A final patina finish for me. I'd prefer some color. 
I intended to see how the hammer and block pan out and maynjustnpolishnthem to white as traditionally found on the action originally. 

My pins are 4130 preHT. I can't touch them. So is my replacement breach face. I'm not sure if I should blue the breach face insert, leave white and let nature do it's thing and or blue the pins.

As for the screws, I am using Womack replacements. I'd like to case them as well but not sure of the metallurgy. Or should they just be rust blued.

I figure half the beauty of case color and I think any action that's not solid blue is the contrast provided by many parts of different states. 

Any suggestions as to how to finish the screws best? I don't want a rust bucket in 6 months. I DO want a good handling finish with some rust resistance on ALL parts.

Thanks in advance for any input. 

Oh one more question regarding my test parts. I have several trashed savage and stevens SS shotgun and model 24 o/u receivers. All seem to be built around ww2 era. 
I don't know what metallurgy these are and all references I did find we're unsubstantiated and not worthy. Are they alloy steel or mild? Were they indeed cyanide processed due to alloy? I'd like to use them as test fodder and yes they are trash but I'd still like to use them only if metallurgically it's warranted.

Mike

Screws can be nicely blued if held in molten lead for a short time.
They can also be bathed in molten salt peter aka niter bluing.

Salt peter can be bought where they sell meat curing supplies; as it is still used for that purpose.
Some drug store might still have it in small amounts.

Perhaps you assessment of professionals not quenching at high enough temps comes from their fear of the part warping at higher temps ????

Mike Hunter,

That's good stuff!! 
I figured that the receivers from savage and stevens were alloy and someone would stick a fork in them for me. Yes, no desire to attempt to case 4130/40, that's a no bueno.

Not being educated on manufacturer history, that is an eye opener on the early winchester receivers and absolutely makes complete sense.  Bingo, that absolutely gives a foundation for achieving color only and I know that can be done significantly under critical temp. 

The liability point makes good sense and works in combination with the above, color only aspect. If e restoration is for finish results only, then the lowest possible temp should be used to mitigate as best possible any problems with stress following quench.
Point well taken a Mike.

Mike I appreciate the direct answers. My company does some interesting work for bars and restaurants. I don't have a theif mentality so I have gotten an education from the purveyors on how folks steal money and booze in their establishments. There are basic ways, take bottle home, etc. then there is over pouring, increased breakage allowances, man there's a ton of ways to steal booze if your a bartender.
Not being a professional nor experienced, I don't contemplate all the fine points. You have made several very clear and they make fine sense.

I will argue the cumulative carbon in the steel. During annealing the martensite turns to austenite and the carbon is fully in solution in the iron. The carbon then leaves solution during cooling and creates perlite and ferrite Ina patchwork. The carbon lives outside of the iron molecule. When the steel is heated to temps very well below the critical temp while in annealed state, there is little carbon absorbtion since the. Iron never enters face cubic mode. Bottom line is nothing happens all at once, yes it is a progressive absorbtion and 100 percent occurs at critical temp with a lower yield below that temp.
But at 1100 degrees a very very thin case of martensite would be produced, like maybe as this as .0005 or .001. Continued.

There are so many variables when doing CCH to get predictable reliable results, changing just one variable can change the results considerably. 

Soak temp, quench temp, time at temps, water temp, wood to bone ratio, size of wood/bone char, drop distance from the water, how the part hits the water, drop distance thru the water, diffused o2 in the water, size of parts, thickness of parts, shielding etc… all play a part.

As an example,  parts allowed to soak at 1400 deg f, for 3 hours and quenched at 1100 deg f, into 45 deg  water, will have different hardness and colors than parts held and quenched at 1400 deg f, into water that’s 90deg f. 

Bubbles in the water serve two purposes: first, as pointed out earlier, it can add to the colors, but, there is a point of diminishing returns, as too much o2 will actually cause greying or lack of color. The second, and more important purpose is to keep the water moving around and thru the parts. When the parts are quenched into the water, the water directly in contact with the parts is immediately turned into steam. Steam will have different cooling characteristics than water. Steam pockets in and around the parts will cause uneven cooling, resulting in hard and soft spots, with significantly more warpage and cracking. The moving water helps prevent his. In the days of old, they used large amounts of flowing water; today, we find it easier to use air. 

Ingredients such as Potassium Nitrate, Salt (sodium chloride), Sodium Hydroxide etc., were sometimes added to change the cooling characteristics of the water. Many of these compounds made water wetter, i.e... increased their cooling capacity. Remember, cooling capacity is water’s ability to remove heat. Many folks don’t understand the relationship, and think oh pretty colors, I will add more stuff, then they get warped/cracked frames, or steel that’s as brittle as glass. 

Colors are formed at different temps, they are true “temper colors” much of it depends on the cooling rate of the steel. Adding shields changes the cooling rate for the shielded areas. And, just like with the steam pockets above, changing the rate of cooling has its consequences.   

Then of course there is the tempering phase, all parts going thru the case hardening process, need to be tempered. As with everything else, temps and time for tempering have measureable impacts on the end result.
 
I didn’t take any classes, pretty much self-taught; well sort of. I had a lot of help from a gentleman name

If you want to spend some time reading, Jim D. did an excellent treatise at the MFAC forum on his casehardening methods. There's about 31 pages of comments, but most is done in the first 15 pages or so.
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It's a really good read for anyone contemplating a start in casehardening. Lots of tips on temps, shielding, etc.

corerftech wrote on Apr 8^th, 2015 at 12:13am:


It's possible(?) that some of these things are being mixed up a bit, and possibly a different thing is happening. The relationship of the carbon to the iron may not mean that the carbon has left the case. If a casting or forging starts off with very low or no carbon, and is case hardened, the case is no longer as forged, but now a steel with enough carbon in it to harden. Chances are normal annealing will not remove that carbon.

Check your charts, if your goal is 30 Rc, the steel case may(?) be that hard in the annealed state, as chances are, a quench from above critical may approach a hardness around double that amount. Maybe another reason there isn't a need to quench from above critical depending on the hardness goal. Another quick thought, if you get full quench hardness, and temper at high enough heat to bring it back to 30 Rc, your colors may not survive.

But, agreed, the colors are where it's at. Only thoughts is all.

I used an eyeballed 2.5 or 3:1 wood/bone mix. I did preheat the mix in my kitchen overn at 250 for 30 mins to drive off moisture. The wood char had all been through one anneal cycle already.

Please ignore all the dings, pits, scratches, etc. This receiver was junk when I got it in a box of JUNK receivers that were all parted out. This was rusted beat to hell trash when I started all polishing by hand to 600 grit. I have never blued a gun and as for the swirls I left in the 600 grit, was worried Id see them in the finish. Not a chance. Pits, crap, yes. Swirls at 600 grit, the finish is magnificent. As magnificent as a gravel road could be. No filing was done. I did use brownells rust/blue remover to clean up all the gouges to the core.

Boy pits really show up. The receiver has millions of fine pits, well not so fine that 80 grit wont take them away. They are super fine following the polish. You cant see them w/o having the light strike correctly and the camera perceives them far better than my eye, but they are there. the whole flank is dotted with white reflections like little tiny STARS shining.

The raw wet oil also makes the finish look dull, when its really not. Strange. It looks much better, less drab, when there is less oil (not no oil, just not the WET look). Its like lint and oil combine to form DULL.

Anyway on with the pics. Fresh out of the drawing oven at 350F /1 hour. Eds red applied and soaking in. LED overhead lighting in my kitchen. Ipad for a camera.

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