Anyone mill, turn or burn a Ruger BH cylinder?

[kywoodwrkr]

Has anyone taken the time to create a new BH cylinder from scratch?
I've got some 4140 round stock and need some cylinders and was wondering if I should attempt this.
Have access to CNC mills and lathes as well as a wire EDM.
Also cylindrical grinding machine-as yet untested by me.
So far have drawn up cylinder in MasterCam Mill and Lathe.
Have drilled pilot holes for wire EDM.
My thought are to using the seven pilot holes, burn on the EDM and grind to diameter on cylindrical grinder.
Finish ends in lathe milling ratchet on horizontal mill.
Instructors have suggested sinker EDM for the ratchet.
Anyone have experience in this endeavor?
Thanks.

[Dark Helmet]

Ask Lee http://singleactions.com/

[leftiye]

Before you go for it, be sure that your 4140 is good enough steel for the purpose. I've heard that there is a difference in quality when it comes to using it on gun barrels. If you want to correspond on the cylinders PM me it's been a long term project of mine that's been on a shelf for a while.

Heat treat to Rc 45 it will give you 210,000 psi tensile strength (approx.). The star on the back of the cylinder can be cut with a 60 degree dovetail cutter in a rotary table. The rotary table needs to be bolted to a stand with a dual 30 degree offset (one lengthwise, and one to the side. The stop detents can be set at sixty degrees and cut, but the relation between them and the star faces must be figured and set before the star is cut. Chamber bores can be started (located) to cut in the frame with a drill guide in the barrel threads of the frame (and the cylinder clamped in place for each chamber), and finished in a vise on a mill with a centering scope. One might want to finish at least the chambers, and chamber mouths after heat treating. If heat treated in a stainless foil in an atmosphere controlled furnace, the scale is minimal, and may not even be necessary or desired to remove (including where the star and detents are concerned). I've used it as a finish on falling block muzzleloders that I made.

[bohica2xo]

4140 is not the best choice for a cylinder, and heat treating to 210ksi will make it too brittle for that application.

An oil quench on 4140 with a 2 inch section will leave you with a soft core anyway.

If you are making a Blackhawk cylinder in a mild caliber, I would be inclined to drill 70% of the diameter through all seven holes - then heat treat to 28 Rc.

After heat treat, you can finish the bores on the wire, and hold .000025 if you take your time. You can allow a bit of material for a trip to the hone if you want.

Once the bores are in it with perfect indexing & alignment, a chamber reamer will finish things up quickly.

Plenty of ways to cut the ratchet, but the sinker is always more fun. The cylinder stop notch requires some care. It should index the chamber to the center of the bore on the frame you are using. The sinker is good for this too. Cut one notch about .010 deep, and check your work with the frame & the cylinder stop before proceeding.

If you are not married to that 4140, replace it with some 4340, or 13-8MO (or A286, 17-4PH, 300M...)

B.

[John Taylor]

Why not start with one of these http://www.brownells.com/.aspx/pid=21081/Product/RUGER_reg__SA_REPLACEMENT_CYLINDER_BLANKS
I have made cylinders for the cap and ball conversions and am in the proses of making a cylinder for an 1877 Colt. Never had a need to make one for the Ruger. I have been using heat treated 4140 that comes in at about 32 Rockwell C. This is the same hardness of Douglas barrels. Talking to some of the other barrel makers it seems most are going with a hardness of 28 C. Seems they would rather have one bulge instead of break.
I made up a reaming fixture to help line up the chambers to the bore by making a dummy barrel and running the reamer through it. This is after the star and bolt cuts were done. With the bolt locked in place the reamer would insure that the cylinder was lined up to the barrel.
http://i95.photobucket.com/albums/l132/johnptaylor/reamingcylinder.jpg