I've got the Pettifogger article too and it's well worth the paper to print out and read over a few times. Wondrous information for any of the generations of old Colts including the 1873. Some of the measurements might vary from gun to gun but his general practices on timing and tuning all of the Colt single action models.
All of those "tricks" with the pins and filling in the groove all help. Likely the pin helps most of all but a lot of shooters swear by filling in the notch in the face of the hammer too. I'm a touch embarrased to admit that I've not tried either yet. Too many other projects.
OK, here's another picture.
That split tube in the upper right is the jig I made up for holding the button in the lathe chuck so I could skim the thickness of the button until it was correct. It was turned from solid with a deep hole almost all the way through so the solid end acts as a pivot for the slit and only the front closes up. I should have machined a little relief for the rear half but in practice it didn't seem to be needed. It was one of those 2 minute projects of course. I'll tune it later for next time.
A set of feeler gauges gives you the ability to measure and know how much to take off. When doing this job I'd push the button against the cutter after each trial with a wire through the jaws so it contacted the cutter. The compound was set to axial so it was used to measure off the metal for removal. The last thou or two I took off by simply rubbing the flat side on a file with my thumb. the face for soldering was then given some shallow gooving so the solder was encouraged to flow more readily. Same with the nose of the arbor. A Dremel with a cutoff wheel was used for making these.
A good flux that you know works well with steel is required. Don't rely on the resin flux core of any electronics solder or the useless white paste sold in plumbing sections these days. If you can't find any of the old Kester paste flux that looks like honey coloured grease then see if you can find some Gryphon brand S-39 "Universal" flux. I swear it's good enough that I could solder cornflakes to Kleenex with that stuff ! ! ! ! !
I recently got some Slix Shot nipples for my Uberti Remington New Model Armies. But I was shooting just fine with the old stock nipples. Mind you there is no doubt that the after market nipples fit the caps a lot better. The stock nipples tend to have too much taper on them. Since you're metal savvy you COULD rig up some way of slightly reducing the taper by filing or maching off a skiff of metal lower on the nipple's side.
I don't have any Pietta C&B revolvers so I can't suggest a nipple size for you. But I'm sure someone will be along that has a Pietta and can suggest the size.
Here's a picture of one of the new front sights before shaping soldered on and another ready to be soldered on.
Before I started shaping the one you see soldered I cleaned up the excess solder with some old Dri Wick and a bit more heat. The sight was filed out with a medium fine cut round file so it formed curved sides. the top was then trimmed at the range only after a good couple of cylinders as I crept down on the final stroke or two.
This next picture shows what the rear sight looked like once done from the shooter's eye. Well, maybe not QUITE as the shooter sees it. Looking at this picture again the notch looks wider because the camera is between me and the sights.
I started off more narrow than you see and opened it up again at the range with another needle file that had the teeth removed from both edges and one face so I would only cut on the one side. The notch being opened carefully to maintain proper windage of my shots.
Aiming and shooting the three open top Colt replicas I've done in this way has been so much nicer than the old sights setup.
I was talking to a member on my range last week at MVRRC who was into BP and said he shot in some matches in the past! Can't recall his name, I will have to look him up too! Cheers Bob,,, edit, just noticed your post count, great caliber!
