Shimming arbor and?


October 14, 2012, 04:54 PM
This is a Pietta 1851? If I remove the cylinder and then put the barrel on at 90 degrees, then rotate the cylinder until it comes into contact with the frame a perfect fit would mean the barrel contacts the frame where the pins are with no gap or hitting the frame behind the pins. My problem my hits behind the frame pins. Now I can put shims inside the barrel until the barrel is even with the frame at the pin area.

I'm struggling in my mind what I've done by doing that? If the barrel seats on the pins what difference did I make by shimming?

Tom who is baffled.

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October 14, 2012, 05:50 PM
If the above is confusing, and you've seen the Pettifogger pictures on checking arbor length, that's what my question is about.
Arbor is to short?

Photo 43 in the link

October 14, 2012, 09:12 PM
The barrel is by Colts design supposed to contact the lower frame where the pins are and at the same time the arbor is supposed to bottom out in the barrel arbor hole making it solid or ridged and also set the barrel/cylinder gap. If the arbor is too short and does not make contact with the arbor hole in the barrel when the barrel wedge is pushed into the arbor slot thru the barrel slot it will move the barrel upwards until the barrel finally will make contact with the cylinder. You can see this happening by holding the revolver up to a strong light and looking at the barrel gap change the further you insert the wedge, it will be pie shaped or closer to the cylinder at the top of the forceing cone than the bottom. If the revolver is manufactured correctly true to Colt design the arbor wil contact the botton of the arbor hole and prevent this from happening and the barrel/cylinder gap will remain the same reguardless of how hard the wedge is pressed in. However with the short arbor problem, the further you tap the wedge in, the tighter the barrel/cylinder gap will be and the barrel will be forced upward and out of alignment with the frame and the b/c gap will be inconsistant.

October 14, 2012, 09:24 PM
I'm going to try one of the mod's Pettyfogger does either the Dillon button or the set screw & go from there.
Thanks that makes sense.

October 15, 2012, 04:06 PM
Is this an older Pietta? I haven't heard of any of the newer ones having short arbors. Now Uberti, that's a different story.

October 15, 2012, 05:28 PM
We think its an older one, no marking and was bought missing a couple of parts.
Did have a Pietta barrel and has Pietta 1851 trigger guard and backstrap.

October 15, 2012, 07:36 PM
It's not that hard to silver solder a shim onto the arbor, then file to fit.

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