The Home Machinist!

Hi Hammermill, When I say case hardening it`s just that and not colour case, it comes out a light grey colour. I think Shilo Sharps are the only ones that do it on 4140 steel and that's what I`ve got so will have to be blued. I may try and acid etch some bison on the lock plate after some experimenting, but will have to look around to see where you get the pitchers of them. Now that I can fit all the parts together, this is where you find out what's not working and the firing pin strike is to high, the under lever needs bending up a bit so the breech block is a bit lower. Have just about got the barrel fitting nicely, with a flat on top the breech block is a tight sliding fit on the barrel breech face, a bit of fine sanding should fix that and still be a o head spacing, but this will wear in over time. There is a 15"thou gap where the barrel screws into the receiver, so will have to make a round shim of about 16.5" thou for a tight crush fit, once its fitted that's it, it`s on for good. That would you put on the barrel threads, thinking of graphite powder only so nothing will muck up the blueing, there`s lots I don`t know in this game. Homebrew.357.

I would assemble with a coat of lead plate or copper coat. sparsely applied.
how are you planning on bluing, with hot salts or a cold process. I have a appreciation for the slow blue process where the steel is hung in a cabinet with a high humidity, the finish applied and allowed to sit until carded off and reapplied. not a fast process, but you will be busy with the stock oil rubbing process. hihi both provide deep luxurious looks

Hi Hammermill and all those watching, I gave it a check over and loaded some cases with primers only to see if they would go bang! and they did, so I have lift off with this Quigley down under 1874 Sharps in 45-70, , I don`t believe it, never thought I would get this far. A few more jobs to do, like cutting the slot for the case ejector and fitting it and then will get it case hardened, final polish and clean up with some etching. Will be sending it to a plating shop for the hot blueing job, save me stuffing it up and then will be into making the stock. It`s getting there. Homebrew.357.

Hi Guys, I put my thinking cap on to figure out how to cut the slot for the ejector in the receiver and came up with the idea of using my lathe as a shaper. So made up a T/C cutter from a saw blade and set it up in the fore jaw chuck, then mounted the receiver on the cross slide at the right angle and height, then using the saddle up and down, in feed with cross slide I slowly cut the slot. As the cutter was a bit smaller than the required slot size I just reset it to finish for the finial cuts. A bit of filing, sanding work and now the ejector fits in nicely. The next bit will be milling the breech end of the barrel so the ejector sets in when the breech is closed. , Hek, I should put this out in a novel, Cheers, Homebrew.357.

Back again, having got the ejector working in the receiver I had to mill a flat and a slot in the breech end of the barrel so the ejector has some where to sit when breech block is closed. Mounting the barrel on to the cross slide at right height and angle and milling cutter in four jaw chuck I got the job done. Then a small cross slot behind the case rim finished it off. It`s all coming to gather guys and soon will be sending the receiver and breech block for case hardening , with that done I can fit the barrel permanently to the receiver and then a proof test . But you will have wait a bit, as my wife and I are going on a three months holiday in our caravan to the south Island of NZ, as they say , "Don't leave home till you have seen the country". , Cheers, and have a good Xmas, Hombrew.357.

Hi, Now I had the barrel done it was time to see if all my milling would work. So assembling the barrel into the receiver I tried a case, closed the breech and opened it, "ping", out popped the case !, so that's all up and working. I have been making a tang sight for the Sharps just to get it so I can shoot it, and at a later date I will try and make a better one. Having drilled and taped two holes for the sight I can now send the receiver and breech block out to be case hardened and while that's going on I will mill the dove tail for the front and back sights, then I can assemble the barrel to the receiver nice and tight ready for proof testing . The next thing will be making the stock, but as we are going to have our big O E of the south Island of N Z for three months in the new year, you will have wait for more updates . Cheers, Homebrew.357.

I imagine that you are aware, but case hardening will affect tolerances.

Threaded holes will close up etc., so if things are nicely fit now, they may not go back together after case hardening!

Hi GlennW, Thanks for your reply, I was told this by the heat treatment guys to, it has only .001/2" tolerance, so could really be a problem and grinding to make things fit will wear off the case as well. As the receiver is 4140 steel and the breech block is 1045 steel , what would be the best way to go, leave it as it is, just make sure it`s well oiled. As the case was only to stop wear and will not make it stronger,(I think), do I need it. This shows I`m not a machinist and there`s a lot I do not know, Thanks for any help on this Cheers, Homebrew.357.

You might look into Nitriding.

I'm not real familiar with Case Hardening as I have only done a limited amount of parts that were ground to final size after.after.The only way I know of to minimize bore distortion is to leave any threaded holes or bores out until the part is Carburized. The you can bore, drill, and thread as required. Then send it back for heat treating. This way the holes will not be carbon enriched and will not case and can be finish sized or threaded as a final operation. The trick is to chamfer the edges of the holes to just below the Carburizing depth so the entrance to the hole does not case harden.

There may be other methods of actually masking the Carburization process in certain areas though, but you would have to ask the heat treaters about that.

I have a friend that does quite a bit of Nitriding and from what I understand, and if done properly, there is no distortion or dimensional change.

As I recall though, you were wanting color case hardening.

That's all I know!

I should also mention that this is the best thread on the Internet!!

What you have done is phenomenal!

Here is a form of Black Nitriding.

https://www.youtube.com/watch?v=8QjbOZAx2mw

Hi again, It`s probably the way I`m saying this, yes I would love to have it "colour case hardened ", but can not get it done in NZ and being 4140 only Shilo Sharps does this on high carbon steel. So when I say case hardening it is nitriding, case nitriding?, the heat treatment shop says it comes out a grey colour and can be black oxide after this is done, so I think the best way to go would be to take the parts to the heat treatment shop for them to see and what they say just to make sure things don't get stuffed up. I have emailed them and said what I had and they said the barrel is ok as is, the receiver and b/block would be best nitriding them as there is less distortion. So will take it to the guys that know and get it checked out before I do anything. , Homebrew.357.