Steel grade for making nipples

[Oyvind]

Can anyone tell me which stainless steel grade is best suited for making percussion nipples for rifle muskets? Will, for example, 303 SS be too soft?

[Acer Saccharum]

I'd think you'd want a heat treatable steel, one that can be hardened and tempered. 303 and 304 are pretty malleable, which means they would mushroom in short order.

maybe a heat treatable alloy like 410 or 440C? I have no experience with either of these.


an alternative might be to fit a SS or platinum orifice in an alloy steel nipple for extreme durability of the flash hole.

[Steve-In]

Check out 17-4 PH.  It machines fairly decent and if I remember right it is around 30 RC as purchased.  I do not know if it can be made harder.  You will need good sharp tools.  It is what many choke tubes are made from. 

[Pennsylvania Dutchman]

17-4PH heated to 900 F and air quenched will be RC 44-46  when cooled. It is also very stable in heat treating. To be able to harden it you need to ask for solution treated material and it will be about RC 38-42 as purchased. Mark Poley

[Dphariss]

Can anyone tell me which stainless steel grade is best suited for making percussion nipples for rifle muskets? Will, for example, 303 SS be too soft?

If I were you I would consult a metallurgist.

Dan

[Oyvind]

The average metallurgist probably knows nothing about percussion nipples anyway, so I was hoping there was someone with nipple making experience here. I know nothing about metal (except for the music genre), but I having a batch of nipples made by a CNC machinist for an old Norwegian rifle with odd nipple threads. I guess it would be easier for him not having to harden the nipples. One suggestion I've got elsewhere is 310 SS.

[T*O*F]

Oyvind,
Glad to see you are still around.  It's been many years since we've been in contact.  If you will send me an email, I will provide you with the contact information for the guy who makes nipples for long range muzzle loaders.

Vanha kettu

[Acer Saccharum]

That's the great thing about this forum. The collective resource and knowledge base is very deep. Thanks, Dave.

[LRB]

  There are at least two metallurgists on this forum that would probably know. James Kelly and Jim Kibler.

[Acer Saccharum]

In my limited experience with stainless alloys, corrosion resistance goes down as hardenability increases. 

One alloy, 304 is marvelously corrosion resistant, but is not heat treatable. It work hardens and will mushroom, eventually fracture.

The more steel the alloy has in it, the better it can be heat treated, but it compromises its corrosion resistance. (and erosion resistance)

The old timers had the practice of platinum lined nipples for percussion (and platinum or gold lined vents for flint).

[shortbarrel]

I make them out of drill rod. I make them and harden to a cherry red, polish and temper to a dark blue. Never had any trouble with one.They will shoot hundreds of rounds and they are kind of like the old nipples. Every gun I ever built has one on it.

[JCKelly]

I like Shortbarrel's approach.

For high pressure loads, as in shooting elongated bullets rather than round ball, the best I know of is to find someone who will line a nipple - perhaps one of Shortbarrel's - with platinum.

If you like 17-4PH, which seems reasonable to me, you might want to machine it and then heat treat it (age it) 4 hours at 1000 to 1050F. The 900F treated stuff is a bit brittle.

If your concern is the flash hole eroding, because you use 500 grain .45 cal bullets, then 310 (25%chromium 20% nickel) has perhaps the best hot gas erosion resistance of anything you are likely to find. 309 is next, 23%chromium 13%nickel. It is chromium, mostly, that gives hot gas erosion resistance.

I personally do not know where one buys small quantities of 310 bar. The next step down is 309 stainless (heat resistant alloy) which you can buy, along with 17-4PH, from www.mcmaster.com.  309 is a $#*! of a lot better for flash-hole erosion resistance than are any of the stainless nipples stocked by suppliers. 17-4PH also available from www.onlinemetals.com.  I would not use 440C, too brittle & no fun to heat treat.

The only use for 303 is to use on an automatic screw machine, otherwise the properties are unimpressive.

[44-henry]

Something like D2 may work. It isn't exactly stainless, but it is a high carbon steel that does have a high chromium content which makes it very resistant to corrosion. It has the added advantage of being tougher than most stainless steels. I have made a few knives with it and have found it to be excellent for that purpose. Heat treatment is a pain if you do not have a furnace with accurate temperature control.

[flehto]

Hyvää Päivää "vanha kettu" {Old Fox}....oletteko Suomalainen? . Minun nimini on Fred Lehto ja minä olen Amerikalais-Suomalainen. ....Tervesiin....Fred

[T*O*F]

Hyvää Päivää "vanha kettu" {Old Fox}....oletteko Suomalainen? . Minun nimini on Fred Lehto ja minä olen Amerikalais-Suomalainen. ....Tervesiin....Fred

No Fred.  I'm not Finnish.  TOF is short for This Old Fox and friends from Oyvind's part of the world called me Vanha Kettu.

[Oyvind]

Thanks for you replies, much appreciated. I think I'm starting to get the picture. TOF's man by the way used oil hardening tool steel which was hardened by hand with a torch.

As for Finnish, that must be the most complicated language in the world. Norwegians, Swedes and Danes have no problem understanding each other, but Finnish not possible for us to understand at all. Its like understanding what metal to use for nipples