Removing Cylinder Bushing from Pietta ?

August · December 20, 2015, 02:58:50 PM

I have a new Pair of Pietta revolvers of the 1873 type. Because of an eccentricity on the face of one of the cylinders, it is necessary to surface the face of the cylinder. But, I can't get the cylinder bushings out of the cylinders on these pistols. They seem to be press fit.

Have any of you dealt with this successfully? I don't have a press, yet am hopeful there's some other way to get them moving.

Thanks for any experience you can share!!!

Coffinmaker · December 20, 2015, 05:56:02 PM

As long as you can turn them in the cylinder and they turn freely, you don't have a problem that affects function. For some reason, there is a "tight Spot" on a lot of Pietta SAs.

Simple fix. You need a bolt about the same size as the bushing on the star end. Then you set the cylinder on a block of some sort that has a recess (hole) the bushing can drop into. Set the bolt on the bushing, and tap it lightly to drive the bushing out of the cylinder.
Chuck the bushing up in a drill motor and polish it so it is a nice smooth slip fit. Oil it and put it back together.

Coffinmaker

Fox Creek Kid · December 21, 2015, 09:20:23 PM

Quote from: August on December 20, 2015, 02:58:50 PM...Because of an eccentricity on the face of one of the cylinders,...

And what would that be?

Coffinmaker · December 22, 2015, 11:36:56 AM

That would be a "high Spot." The "high spot" could tend to reduce the barrel to cylinder gap to unacceptable tolerance. Such as the cylinder stuck tight to the breach face of the barrel.

Or, conversely, a low spot. With an inverse effect on the function. The low spot could result in most of the cylinder face being "stuck" and a little space moving freely.

Or, just too much "run-out." That would make the cylinder face appear to "wobble" when spun at high speed.

Any of these conditions could well cause the inappropriate build up of gunk from BP, gumming up the works.

Coffinmaker

PS: Or have no real effect at all, other than to really "bug" the OP

August · December 23, 2015, 10:12:04 AM

Thanks, Coffinmaker, for your advice.

Yes, cylinder has a high spot -- relative to barrel. And, yes, the gun will run with new fangled powder, but gets balky with Gun Powder as this high spot collects fouling, which in turn causes interference.

I've had other Eyetalian pistols where the base pin was off-axis relative to the bore of the gun. But, that's not the case here. It is actually the machining of the face of the cylinder that is the problem.

Thanks again for your help.

p.s. still haven't gotten the bushings out, but have them soaking now in Kroil in anticipation of pounding on them.

Coffinmaker · December 23, 2015, 12:17:56 PM

There are two ways to eliminate the "high Spot." # 1 is to chuck the cylinder up in a lathe and turn down the high spot to the same relative plane as the rest of the cylinder face.
If you don't have a lathe, you will need a VERY flat surface. Cast iron table for a table saw, thick piece of float glass, precision ground lapping stone.
Squirt some 3M contact cement on the back of some 220 or 320 wet/dry. Put the contact on ONLY ONE SURFACE and stick it down on the flat surface. Run the cylinder face over the wet/dry, with most of the pressure on the high spot. When you have a consistent surface on
the cylinder face, polish the face with some 1000 grit. Re-blue is optional so song as you keep a little oil on the cylinder face.

Coffinmaker

August · December 24, 2015, 05:53:53 PM

Well, after soaking, I used an aluminum rod and gave it a good knock with the brass hammer. It came out reluctantly, but it only had to move about a quarter of an inch and it was free. After getting it out, I could see why it was stuck, in place. That's the way it was designed.

Thought I'd share a picture showing the peculiar radial machining and knurled end of the bushing. The knurling takes a good bite on the cylinder when the bushing is driven home. I can only surmise this is Pietta's notion of how one "adjusts" end shake on a SSA. Dumb!!!

I decided to leave the knurling in place and reassemble with the brass hammer. I'm not happy about it since I like to clean cylinders under running water after a match. I oiled everything well, but that won't last long.

Here's the picture of this strange bushing:

Coffinmaker · December 24, 2015, 08:14:46 PM

Congratulations. You got it out. Well done Padawan. Except ........

That Knurling is NOT how Pietta adjust End Shake. Pietta adjusts End Shake (if they bother) by surfacing the face of the bushing. Pietta parts are made on very accurate CNC machines. End Shake is usually within tolerance (+/- .002) without any attention. Normally, you'll find the bushing turns fairly freely when seated all the way into the cylinder. It is NOT to be left at all proud. Recoil will seat it anyway.
SO: Now that you have been successful in removing the bushing and putting it back in the cylinder, you have good practice.

NOW ....... TAKE IT BACK OUT!! Chuck the fat part up in a drill motor, wrap the end with the knurling with 400 wet/dry and polish it down until it slides nicely all the way in and out. That is how it should fit. Then, lightly polish the end you sanded with some 1000 grit, clean it off, lightly oil (Mobil 1) and THEN put it back together

Coffinmaker

PS: Not a strange bushing. It's the way Pietta Bushings look. They ALL need to be fixed. I don't know why they do that.

Coal Creek Griff · December 28, 2015, 06:58:01 PM

Thanks for your posts, Coffinmaker. I was actually dealing with this same situation myself. I used your instructions and fixed my bushing too. I appreciate it.

CC Griff

Pettifogger · December 28, 2015, 07:35:44 PM

Quote from: Coffinmaker on December 24, 2015, 08:14:46 PM
Congratulations. You got it out. Well done Padawan. Except ........

That Knurling is NOT how Pietta adjust End Shake. Pietta adjusts End Shake (if they bother) by surfacing the face of the bushing. Pietta parts are made on very accurate CNC machines. End Shake is usually within tolerance (+/- .002) without any attention. Normally, you'll find the bushing turns fairly freely when seated all the way into the cylinder. It is NOT to be left at all proud. Recoil will seat it anyway.
SO: Now that you have been successful in removing the bushing and putting it back in the cylinder, you have good practice.

NOW ....... TAKE IT BACK OUT!! Chuck the fat part up in a drill motor, wrap the end with the knurling with 400 wet/dry and polish it down until it slides nicely all the way in and out. That is how it should fit. Then, lightly polish the end you sanded with some 1000 grit, clean it off, lightly oil (Mobil 1) and THEN put it back together

Coffinmaker

PS: Not a strange bushing. It's the way Pietta Bushings look. They ALL need to be fixed. I don't know why they do that.

+1. That's not knurling. Pietta's QC on their SAA clones is usuallly excellent. This one slipped by. That's just sloppy machining. Polish it as Coffinmaker suggests and it will work like it is supposed to.