Short arbor?

[brewer12345]

I see discussion of issues with a short arbor in a colt pistol and it being problematic. I don't own a colt but am toying with the idea of an 1860. What exactly is the nature of the problem? Anyone have a picture that shows what the arbor even is?

 

[arcticap]

I found these attachments in the BP Essentials at the top of the BP forum page.
The arbor is not identified but it's the equivalent of the cylinder pin on the Remington 1858.
The cylinder slides onto it, the arbor is inserted into the hole in the barrel lug located under the bore, then the wedge is inserted through the arbor slot to secure the barrel to the frame.

 

[noelf2]

There is a lot of info in this forum by doing a search. You can also google: Uberti short arbor

Read and look at the images. It's easy to remedy, and usually isn't a problem anyway.

 

[arcticap]

The short arbor is basically only an issue with all Uberti and older Pietta Colts, and hardly ever with the newer Pietta Colts.
The other makers such as ASM and Euroarms may also have short arbors, but I don't know if they all are.

The short arbor means that the arbor doesn't bottom out in its hole when assembled, which can cause an inconsistent barrel /cylinder gap each time that the gun is taken apart and the barrel is reinstalled.
The inconsistent wedge depth can change the amount of upward pressure on the barrel and arbor assembly, which can cause the barrel to flex upward and shoot higher than normal.
It can also place additional pressure on the wedge if it's not corrected, depending on how much powder is loaded and the model, such as the Walker.
Then the wedge can get battered or the wedge slots stressed.
Some folks never fix their arbor and may not ever notice any serious problem, others will notice problems especially with the barrel cylinder gap either being too large or small.
If the wedge is inserted too far in, the B/C gap will be smaller which can bind up the cylinder.
That's one sign of a short arbor.

 

[brewer12345]

Very helpful. So a new Pietta of recent production likely avoids the problem?

 

[arcticap]

Yes, the newer Piettas don't seem to hardly ever have the problem, virtually none.
Much less than 1% or 0.5% or even less.
I can't remember the last complaint about a Pietta arbor being short, maybe 1 or 2 over years.

 

[arcticap]

There have always been complaints about Uberti short arbors because they refuse to fix the production error.
They cover up the error by slightly increasing the diameter on the end of their arbor that quickly wears in, leaving the arbor noticeably short.
They make a friction fit that isn't bottomed out.
It's not that big of a deal unless a person wants a consistent barrel /cylinder gap.

 

[brewer12345]

Great. In my 1858s the Piettas appear to be of equal quality to the Ubertis, so if I decide to pick up an 1860 I will watch for a new Pietta.

 

[arcticap]

The fix can be very easy or as complex as someone wants to make it.
Just dropping some washers /shims made from an aluminum soda can into the arbor hole can fill in the space caused by the short arbor.
Or very thin brass or steel washers to act as a shim.
Some folks drill & tap a hole in the end of the arbor and insert a screw to make an adjustable "shim" which is more complicated.
Others use epoxy either in the hole or on the arbor, with or without shims, depending on how short the arbor is.
That can maybe also throw off the factory wedge position, how it lines up in the arbor slot.
Pietta basically makes a great 1860 for anyone that wants to avoid the issue.

 

[Captain*kirk]

Do a search on the forum here for "45 Dragoon short arbor" and you'll likely come up with pages and pages of great advice from Mike (45 Dragoon) who probably knows as much as anyone on this issue and is not afraid to share what he knows.
Also, the Open Range series "Tuning The Open Top Colts" article addresses this item in detail, along with his solution (Larsen E. Pettifogger)

https://theopenrange.net/tuning-the-uberti-open-top-revolvers/

 

[.38 Special]

Historically, Piettas have not been perfect either, often coming with poorly fitted bolts, timing issues, and/or roughly finished internal parts, so "pick your poison". I have heard that Pietta quality has been steadily improving, but have no recent experience with any. Until I am shown different, I will continue to assume that any stock percussion revolver is a "pre-assembled kit" which will most likely need a bit of attention before it is as good as it should be. Considering the low prices of these guns, compared with the typical centerfire revolver, that seems fair enough.

 

[Captain*kirk]

Historically, Piettas have not been perfect either, often coming with poorly fitted bolts, timing issues, and/or roughly finished internal parts, so "pick your poison". I have heard that Pietta quality has been steadily improving, but have no recent experience with any. Until I am shown different, I will continue to assume that any stock percussion revolver is a "pre-assembled kit" which will most likely need a bit of attention before it is as good as it should be. Considering the low prices of these guns, compared with the typical centerfire revolver, that seems fair enough.

That pretty much sums it up. The new Piettas are CAM/CAD and almost every part is a drop in replacement.

 

[Jackrabbit1957]

Doing the arbor fix is an essential one, especially on the big horse pistols. These tend to wreck themselves as time goes by, frame stretches, barrel to cylinder gaps opening up. 45dragoon says the short arbor creates a harmonic vibration that causes the damage. Mike is the go to guy on this subject. Fixing the arbor length on any of the Colts gives you the same pistol each time you assemble it. Doing a good precision tune also really helps these pistols, especially with installing a bolt guide and getting the timing right. These fixes and the tuning will make a revolver that shoots more consistently and accurately. 45 dragoon, Outlawkid, and myself offer these services.

 

[Cowhide Cliff]

You can almost guarantee a Pietta won't have the issue and at the same time guarantee a Uberti will.

It literally blows my mind that with this being an issue for decades on Uberti cap guns and now with the world wide web of info it has bound to come to their attention that they can't address such a simple but serious problem and fix it.

 

[Blackpowderwarrior]

My 2 Pietta 1860's were shooters straight out of the box!! Now I still did my tune ups on em but had I not done it they'd still be been fine shooters

 

[Captain*kirk]

You can almost guarantee a Pietta won't have the issue and at the same time guarantee a Uberti will.

It literally blows my mind that with this being an issue for decades on Uberti cap guns and now with the world wide web of info it has bound to come to their attention that they can't address such a simple but serious problem and fix it.

It has indeed been brought to their attention. They refuse to acknowledge there is an issue.

 

[Tommygunn]

It has indeed been brought to their attention. They refuse to acknowledge there is an issue.

I "think" they acknowledge it; a couple years ago I bought a repro of one of their Colt .31 1849 style pocket pistols that came as a cartridge conversion in .32acp. Disassembling it to clean, the arbor had a rebate at the end with a coil spring. So atleast they absolutly know their Colt Opentop cap & ball guns have a short arbor. They simply refuse to FIX IT!!!!!!

That they go to the effort to put that stupid spring there along with that rebate which means extra machining and providing the spring, rather than simply correcting the problem the right way, says something about Uberti. I dunno what .... just something ....

 

[Captain*kirk]

@Tommygunn, I think they "know about it", but by refusing to acknowledge it they are limiting their responsibility (read; "warranty") for the tens of thousands of short arbor guns out there in play. Most likely terms dictated by their legal team. Think about it; if they fix one "shorty" for somebody, they are then on the hook for every single one they have made.

 

[brewer12345]

Same deal with Benelli. Their high end fancy shotguns with the recoil reducing stuff in the stock shoot way high. It has been widely commented on and pointed out to them, but they keep cranking them out the same way.

 

[Jackrabbit1957]

Wow, first time I heard of using a spring to fix the arbor...kinky.

 

[Tommygunn]

Wow, first time I heard of using a spring to fix the arbor...kinky.

I don't think they really fixed it ....... .......

 

[45 Dragoon]

Wow, first time I heard of using a spring to fix the arbor...kinky.

Yes, kinky!!! LOL I thought about that once (before i started doing this ). I figured the spring would be the connection ( sort of the "bones" / structure if you will) and surround it with JB weld would be easy !! Big ol NOPE!!! It wont and DON'T work!!

Mike