Proper way to rechamber a revolver

[Nobade]

Here's something I've been contemplating but haven't done yet. How do most folks chamber revolver cylinders? The two ways I could see doing it are either on the mill with a rotary table, or in the lathe held in the 4 jaw chuck with a thin sleeve around the cylinder to keep from scratching it. I'd think the lathe is the way to go, since the workpiece will be spinning and it's easier to polish out the chambers. I'll just have to indicate in each hole in turn. On the mill it'd be easier since I just have to run the rotab around to line up each subsequent hole, but how would you polish the chambers other than with one of those ball hones? Anybody got any experience doing this? BTW, I'm thinking a new Vaquero would be fun in 38-40...(with a rebore of course.)

[John Traveler]

Rechambering a revolver can be a tricky proposition even if standard machine shop procedures are used.  I would not use a mill and indexing table or lathe to do this work.  It is all too easy to rechamber the cylinder incorrectly and end up with mis-indexed bore-to-throat alignment.

I've sucessfully rechambered revolver conversions using a mill or an accurate drill press as follows: 

1.  Turn or grind drill rod to a slip fit in existing chamber throats.  Use this guide rod to align and center chamber on mill table and clamp cylinder in position.  Check and recheck that cylinder is perpendicular to mill table.

2.  Use appropriate sized piloted reamers to enlarge the throat to final diameter.

3.  Ream to final chamber size.  This is done with extractor in place to correctly profile the cartridge rim seat.

4.   Polish the new chamber throat and walls using crocus cloth on a mandrel.

5.  Repeat steps 1 thru 4 for the other chambers.

Commercial factories have the special fixtures to manufacture cylinders, of course, as do specialty shops that do rechambering work.  Line boring fixtures and such are usually beyond the reach of home shops.  I've found that this method maintains reasonable chamber alignment with a minimum of special purpose fixtures and tools.

HTH
John

[gunnut69]

The 'Cowboys'  TV program recently profiled Hamilton Bowen(Sp...) and they used piloted tools to re-chamber.. They did have a flat plate with a holder of sorts but a prtty basic set up..

[jpcampbell]

I have done a few rechambering jobs and I make a fixture out of a 3/4 inch plate.
1) put 3/4 X3X3 plate on 3/4 inch parallels and mill top flat
2) drill a hole close to center of the plate for the base pin to fit into,just start with a small hole and use a adjustable reamer to open it to the right size,  a tight fit is necessary. You will notice that the front of the cylinder has a protrusion that fits into the front of the frame, the base pin goes through it,  countersink the depth and dia. of that protrusion so the cylinder sets flat onto the plate. It helps if it is a tight fit but it isn't necessary.
3) insert the base pin from underneath the plate, you may have to remove the plate from the vise to do it.
4) Place cylinder over base pin ratchet side up
5) using the correct size precision indicating pin in the mills collet indicate one of the cylinders chambers. just lift the mills quill up and down until the pin slides into the hole, I check it by putting dykem on the pin and pressing it into the chamber if its indicated correctly the dykem will be removed evenly from the pin.
6)  remove the cylinder from the base pin and remove the indicating pin and put in the correct size drill bit, drill a hole the diameter of the chambers smallest dia.1/2 inch deep, install another precision indicating pin into this hole, this will allow you to rotate the cylinder and have it indicated for each hole.
7) using the same precision indicating pin from step (5) indicate the chamber next to the one in step (6) , this will be the position you will use to do the boring and reaming, remove the indicating pin and put in the correct size drill bit.make the hole larger then the finished dia. of the new chambers size.
Now you bore the new chamber and ream it to finished size, you only need to pull the pin in step (6) and rotate the cylinder to the next chamber reinstall the indicating pin and your ready to do the next chamber. This works on all but the last chamber because the next indicating chamber will be to large for the indicating pin, you will have to use the indicating pin from step (5) to indicate the last chamber, just put it in the collet and rotate the cylinder until the pin drops into the last chamber then use a clamp to hold the cylinder in place, remove the pin from the collet and bore and ream the new chamber.
I would also recommend replacing the base pin with a new over sized one. the hole in the cylinders tend to go oblong with heavy use and the pins are known to bend, ream and replace the base pin before doing the chambers for a better job.  Use lots of lubricant and clean the reamers and chambers often while reaming and you won't need to polish them, it takes me about 3/4 of an hour to build the fixture, and 10 min. for each chamber, I use end mills when possible to rough cut the chambers and I have two adjustable reamers for the two sizes in each chamber.
I hope this helps I can see the process in my mind I'm just not very good at putting it into words.

[Nobade]

Thanks guys, that was exactly what I needed. I just couldn't come up with an elegant way to do it, and this would work really well. I appreciate it!