My arbor has a hole in it???

[Columbus]

Recently picked up a Pietta 1860. Started to disassemble - wedge was tight, had to use a drift to tap it out. When I put it back together the wedge was loose, pulled the bbl again and that's when I noticed that a hole had been drilled into the arbor. All I can surmise is that it must have something to do with a short arbor issue and something was in that hole to take up the slack. Whatever it was must have fallen out when I first pulled the bbl and I've no idea what it might have been or where it went. I've swept that kitchen floor more times this afternoon that I've done in weeks and I can't find anything. The hole is not threaded and is about 2.5mm deep. As it is now, the wedge is loose, the only thing holding it in is the hook on the spring and with that there's too much cylinder gap. Any suggestions or comments would be appreciated.

 

[ord sgt]

Look under every appliance. Look with a flashlight and use something to slide under to sweep out anything which might be hidden from view. Maybe even use a magnet.

 

[Phil Coffins]

Don’t waste your time looking for what was there. Place the barrel on the arbor at 90 degrees and measure the over lap then make or find a plug to put in the arbor hole if needed. The wedge fit is another issue to deal with and requires a wider wedge or drill that hole and tap it for a set screw to adjust the wedge fit. You may of bought someone’s problem but it can be dealt with.

 

[SDSmlf]

Couple of questions.
1. Have you checked in the bottom of the hole in the barrel?
2. If you assemble the gun and drive the wedge in pretty tight, does the cylinder start to bind?

 

[SDSmlf]

Don’t waste your time looking for what was there. Place the barrel on the arbor at 90 degrees and measure the over lap then make or find a plug to put in the arbor hole if needed. The wedge fit is another issue to deal with and requires a wider wedge or drill that hole and tap it for a set screw to adjust the wedge fit. You may of bought someone’s problem but it can be dealt with.

Below is a photo I have posted before of a Pietta (sold by Navy Arms) before the change to CNC machining. Arbor is about a .100” short. Shows what @Phil Coffins is referring to I believe.

 

[Columbus]

Couple of questions.
1. Have you checked in the bottom of the hole in the barrel?
2. If you assemble the gun and drive the wedge in pretty tight, does the cylinder start to bind?

Yes I checked the hole and there's no driving the wedge in - it's not tight anywhere - moves freely back and forth - the spring catches on the off side and keeps it from falling out.

 

[Columbus]

Below is a photo I have posted before of a Pietta (sold by Navy Arms) before the change to CNC machining. Arbor is about a .100” short. Shows what @Phil Coffins is referring to I believe.
View attachment 109838

Appears to be out of round on mine - can't push the bbl on all the way unless it's line up properly. (not out of round, forcing cone is relieved in one spot for arbor clearance, can't put it on any other way.
.

 

[Columbus]

Is it normal to have a hole drilled all the way through the bottom of the arbor hole?

 

[45D]

Yes, the 90° thing isn't a valid test. The only true test is a washer dropped in the arbor hole and reassembly. Then it's just "how many washers " . . .

Mike

 

[SDSmlf]

Appears to be out of round on mine - can't push the bbl on all the way unless it's line up properly. (not out of round, forcing cone is relieved in one spot for arbor clearance, can't put it on any other way.
.

Sounds like you have one that the arbor was ‘hand finished’ on a belt sander or similar. Have owned more than one like that, though have not seen the ‘out of round’ condition with Piettas, but I have found it to be typical on Ubertis.

If the arbor is short, you will be able to drive the wedge into the point where the cylinder starts to bind. If you have a short arbor, you can shim it to get the correct fit, although washers will give you general idea as to what you need, unless you have some very thin washers to dial it in, it is tough to get close. I like to get the gun setup within .010” to .015” max, preferably less. Tough to do with .030” or more thick washers in my opinion.

 

[44Bro]

Look around on the floor and bench for a small (~3/8" dia) piece of metal. It'll look like a small coin. A prior owner most likely already made the shim, and it took off when you removed the barrel not knowing it was there.

 

[wb78963]

exactly why I use the back of a magnetic sign on my work area. Little steel parts hit and stick.any place that makes signs will have scrap or outright buy a piece.
respectfully
Bunk

 

[Columbus]

Look around on the floor and bench for a small (~3/8" dia) piece of metal. It'll look like a small coin. A prior owner most likely already made the shim, and it took off when you removed the barrel not knowing it was there.

What I don't understand it the hole drilled in the arbor and one drilled all the way through the bottom of the arbor hole.

 

[hawkeye2]

What I don't understand it the hole drilled in the arbor and one drilled all the way through the bottom of the arbor hole.

Do you mean a hole drilled all the way through the barrel lug like they just kept on drilling the arbor hole deeper? Could they have meant to tap it and put in a long screw that would come up against the end of the arbor to set the barrel depth on the arbor (adjust the barrel/cylinder gap that way)?

 

[Crow-Feather]

View attachment 109899

 

[Crow-Feather]

It appears that the arbor is threaded - maybe for adjustment?

 

[hawkeye2]

If you mean the area just under the number 15 those are circular cuts to hold lube and hopefully prevent fouling from binding it up. Colt's idea.

 

[44Bro]

That dimple in the end of the arbor is for a center on a lathe. It's an artifact of the manufacturing process. The over drilled lug, is just Luigi getting carried away when fitting the barrel.

 

[bang]

Measure from fwd face of frame behind cylinder to frame and barrel assembly mating surface. Add depth of arbor hole.
Measure length of arbor.
Figure difference and that should get a good starting point.
Or, put feeler in cylinder gap that just allows solid contact of frame and barrel assembly mating surfaces then start with that thickness.
Shim should make solid contact of arbor just as the frame and barrel assembly mating surfaces make solid contact.
Make sure cylinder gap is square to cylinder and barrel.
As far as turning the barrel assembly to do this check, it does work to get same starting point. I've done several by doing it. Had one that would not turn. A bit of ink to find interference and a fine file took care of it easily with no ill issues at all.

 

[Capnball]

Look under every appliance. Look with a flashlight and use something to slide under to sweep out anything which might be hidden from view. Maybe even use a magnet.

Magnets have saved me from having to have irreplaceable parts remanufactured. I have a whole assortment of them. I find stuff I ain't even looking for!