Question about shortening arbor on Colt clone

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Tomahawk674

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I've read a lot of posts about fixing loose arbors; drilling out the securing pin and re-securing the arbor. I read that the arbor has a shoulder that prevents the arbor from being screwed in too far.

My question is, do you guys know if there is room for at least half a turn to drive in the arbor? My arbor has stretched by several thousands, no wedge fits tight and the barrel gap is massive. This is on a steel frame.

I had JB welded a shim in the front of the arbor slot that fixed the issue but it just fell out after a couple of years of use. Looking at an alternate fix.
 
Arbor is secured with a steel roll pin. If you need to shorten the arbor, trim the barrel end of it. If it was bad enough you might get a whole turn but don't bet on it.
 
Is the arbor loose? If not the wedge can be welded and built back up to fit, also a more permanent fix is to drill and tap the end of the arbor for a button head screw that is then dressed down to correct the arbor and Barrel to cylinder gap. PM me if you want more details.
 
Let me clarify that I need to shorten the arbor because the slot has moved forward in reference to the frame over years of firing. The end of the arbor is not making contact with the barrel hole, so I will use a shim to correct that problem later.

The arbor does have some play. My plan was to remove the locking pin, turn it half a turn, which would bring the slot rearward by a bit. I saw someone on youtube just beat on the wedge with a hammer to widen it. I guess that could work too.
 
If the arbor has "some play" you already have an issue. Is your gun a steel frame (I hope)? Also, what make and model? VTI and Numrich carry parts for most Piettas and Ubertis and Dixie also has some. Replacing the arbor with new is your best bet, but the slot could be weld repaired. I'm concerned about wear on the threads.
 
It is a steel frame Uberit Navy. The play in the arbor isn't too sloppy. I had resigned myself to getting a new frame years ago but no supplier carried them and eventually I was told Uberti didn't want to sell frames anymore. I guess I never thought of the arbor alone. I will check.
 
For fixing a loose arbor on my 1851 it was necessary to drill out the rear pin, unscrew the arbor, and reinstall it with epoxy in the threads. The weld has held solid over 8 months of high volume shooting. What I believe loosened the arbor was excessive loading force. I would regularly compress powder under ball with the lever with enough force to bend the lever. Since using a loading press, I’ve been able to compress full chambers without straining any parts of the gun. I load full chambers of BP for carry and 3/4 chambers of 777 in paper cartridges for target work. To load the empty chamber at the range, I’ll use the lever, but only when it’s slightly loosened and only with enough force to seat the paper cartridge with minimal compression.
 
Nope, the absolute fix for a loose arbor is to remove it, upset the material at the shoulder (doesn't take much!), and TORQUE it back in place. An oversized staking pin driven in AFTER the barrel assy is reinstalled. Nothing else is needed. This will allow full 60 gr. charges in Walkers from now on!! You'll shear a lever screw before ever pulling an arbor on an open top.
What loosened the arbor to begin with was the fact that is doesn't bottom out in the arbor hole in the barrel. Wedges work loose and beat against the contact point on the arbor and the points on the barrel. There's a good chance it was loose from the factory (have to check it in a vice) and another possibility is the rear of the arbor slot may be in line with the rear of the barrel slot. If that is the case, you'll have to cut the arbor slot a little deeper.
I don't add material to the arbor, I add a spacer to the arbor hole to shorten the hole depth. That frees up the end of the arbor to be drilled and tapped for a set screw (cutting end ground smooth and polished) for the wedge to bear against (adjustable wedge bearing). That will allow you to keep the wedge you have from now on.

Mike
 
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Hey guys, I'm working on drilling out the locking pin on the arbor. I had to stop due to time. Does someone know the length of the pin in Ubertis?
 
Thanks. Arbor is off. If I screw it taught I feel no play in any direction. With the arbor screwed taught I have a barrel gap of .013 no matter what wedge I use or how deep it goes. Get new arbor on Saturday, hoping maybe it closes that gap. If not, I'm willing to try the screw throguh arbor end method to have an adjustable fix.
 
Just tightening the arbor does nothing to solve the length problem. Either adding material to the end of the arbor or in the arbor hole (my preference) is the only way to establish a barrel/cyl clearance. A set screw in the end of the arbor is not a good method for correcting length. Either the Pettifogger "button" method (which removes the ability for an "ADJUSTABLE WEDGE BEARING") or shortening the hole by adding a spacer (which allows for the ability to install an " ADJUSTABLE WEDG . . . " LOL!).

Mike

Also, check the "looseness" of the arbor with it mounted in a vice. You can't tell just by hand. Most of the folks never know their arbor is loose unless it is REALLY loose (detected by hand!!).
 
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Got the new arbor, but I have to take it to a machinist; the shoulder needs to be milled down as the arborstops screwing in early by about a third of a turn.
 
You're supposed to torque it in place. I usually have about a 90° (1/4 turn) crush fit after I upset the shoulder. It's still going to be short so you may want to save the new one and learn with the one you have. While you have the arbor out, you may want to cut a full hand clearance notch where the "abbreviated" factory one is. I'll post a picture.
20211031_225601.jpg
Mike
 
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That means to displace a small amount of metal by carefully peening the shoulder, this is effectively stretching the arbor by a small amount so it can be torqued into its proper place. Hope this helps.
 
Update: got the new arbor fitted by a local gunsmith, only $20. I requested a crush fit and it appears super solid. This has completely solved my cylinder to barrel gap issue. I went from 0.013 to 0.005.

Hopefully I can shoot it this weekend.
 
You won't know the amount of endshake (barrel/cylinder clearance) until you get the length part done. How do you get .005" ? I suspect that if you drive the wedge on in, the barrel will meet the cylinder and lock it up.

Mike
 
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