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Author Topic: Uberti short arbor  (Read 2346 times)

Offline ssb73q

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Uberti short arbor
« on: June 18, 2019, 09:30:44 AM »
Hi, all recent BP revolvers made by Uberti have a short arbor. All recent Pietta BP revolvers (other than the Paterson) have a correct length arbor. One may ask why a correct length arbor is important? Take a new Uberti revolver and begin hammering in the wedge. Notice that the cylinder to barrel gap changes as the wedge is hammered in. Hammer enough and the gap disappears to where the cylinder is prevented from rotating. If one is interested in reproducible accuracy, the revolver gap must be held fixed. Remove the barrel and reinstall it and you have a new poi compared to the poi before. Also, the gap can change while shooting.

If you are serious about reproducible accuracy, the Uberti short arbor issue must be fixed. One way to do this is send your revolver to Goon's. There are a number of other paths to resolve the short arbor. Some drill a hole in the end of the arbor and insert a Dillon Precision index button. The button is then filed down to produce the desired gap. In the past I have solved this issue by JB Weld a brass button to the end of the arbor and filing down the button to produce the correct gap. A weakness to my past system is that is easy to over file the button. Then one must start over. Another issue is that if I want to increase the gap, I need to start over with a longer button. Of course there are probably another dozen methods to repair a short arbor.

I have recently taken another path. The short arbor end is drilled and tapped to insert a 10-32 set screw. The set screw is turned in to produce the desired gap. The set screw has a blob of nylon on the threads that keeps the screw locked in position. An advantage of the set screw is that the gap can be easily changed if ever desired. One gap for BP and another for smokeless with conversion cylinders. If happy with the gap set, adding a drop of loctite ensures it doesn't move with time. Over the last day I have replaced nine of my epoxy on brass buttons with set screws. I still have another seven Uberti revolvers to do. The photos below is a Uberti 1862 with arbor lengthening set screw attached.

Regards,
Richard
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Offline ShotgunDave

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Re: Uberti short arbor
« Reply #1 on: June 18, 2019, 10:32:28 AM »
I do something similar to the brass button method. I use a slice of a steel rod, and solder it to the end of the arbor. Then dress it down with a file for perfect fit.



I know Mike (45 Dragoon) does it the opposite. He puts the button down in the barrel recess and JB Welds it in place.

I like your method, but I can't get past that there is reduced surface area on the mating surfaces, because the set screw is smaller in diameter. I also don't like that the threads of the set screw are eventually going to take a beating, making it hard to get the screw out and possibly damaging the arbor threads. That would make it hard to repair the threads for a new set screw.

I'm positive I'm overthinking it, but it's just easier for me to solder on the button and dress it down. If I ever need to remove it, I just warm the arbor with the torch and it falls off.
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Offline ssb73q

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Re: Uberti short arbor
« Reply #2 on: June 23, 2019, 08:12:58 AM »
Hi Dave, a lot of shooting isn't showing any problems using the 10-32 set screw arbor lengthening method. No set screw adjustments have been needed. The force on shooting is to reduce the set screw loading from the wedge being hammered in. The gas pressure on shooting is trying to pull the barrel away from the frame, reducing the loading on the set screw.

The only potential future issue using the set screw is that the area of the arbor end metal has been decreased. Will that prematurely cause the end of the arbor to fail in time? Don't know, but I am monitoring gap to see if there is any change with shooting. None noticed yet.

Fundamentally, I dislike doing any modification to original design. The correct cure for short arbor Uberti's is a correct length arbor. Pietta can get it right. Why can't Uberti?

Regards,
Richard
« Last Edit: June 23, 2019, 08:17:59 AM by ssb73q »
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Offline Rebel Dave

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Re: Uberti short arbor
« Reply #3 on: January 21, 2020, 01:50:27 PM »
Hi All
I do the same as Shot Gun Dave . I silver solder a pad on the end of the arbor. It work good for me, and as SGD says it can be reversed.

Dave
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Offline ShotgunDave

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Re: Uberti short arbor
« Reply #4 on: January 21, 2020, 02:33:35 PM »
Hi All
I do the same as Shot Gun Dave . I silver solder a pad on the end of the arbor. It work good for me, and as SGD says it can be reversed.

Dave

It's a great way to do it Dave.

Richard's way works well too. There are several ways to do it, it's just all in what you're comfortable doing. I will say this, any way you do it is better than leaving the arbor short. The gun will beat itself up in short order if you don't fix it.
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Offline Dellbert

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Re: Uberti short arbor
« Reply #5 on: May 06, 2020, 07:34:44 PM »
I'm looking for the kind of button I need to use to make the arbor on my Uberti Colts longer I've never done one for my self. I would like to Silver solder one on and hope it will work.

Offline 45 Dragoon

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Re: Uberti short arbor
« Reply #6 on: May 06, 2020, 08:21:31 PM »
Wow! Don't know how I missed this !!  Thanks for the mention Richard!!

Well, I can say y'all are definitely on the right track!!! Lol!

You can use the head of a  s.s. #14  pan head screw (Walkers/Dragoons) or a #12 pan head screw (Armys/Navys) as a source for a spacer. Just cut the threaded shaft off. The rounded part of the head sits nicely in the tapered end of the drilled arbor hole. The (now) flat surface gives a nice full size contact area for the arbor end to meet. Reduce the thickness of the spacer until you get to within a few thousandths. Then the spacer can be "installed" in the arbor hole and the arbor can be reduced to "fine tune " the barrel/cylinder clearance.  There ya go!!

 Since some of you are into drilling the end of the arbor, you can drill on into the wedge slot, thread it (I use  1/4" x 28 set screw, cutting surface ground flat and polished),  and use the screw as an adjustable bearing surface for the wedge.

Mike
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« Last Edit: May 06, 2020, 08:24:28 PM by 45 Dragoon »

Offline Dellbert

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Re: Uberti short arbor
« Reply #7 on: May 07, 2020, 09:44:19 PM »
Thanks Mike. I'll have to give it a try. :)

Offline Navy Six

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Re: Uberti short arbor
« Reply #8 on: May 09, 2020, 10:49:12 AM »
Mike, thanks for the tip about the pan head screws. So far I've used SS washers to "fill the hole" in the barrel lug. It has worked effectively and been reversible if necessary, but the idea of completely filling the cavity is appealing. I like the idea of no permanent modification to this area. Your  willingness to share your experience is greatly appreciated. 
« Last Edit: May 09, 2020, 10:55:06 AM by Navy Six »
Only Blackpowder is interesting.
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Offline Hawg

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Re: Uberti short arbor
« Reply #9 on: May 09, 2020, 12:07:01 PM »
You can use the head of a  s.s. #14  pan head screw

Why use a Harley screw when there are cheaper options? (7+"................................................................Sorry I couldn't help myself. :P
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Offline 45 Dragoon

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Re: Uberti short arbor
« Reply #10 on: May 09, 2020, 06:31:32 PM »
Ha!!! I understand Hawg !!! ( ya knuckle head!!! )  *6'


Thanks Navy Six !  Glad to help! I get that some want it to be "reversible" but I can't understand why someone would want to take it back to a "broken" state ?  (*3


Mike
« Last Edit: May 09, 2020, 06:40:20 PM by 45 Dragoon »

Offline Hawg

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Re: Uberti short arbor
« Reply #11 on: May 09, 2020, 08:08:53 PM »
Ha!!! I understand Hawg !!! ( ya knuckle head!!! )  *6'


Thanks Navy Six !  Glad to help! I get that some want it to be "reversible" but I can't understand why someone would want to take it back to a "broken" state ?  (*3


Mike

I had a dragoon I used washers on but I took them out when I sold it.
Do not meddle in the affairs of dragons, for thou art crunchy and tasteth good with ketchup.

Offline 45 Dragoon

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Re: Uberti short arbor
« Reply #12 on: May 09, 2020, 09:42:03 PM »


I had a dragoon I used washers on but I took them out when I sold it.
[/quote]


What!!! Sold the man a broken gun?!!! Lol!
  Well, I guess you told him how to fix it  .  .  . 

Mike

Offline Hawg

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Re: Uberti short arbor
« Reply #13 on: May 09, 2020, 10:53:29 PM »
He said he was gonna send it to you to have all sorts of disgusting things done to it lol :P :P :P
Do not meddle in the affairs of dragons, for thou art crunchy and tasteth good with ketchup.

Offline 45 Dragoon

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Re: Uberti short arbor
« Reply #14 on: May 10, 2020, 06:53:08 AM »
He said he was gonna send it to you to have all sorts of disgusting things done to it lol :P :P :P


  Haaaaaaa!!! Now I see your angle on all this kinda thing!!!  (Good man Hawger!! Thanks!!)

Mike
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