. Mostly, out of the box, the barrel has had to be "driven" onto the arbor and the "driven" off to disassemble. Just looking for a "witness mark" in the bottom of the hole will only confirm the whole assembly doesn't fit properly.
Now, to be honest. I can't speak for Uberti guns made over the last 4 or so years as I have taken down my shingle. However, if Uberti couldn't be bothered to fix the problem over the last two or three DECADES I would not expect it to be corrected now.
I guess I did by mentioning that they HAD corrected the problem.
Uberti's are still short ( that includes all the "factory Conversions").
You're exactly right about the witness mark . . . if it ain't there, it don't fit right. Dressing down a spacer "to fit" is quick an easy. As I said, you can dress the wedge slot corners in the arbor for easier install / removal, being able to turn the barrel 90° or any degrees makes no sense and isn't necessary (caveat: for my correction. Maybe that'll make some folks feel better ;D). As I said before, you don't need a measurement to hand fit a spacer. Too much changes when you drive the wedge in tight after all one's measuring. Fitting by hand with wedge driven in removes all "figuring" ( hard to measure " wedge driven in"). Once barrel lug meets frame, you can continue to dress the spacer (carefully) for "endshake spec." or affix the spacer in the hole and dress the end of the arbor for your "endshake spec". Simple and easy and no unneeded removal of arbor diameter material.
Mike
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Well, I've been out of town, got home and went to the PO and picked up the Uberti M60 Army(2023), another M61 London Navy (2023), and lastly a 3rd model Dragoon. Next day, I tore them down to change out the bolt springs and replace the nipples w/ Slixshots. I checked all of them with the 90 degree arbor test, and believe it or not, they were dead on. The timing was good on all, and the trigger pulls with my gauge were 2.5-3.5 lbs. and clean breaking. They were cleanly machines and polished inside and out, with no filings or roughness, so it appears Uberti may have gotten their act together as of late. Sandlapper
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Forgot to state that the 3rd model Dragoon was mfg. in 2022. Sandlapper
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That is too funny!!
Apparently you can't read !!
Enjoy the first ever Uberti's with correct arbors!!
Oddly enough, I've got four '22's in the shop that have short arbors ( of course they do!!) and (!!!) I've got a 1960 production Navy (GU) with engraving that is in "unfired" condition ( local customer) and even THAT one won't allow the 90° test to be done on it . . . and I WON'T remove any material from the arbor just to perform a stupid test!!! In fact, there's an assy number stamped on the very end of the arbor!! It's perfect so it's obviously short !!! ( THANKS PETTIFOGGER!!!!LOL)
I'd really like someone to explain HOW they got the barrel assembly to go completely on the arbor at 90° and swing it down to meet the frame !!! I've got examples from 1960 through 2023 that will not allow that to be done without removal of material from the arbor. ( they are ALL short by the way)
So, I'm calling BS on the test and the NEED ( WHY?) for it!!
Mike
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Mike, I actually said mistakenly that I did a 90 degree test, but I in actuality put barrel assembly back on the frame w/o the cylinder, and twisted just enough to the side of twin frame pins to clear them and barrel assembly would not go on arbor past frame end. Perhaps I could drive it on past frame by really hammering, but refrained from that as it seemed to fit awfully tight to me. I understand the change in cylinder/ barrel gap with a loose arbor/ frame fit that relies on the wedge taking the pounding, but these seem pretty tight. Maybe they will loosen up with shooting, bit they sure seem to be a tight fit now. You have mentioned a witness mark in the barrel assembly which I assume is a bright ring where end of arbor touches in arbor recess. Would this mark be obvious on a new revolver?
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Sandpaper, please understand that it's not you l'm calling BS on. It's the whole idea of a bbl assy "off center" test in the first place. It is in fact much easier to see a witness mark in the bottom of the arbor hole. All mine have indications of contact with the end of the arbor. That means, if there's no mark, there's no contact. Folks act like theirs is going to be the one that's "right" lol!! Most will lock up the cylinder when the wedge is driven all the way in . . . more proof of a short arbor. If your endshake measurement changes when you "drive the wedge on in, the arbor is short. If it was touching, the endshake wouldn't change and you wouldn't be able to drive the wedge in fully.
But, folks would rather depend on a very unreliable test and claim they got the 1 in a million . . . ( they didn't).
Mike
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I'm going to go back and check for witness marks on all of these revolvers. On the four 2022 Ubertis you currently have, roughly how much distance will you have to shim to get them right? Sandlapper
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I'm going to go back and check for witness marks on all of these revolvers. On the four 2022 Ubertis you currently have, roughly how much distance will you have to shim to get them right? Sandlapper
I'll have to measure one. I fit for .0025" -.003" endshake on a cap gun so it's not a "one size fits all" spacer. I've never "measured" to get to a size because as I stated above, when you introduce the wedge under tension "clearances" get removed and all measurements go out the window.
I'll check back.
Mike
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:) Hey Coach!! Put Me In ;)
I have to agree with Dragoon (Lightning gonna strike me). Finding the ONE Uberti with correct Arbor fit is akin to finding the Holy Grail. The additional problem is an incorrect "Interference" fit of the Barrel/Arbor. The interference is the result of sloppy machine work on the Bore in the lug. Cleaning up that bore usually lets the barrel and Arbor slide together easily. If turned to one side and tapped with a mallet, the barrel WILL move to the rear. This rearward movement is also evident when the wedge is installed BEFORE the fit is corrected. As Mike said, the Barrel Breach will
back right up to the Cylinder Face, tying everything up
Actually measuring or trying to measure "now much" correction is needed is like chasing the wind. No two Uberti Open Top design guns are exactly the same. In all the guns I worked on, I never bothered to "measure" as I just fix'd the problem. There is a real quick and dirty and cheap seats way to get a real close fit. Drop a #10 split washer (I prefer Stainless) down the bore. It will seat in the drill depression at the bottom, then put the gun together and fit the wedge. Just don't forget the little washer when you clean the gun. This will work 95% of the time. I also like to clean up the bottom of the bore so it is a slip fit with the Arbor.
There are some aspects to setting up these guns that The Dragoon and I disagree on. It doesn't mean either of us are "wrong." We just get to the same finish line via a slightly different road.
Another Mike
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I'm going to go back and check for witness marks on all of these revolvers. On the four 2022 Ubertis you currently have, roughly how much distance will you have to shim to get them right? Sandlapper
Just for giggles I measured one for a Walker ( 2022) I was working on and it's roughly .122" . Mine are "rounded" on the back side so they "self locate" in the drilled end of the arbor hole.
I've had a couple of newer ones that would have been rather thin ( arbor longer than normal. Uberti may be sneakin up on "correctness !!). Don't like the idea of a "flimsy" spacer so in that case you shorten the arbor some ( a short arbor is short no matter by how much) so a decent spacer can be made.
Mike