Trying to understand this “short arbor” on Uberti revolvers

[Lippy984]

I can definitely see an issue with people Over greasing the arbor. Someone posted they smear a little white lithium grease just inside the arbor hole on the cylinder, that way when it slides on it covers just enough of arbor to keep it lubricated, yet creates a dam or seal to keep fouling out. That worked quite well for me. I haven’t fired my gun since setting correct arbor length and cylinder gap, but prior to that I could physically see as I cocked the hammer, the crud on the cylinder face was being scraped off. Thus making it harder for the cylinder to rotate

 

[Jerry Simon]

Sorry for this stupid question. I am very new to BP. I have an Uberti 1851 Navy and I have been following this thread(and others on this subject). I have spent close, if not more, a hour trying search the web trying to under what is the arbor. If anyone can kindly let me know, pictures would help, I would definitely appreciate it.

 

[Phil Coffins]

The post that the cylinder turns on. Note the rectangular hole that the wedge fits into.
IMG_0175 by Oliver Sudden, on Flickr

 

[Sam squanch]

This can all be avoided. Just shoot a single shot pistol.....

 

[RjSixgun]

This can all be avoided. Just shoot a single shot pistol.....

or by buying a Remington!!

 

[wb78963]

Remingtons are bu** ugly and carrying six single shots is a bit of a load.
Shimming the arbor hole or end of the arbor is the only solution to have a solid frame what won't bind the cylinder.
Paraphrasing the ad "I am not arguing with you about short arbor, just trying to explain why you are wrong."
Bunk

 

[M. De Land]

Remingtons are bu** ugly and carrying six single shots is a bit of a load.
Shimming the arbor hole or end of the arbor is the only solution to have a solid frame what won't bind the cylinder.
Paraphrasing the ad "I am not arguing with you about short arbor, just trying to explain why you are wrong."
Bunk

With an open frame guns you are never going have a rigid design as you do with a solid frame gun. The arbor plug does not change the design parameters because the load pressure at firing is away from the end of the arbor and onto the wedge, slots and lower bridge. An open top revolver is designed to flex and all the parts (wedge, slots and lower bridge ) that arrest the load toward the muzzle are what matter to accuracy and reliability.
A comparison I like to use is the difference in design of a suspension bridge as opposed to a rigid bridge.

 

[Pete G]

A comparison I like to use is the difference in design of a suspension bridge as opposed to a rigid bridge.

There is no such thing as a rigid bridge, they all flex.

 

[Bad Karma]

There is no such thing as a rigid bridge, they all flex.

Probably the same is true of revolvers of most common designs.

 

[RjSixgun]

Didnt Colt do away with the open top design in in the 1873????? Guess it wasnt all that great after all
LOL

 

[Old Hawkeye]

Didnt Colt do away with the open top design in in the 1873????? Guess it wasnt all that great after all
LOL

Bill Hickok may have had a different opinion. He was carrying a pair of Navy Colts when he was shot in the back of the head in 1876! If the assassin would have been facing him, he may have found the 1851 Colt to be a very well designed. I find my Navy Colts to be more ergonomic & "pointable" than my SSA Colts & after using both, understand why "Wild Bill" preferred the Navy over the SSA. Handguns are more subject to "how they fit your hand" than other firearms, so it's a very personal & subjective thing more than it is the "design". Especially when your life is on the line!

 

[Kansas Jake]

Bill Hickok may have had a different opinion. He was carrying a pair of Navy Colts when he was shot in the back of the head in 1876! If the assassin would have been facing him, he may have found the 1851 Colt to be a very well designed. I find my Navy Colts to be more ergonomic & "pointable" than my SSA Colts & after using both, understand why "Wild Bill" preferred the Navy over the SSA. Handguns are more subject to "how they fit your hand" than other firearms, so it's a very personal & subjective thing more than it is the "design". Especially when your life is on the line!

Actually Hickok was carrying an unmentionable at the time of his death a S&W model 2 in 32 rimfire. He did carry Navy Colts most of the time when he was an active lawman.

 

[denster]

With an open frame guns you are never going have a rigid design as you do with a solid frame gun. The arbor plug does not change the design parameters because the load pressure at firing is away from the end of the arbor and onto the wedge, slots and lower bridge. An open top revolver is designed to flex and all the parts (wedge, slots and lower bridge ) that arrest the load toward the muzzle are what matter to accuracy and reliability.
A comparison I like to use is the difference in design of a suspension bridge as opposed to a rigid bridge.

A properly set up Colt open top where the arbor bottoms out in it's recess at the same time as the barrel lug meets the frame and the two are secured by the wedge pack formed by the wedge and the corresponding taper in the end of the arbor applying force rearward against the barrel slot effectively locks the two units together as a single unit. This is not a "flexible" unit but acts as a solid unit on firing.
Your comparison to a suspension bridge makes no sense whatsoever.

 

[Bad Karma]

Didnt Colt do away with the open top design in in the 1873????? Guess it wasnt all that great after all
LOL

 

[RjSixgun]

LOL
Just say, it stands to reason that even Colt realized the weakness of his design and recognized the strength of Remingtons design.

 

[M. De Land]

Of course all bridges move to a greater or lessor degree but a suspension bridge is actually designed to flex while it carrries it's intended load. If a rigid bridge were to move the same amount it would tare itself apart. The Colt revolver was designed with this in mind where as the Remington was designed to eliminate as much flex as possible..
If you ever personally test wither or not a revolver with a solid arbor fit is any more accurate then the same gun without it I think you wll have to change your opinion.

 

[rickpa]

IIRC the 1873 Colt SAA used the same grip frame as the 51 Navy. And as was pointed out, Colt went to a solid frame. Remington, Rogers & Spencer, and other solid frame designs are superior. JMHO and worth what you paid for it.

 

[Ontario47]

There are two ways to think of the wedge system in a open top revolver. One is that the wedge (when tight) completely fills the width of the windows in the left and right of the barrel, and simultaneously completely fills the slot in the arbor. This would work but is hard to machine and allows no wear of the eight surfaces involved. If you install the wedge in the barrel (or arbor), only, it goes in farther than when all three are assembled. What is happening as you assemble the gun and insert the wedge, is that the rear of the wedge is rubbing/pushing against the rear of the windows (L&R) of the barrel and only the front of the slot in the arbor, pulling the two together. The arbor bottoms out in its barrel hole and the assembly is tight. If you look the wedge is not touching the front of the barrel slots, and the wear pattern shows the rear of the wedge is not rubbing the arbor. The length of the arbor and depth of its hole in the barrel (and contact of the bottom straps) are what are controlling the cylinder gap,

 

[Bad Karma]

LOL
Just say, it stands to reason that even Colt realized the weakness of his design and recognized the strength of Remingtons design.

Of course all bridges move to a greater or lessor degree but a suspension bridge is actually designed to flex while it carrries it's intended load. If a rigid bridge were to move the same amount it would tare itself apart. The Colt revolver was designed with this in mind where as the Remington was designed to eliminate as much flex as possible..
If you ever personally test wither or not a revolver with a solid arbor fit is any more accurate then the same gun without it I think you wll have to change your opinion.

Huh! Well, this weak sister of a gun has been in service since 1965, always full power loads with ball and bullet. It’s been fired at least once a week for many years. I suppose it’s possible that it could fail at any time and it’s obviously struggling to maintain accuracy but replacing a few internal parts here and there have kept it in fine fettle... besides, nothing fits my hand like this one does. Guess I will just continue to suffer with it’s inadequacies.

Edit: forgot to add this. I have used the pistol with the factory short arbor for most of it’s life. It was short by .028”. Last year I made a steel spacer for the arbor end and I have fired over 500 rounds through it since then. The accuracy and point of impact remain constant. As with any human pursuit, some folks will try to eliminate every variable however small. Persisting on picking flyspecks out of the pepper jar until the pepper is all gone.
In pursuit of what exactly? Most of the percussion revolvers I have been familiar with (99% Uberti, Ruger, or Colt, 1st and 2nd gen) are capable of 2-1/2” 25 yard groups right out of the box assuming a good rest, good loading technique and a shooter willing to work for it. This particular gun will bench rest 6 195 grain bullets into an 1” on a good day. The bad days are all mine. The timing and lockup, condition of the forcing cone, concentricity of the chambers, bullet to bore fit, and muzzle condition (crowned or not) are much more important.
I don’t own a pistol manufactured later than 1995. I have no idea if the new cnc manufactured guns are better or worse than the older ones but I have no complaints whatsoever with the old pistols. Anyway, these are my free opinions worth at least what you paid for them. I’m old, and I ramble but I offer a lifetime money back guarantee!

 

[M. De Land]

Huh! Well, this weak sister of a gun has been in service since 1965, always full power loads with ball and bullet. It’s been fired at least once a week for many years. I suppose it’s possible that it could fail at any time and it’s obviously struggling to maintain accuracy but replacing a few internal parts here and there have kept it in fine fettle... besides, nothing fits my hand like this one does. Guess I will just continue to suffer with it’s inadequacies.

Not saying open top frames are inaccurate or unreliable just designed differently from rigid frame guns. My 60 is very accurate!