The 1860 grease groove on the Arbor, disappeared. Why ?

[Lefty Dude]

The original 1860 Colts have a grease groove cut on the Arbor. This is just behind the wedge slot. The rear of the groove lines up with the face of the cylinder.
The Clones do not have this groove.

Question, is why has it disappeared ? Maybe a cost savings ?

This came up with a discussion one of Pards and I had this past week. We were conversing about the 1860's. He has a pair of Pietta Army's. After a practice shoot he was cleaning his brace of revolvers and located a small line on the top of the Arbor, just to the rear of the wedge window. it looks like a scribe line, maybe a .001" or so deep. This also is in front of the cylinder face.

Last night we checked my Pietta 1851's. They also have the same line on the top of the Arbor.

I own a Belgium 1960NMA made in 1959, a first variation. On this piece we discovered the grease groove on the Arbor. This piece is as close to an original as they come. I assume the original 1860's also have this groove.

[Lefty Dude]

http://www.1960nma.org/Characteristics/Major%20Characteristics-13.05.11.htm

Scroll down to Arbors.

My piece is like the first variant shown.

[Mako]

Lefty Dude,
Ubertis have them:



But... they only make one arbor for the belt model frames.  So the groove lines up with the face of the 1851, 1861, etc., but the groove extends inside of the 1860 cylinder.  The 1860 cylinder is longer so it overlaps the groove a bit.  This groove prevented lead and fouling build up at the face of the cylinder/arbor which made it harder to rotate.  Some people call this a "grease" groove, but the grease is blown away with the first shot.

The line you are seeing is caused by gas etching fromthe cylinder gap.

~Mako

[will52100]

A side note, the walkers had a step down, or at least Uberti's did.  One of mine when I first got it wouldn't go three shots without binding up.  Turned out the step down was not quite far enough back.  A little work with a file and it'll go a whole match now.  The reason I figured it out was the small flame cut.  Most of my cap guns have a flame cut in them, but don't appear to be getting worse, including a 51 navy with over a 1000 rounds through it.