open top base pin wiggles

[delmar]

I was given an 1851 brass frame Uberti that is in need of repair. The wedge  is too narrow , the wedge
screw is missing, and one of the little barrel pins is missing. Those parts add up to $20 at VTI. My main
concern whoever, is that the base pin (that the cylinder slides onto) has a little wiggle. Is there a fix for that?

[Coffinmaker]

Delmar,

Actually ..... no.  It is not uncommon for the Arbor (base pin?) to have a little wobble.  Especially in a brass frame and if the gun has a few miles on it.  Once you have a guide pin (bottom of the frame @ front) and wedge that fits, the arbor won't move much with the wedge in place.
It is highly likely the arbor doesn't seat at the bottom of the bore in the barrel.  You'll need to check that.  Often what appears to be a lose wedge is actually a too short arbor shaft.  There is a way to fix that fit, but first get your locator pins installed and the new wedge.  Then you can determine if the arbor is too short.

Coffinmaker

[delmar]

Delmar,

Actually ..... no.  It is not uncommon for the Arbor (base pin?) to have a little wobble.  Especially in a brass frame and if the gun has a few miles on it.  Once you have a guide pin (bottom of the frame @ front) and wedge that fits, the arbor won't move much with the wedge in place.
It is highly likely the arbor doesn't seat at the bottom of the bore in the barrel.  You'll need to check that.  Often what appears to be a lose wedge is actually a too short arbor shaft.  There is a way to fix that fit, but first get your locator pins installed and the new wedge.  Then you can determine if the arbor is too short.

Coffinmaker

Are you saying that the arbor was too short when it was installed, or are you saying
 it somehow becomes too short?

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[Dirty Brass]

Sometimes you can turn the arbor out if it is threaded. I did this on one of my 1860's years ago...

[delmar]

I just got off the phone with VGI gun parts. The wedge, barrel pin and wedge screw I need should be here
in 2-3 days! When I get the right wedge in I should have a much better idea where I'm at.

[Coffinmaker]

Delmar,

The arbor was too short originally.  Uberti Open Top guns, Black Powder, 1872 Open Top, Conversions, the whole gamut are famous for poor arbor fit.  The problem isn't actually the arbor,  The problem is the bore in the barrel the arbor fits into.  Its too deep and not finished with an end mill to to the correct depth.  There are a number of ways to correct the problem, starting with "cheap fix" to having and expensive relationship with your machinist.
After you have all the correct parts for your gun installed, you can determine the how bad the arbor/barrel relationship is.  Pettifogger did an excellent article series for the Cowboy Chronicle detailing a really good method for fixing the problem without breaking the bank.

Coffinmaker



 

[Dirty Brass]

I'm a little confused (nothing new there  ). Isn't the arbor set into the backframe? I don't understand how too deep of a hole would effect the arbor, as it will only go in up to the point where the frame and barrel section meet, correct? I can see where the wedge slot location could effect it, or if the arbor was too short or too long and doesn't line up with the wedge slot (s) in both pieces. Please help me understand. As usual, I appreciate the feedback and knowledge you guys have. 

[Coffinmaker]

Yes, the arbor is set into the back frame.  The basic design of the gun requires the barrel to seat against the back frame and the arbor to seat SOLIDLY into the barrel.  If the arbor doesn't seat solidly, the barrel floats on the arbor and each change of the wedge changes barrel/cylinder gap, sight alignment/point of impact and stresses the arbor up and down.  As a result of all of the foregoing, the wedge is never actually tight in the manner it was intended and the gun shoots loose.  The barrel actually tilts up as the wedge is driven home.  It's not suppose to do that.

Coffinmaker

[Dirty Brass]

Ah I see. Thanks Coffinmaker. It makes sense that the tighter the fit the better the results.

[Montana Slim]

IMO, the biggest problem with steel arbor in the brass frame is that galvanic corrosion can take place and result in a loose fit of the threads.
Removal of the arbor, coating with loctite and reassembel will help, and prevent galvanic corrosion.
If it doesn't already have a locking pin, you can add that as well.

Slim
Who's first revolver (age 14) was a brass-framed 44....it got loose many years ago, did the above & it still shoots ok.

[delmar]

Sometimes you can turn the arbor out if it is threaded. I did this on one of my 1860's years ago...

There seems to be a pin that needs to be removed before the arbor can be turned out. Anybody have any ideas how to remove the pin?

[Coffinmaker]

Delmar,

The arbor is retained from turning by that pin, which is a press fit.  The only way to get it out is to drill it out.  Then you either have to drill and tap a new hole for an allen screw or, get  and press a new pin in.

You real sure you want to remove it??

Coffinmaker 

[delmar]

Delmar,

The arbor is retained from turning by that pin, which is a press fit.  The only way to get it out is to drill it out.  Then you either have to drill and tap a new hole for an allen screw or, get  and press a new pin in.

You real sure you want to remove it??

Coffinmaker 

Well, I sort of liked Montana Slim's loctite suggestion, but it won't  be my first choice if I have to go
through all that! I'm sort of hoping the new wedge and barrel pin will take care of the problem so that I can
at least shoot straight with light loads!

[Montana Slim]

Getting the pin out can be an adventure in frustration....or it might just drop out.
Typically, the factory pins are not a drive-in tight fit. They are retained primarily by the peened edge of surrounding metal you can see.
Also, the factory pins are usually fairly soft.

You can start to drill with a bit the same size as the pin, or next one larger. If you're able to at least cleanup the peened over metal, it may just drop  out. To do that part, holt the arbor up and tap the end of the arbor lightly. The lock pin may work loose and fall out or partway so you can grab it.

I've had to replace a few lock pins on new pistols because they were working loose & backing out, just from firing. All were easy to fix, I replaced with slightly oversize steel dowel pins. Many thousands of rounds later, they are still tight.

Regards,
Slim

[delmar]

I have been doing a bit more diagnosing while I am waiting on my parts, and I think that I have determined
that the arbor hole is in fact a little to deep. I dropped a washer into the hole and put the barrel in place, and
with just a bit of pressure it seats as deep as it ever did.


Then just to make sure I dropped in a second washer. With two washers it will not seat as deep as it should.
In fact, the gap between the barrel and the frame is almost exactly the width of one washer.



I have also discovered that one of the holes that the barrel pin goes it to, is stretched just a little. It is no
surprise that the hole that is stretched is the one where the pin is not missing. It seem to me that a previous
owner of this pistol continued shooting it, for a while, after the pin was missing.


I have two possible fixes in mind. One would be to solder the pin in place on the frame side. The other idea
comes from the fact that the original pins are larger on the barrel end than they are on the frame end. If I
can find or make a pin that is the same diameter on both ends, I sound be able to drill the stretched pinhole
 and be good to go. It might be even possible to simply press the pin into the brass on the frame side.

[Dirty Brass]

Just my opinion, but these pins only function as anti twist deterants. Pressing a new one in would work just fine - I'f find some roll pins of the same diameter and use them if you can't find some hardened steel rod or drill rod. If I'm wrong, someone please jump in and educate me too..... 

[delmar]

I just got off the phone with VGI gun parts. The wedge, barrel pin and wedge screw I need should be here
in 2-3 days! When I get the right wedge in I should have a much better idea where I'm at.

I got my parts in from VGI, but I am back to square one. The wedge they sent is exactly the
same size as the one I have that doesn't fit. I was starting to wonder if the gun really isn't an Uberti, but I
checked and it defiantly has the Uberti logo. I guess I'll call VGI Monday and see if they have an idea what the problem is.

[Montana Slim]

Those small pins are "dowel" pins. A good hardware store should have what you need.
One end of a dowel pin is a tad smaller than the other. Insert this end into the frame.
Add a drop of permanent (red or similar) loctite into the hole first.

On the end of the arbor, you can drill & tap a hole, then install a screw with a head the same or smaller diameter as the arbor. Then fit and/or file the head to obtain the correct spacing. This is a period correct repair....seen it on several old Colts. One in my family collection has the screw slot there and you can turn the screw to continue adjusting, if need be.

Regards,
Slim

[delmar]

OK I shot the Colt today. Here is a video of me trying to shoot gunfighter style with the Colt and the Euroarms Remie.

http://s901.photobucket.com/albums/ac214/deardelmar/?action=view&current=shoot.flv

I was having a little trouble with the caps fitting correctly. I guess I should have worked that out before I tried shooting with both hands. Also the plastic bullets don't seat as tight in the Colt as they do in the Remies, and one of them came unseated and shut me down. I guess I'm going to need to paper patch them for the Colt.


I'm not sure if I'm ever going to get to shoot real lead balls in the Colt. The wedge I ordered for it was to small. The Gal at VTI gun parts says if that one doesn't fit the only thing I can do is buy one for a Walker and "whittle it down". In the mean time I made one out of a piece of Maple. It works fine for shooting plastic bullets, but I'm not sure it would hold up to the recoil of even a light load with real lead.

[Dirty Brass]

I would definately not recommend a maple wedge for any loads with heavy projectiles.

Is there anyone that can measure your width and make one from 4140 or better steel for you?