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When refinishing the cocking piece face, to remove any wear and polish it. Does it need to be hardened? Are these originally case hardened?
I assume that the sear is harder than the cocking piece as the wear between the two appears more obvious on the cocking piece face. So will redressing the face require further treatment?
We used to have a whole tray full of them reground at the correct angle at the machine shop but only so far. There was an inspectors gauge that measured the distance between the face and the safety stud. This dictated how far to grind but the whole cocking piece is hardened
Great, if the whole piece is hardened then it can be polished. Just need to keep the angles spot on.
I have made a system to help do it right without years of practice, posted on another site (different user name over there):
Refinishing the cocking piece face - Enfield-Rifles.com
They appear to be "differentially' hardened.
The "bents" at the front are VERY hard and the grasping bit with the hole for the striker seems distinctly less hard.
Messing around with the hardness is fraught with danger. I have a couple of No4 cocking pieces here that have obviously been "over-cooked" in the factory and subsequently fractured near the rear-most safety catch notch. At the point of fracture, the broken faces show a VERY large crystal grain size; not a good thing.
If you get the stoning / polishing of the full-cock bent (the front face) wrong, it will cause a lot of problems, some of them VERY dangerous. That front face MUST be perfectly flat and maintained at the correct angle; 86deg 10min from horizontal. Too close to 90deg and the trigger pull will be horrendously heavy, too much less and you risk the sear "floating" off and the action firing. Furthermore, that specific angle is designed to work with a (correct) sear so that if you take up the "first pressure" and then decide to NOT take the shot, the sear, driven by a GOOD spring, will rise back up the full bent to its "rest' position. If it does NOT do that, you will have a VERY dangerous condition on your hands; the action, if given a decent "bump" may well fire because the sear might just slip off the face of the cocking piece. ANOTHER good reason to get all of the dimensions, angles and spring tensions right.
Furthermore, if you get the angle right, but take too much off, you will break through the hard skin on a No1 Mk3 component and the sear will rapidly start indenting the face of the full bent.
But, WAIT! There's more! Removing too much from that face will also adversely affect the functioning of the safety catch / locking bolt because the "adjusted" cocking piece will be sitting a little bit further forward and thus, the various "safety" devices will NOT line up correctly.
As for "refinishing", Most steel components on the No1 rifle were originally "browned", i.e. essentially a SLOW "rust" blueing process.
Because of the differential heat treatment, the resultant surface is surprisingly resistant to "cold' blues and even "hot' ones like "Dulite", unless the surface is "activated", (the fine oxide skin resulting from the heat-treatment is removed).
I have not "refinished" any No1 cocking pieces, but the couple of No4 specimens I have had done simply required a LIGHT blast with VERY fine grit, (mask off the front face / full bent), and then they came out of the blueing tank almost black, with a non-reflective finish.
Bruce, thanks for your informative post. Useful information regarding the safety issues etc; it's always good to learn.
With regard to my rifles, they are only used for target shooting. I want to have a good trigger function, with a regular and clean release. The cocking piece "refinishing " mentioned is basically polishing out any marks left by the sear over the years. So intend to remove the absolute minimum to achieve a good finish. If there is any doubt about the functional safety after polishing, then I'll replace the part.
I was not intending to re-blue the part's, so maybe the title of my post is misleading!
Even if you are through the hardened surface I suspect you would get many years of service from well polished faces for the simple reason that they abrade each other far less than rough ones do. (Yes, I know the size of the contact area is a factor) The finest of the Japanese water stones produce an absolute mirror finish for example; not much wear happening if you have both surfaces that smooth, and bearing evenly of course.
If you have a lathe, a small vise mounted on the compound and a diamond wheel mounted on the spindle via chuck or collet chuck would get things flat and square for polishing.
Agreed that the amount of use it's going to get just shooting targets; it should last a good while. The rig I made for stoning by hand works well; it keeps the parts at the correct angle so the face is kept flat.
There are some photos of that on the link in an earlier post. Doing it by hand in the rig guarantee's you won't remove too much accidentally. The stone is a very fine Arkansas stone, with oil obviously.
Let's get our feet back on the ground here chaps........ In the real world of Armourers shops, we stoned the sear surfaces of these things all day, every day to set the pull-off weights and when setting up bolts. So long as you remember to keep the surface square and at the correct angle as stated by Bruce and are careful/workman-like you don't need to worry too much about failures. Just remember that you can deviate from the 'angle of attack' or the angular relationship between the sear and face of the C-P.....but.....! Any deviation will affect the pull-off weight to a greater extent than you thought possible.
Stoning C-P's was always by hand using the 'Stones, Armourers, tri-corner, flat. VAOS number B2/5345-99-961-7763. UP and DOWN and NOT across don't forget. No need for anything fancy in my world