Why arent molds made from stainless steel???

[mikenbarb]

I am wondering if anyone has ever made stainless steel boolit molds? I am thinking this may be the best material for them due to the rust factor and you would never need to worry about it again. I know alot of you are thinking because of price but that cant be the case because stainless isnt that much more than the material they use and even if it was it would be well worth a few extra dollars to have a mold that would never rust.:confused:

[Harry]

I'm not a metalugist or engineer, but when working in construction of power plants, we used almost all stainless steel tubing. The coefficient of expansion of stainless is pretty large, meaning it expands quite a bit with increase in temp. I would think a mold of stainless would have problems with expansion, and possibly uneven expansion. Just a thought.

[Papa Foxtrot]

Stainless is also a poor conductor of heat. It would prob'ly be difficult to get the mold to optimum temp and keep it there.

Papa

[mooman76]

I do believe it doesn't tool well or as easy either, but don't know for sure.

[oneokie]

Stainless does not finish well. (smooth surface)

[jhrosier]

Stainless steel is very challenging to cut under ideal conditions.
It work hardens badly with light cuts.
The light feedrate needed to cherry cut a mould would toast a good cutter in moments.
Even a much more expensive carbide cutter would not fare well under these conditions.
OTOH, the same cutter, when used on brass, aluminum, or cast iron moulds could be used to finish dozens of moulds with very little wear.

I do CNC programming and deal with this problem every day.

I think that iron moulds are a pretty good material for the job and won't rust if given just the minimum care, either by oiling or storing in an airtight container witha bit of vapor barrier paper.

Jack

[briang]

I'm not a metalugist or engineer, but when working in construction of power plants, we used almost all stainless steel tubing. The coefficient of expansion of stainless is pretty large, meaning it expands quite a bit with increase in temp. I would think a mold of stainless would have problems with expansion, and possibly uneven expansion. Just a thought.

Very true, I plasma cut stainless plate for a living. I've had some very large parts shrink as much as 1/4" after cooling. It also warps badly when heated from one side.

[shotman]

If you have a SS hand gun like a 629 fire about 3 cyl fast and then see what kind up group you get. I would think the mold would have a good size varity. Like said is hard to work the way a mold is cut.

[JIMinPHX]

In addition to being hard to machine, most stainless is also prone to metal fatigue from heating & cooling too many times. Oh yea, most of it warps easily too.

It is possible to get good finishes on stainless, but you need very rigid tooling, very positive clearance angles & lots of the right kind of lube. You really need to watch your feed rates, surface speeds & tool tip geometry. It's not quite as bad as working with Hastiloy or Ti, but it ain't nothin like aluminum or leadloy.

There are a few alloys that are slightly more friendly than most of the others. 303 might be a possibility. I'd have to check & see if hot lead sticks to it though.

[mikenbarb]

I truly dont think distortion would be a problem because were talking about a think block and not a small thin piece that would distort easy. Most stainless is made for high heat applications where mild steel wont hold up. I have worked with SS for years and theres lots of different alloys available and some are quite soft and machine excellent even under close tolerances but I guess even the softest SS is still too hard for the cutters they use. It could also be the micro structure of the metal as it would have a change of composition as its heated and cooled numerous times and would eventually become soft like mild steel. It would be nice if someone did try it to see what the outcome would be and how they hold up. Im even thinking a Hardox material may work good also with proper tooling. Its hard and holds up to the elements better but still machines nice.

[deltaenterprizes]

Brass has the corosion resistance of stainless steel and machines much better.Very few people are willing to pay the cost of a brass mold, do you think many would pay the cost of a stainless mold?
If you want a stainless mold I am sure that you could find someone to lathe bore one for around $500 to $1000, how many do you want?

[mikenbarb]

LOL, Not many at that price. I guess Lee has the right idea with aluminum ones.

[lathesmith]

As I see it, SS really gives no advantages for a bullet mold over aluminum. It's much harder to machine, and would wear out tooling faster--all factors that would raise the price of even a "simple" mold into the stratosphere.
lathesmith

[Russel Nash]

tin foil hat mode on....

also, methinks that there is a bit of planned obsolesence to it all also... if I sold you the perfect mould that never rusted and could stay its shape and size for maybe 10 bucks more than the iron moulds... well, I could never sell you a replacement, now could I?

I only say this because supposedly Thomas Edison still has light bulbs at his place that he made way back when that are still glowing brightly.

and then throw a few other things into the mix... people are cheap... even though most of us here would consider ourselves afficianados or coneissuers of casting equipment most people would stop and think:


Hey, I could buy 3 or 4 Lee aluminum moulds for the price of one X brand stainless steel mould. Heck, the Lee moulds are good enough.

so such a company wouldn't... couldn't be competitive and stay afloat for very long.

I'm still kinda new to this casting thing.... SOOOOO... I have to wonder why did H and G go under or did they get bought out?

It sounds like everybody here ooohhhss and aaaahhhss about their moulds.

[Linstrum]

I'll throw in my 2 cents to the kitty here, what the others have said about stainless is quite true. Of all the stainless steel family alloys I have worked with since about 1959 when I began working as a machinist apprentice, type 303 - either 303S or 303Se - would be my choice for a stainless steel mould since it is what I have found to be the easiest to work with. The problem with that alloy is stress corrosion when repeatedly cycled to high heat, but under ~900°F it would take a long time for changes to cause a dimensional problem, if it even ever did. Types 321 and 347 are not bothered by heat - they were designed to exist in a red-hot environment - but their machinability is pretty poor in comparison to type 303.

The mechanical requirements of a mould are not great when compared to something like a gear or bolt cutter where rather enormous spot stresses are encountered. All a mould has to do is remain dimensionally unchanged when the sprue cutter is used, and those forces are not great when compared to something like a bolt cutter - as we know (or should!) boolit alloy is very soft in comparison to something like a 1018 mild carbon steel bar and the shearing forces to cut off a sprue are a butterfly sneeze compared to shearing even a 16d common nail.

If toughness, machinability, corrosion resistance, and dimensional stability through thousands of heating-cooling cycles are all that are wanted in a mould, then Alcamax aluminum alloy, which is the material of choice for gasoline and diesel engine pistons, would be my choice for mould-making. I have made dozens of moulds over the last 45 years but I have never actually used Alcamax since I have had good results using whatever grades of aluminum are used for extruded bar.


rl510

[hammerhead357]

Russel Nash, H & G sold out. I used to do business with Wayne Gibbs years ago and Wayne was getting close to retirement age and sold out. I think there may be a little more to the story but it is late and I am tired so can't remember all of the details.
H & G made the best moulds available as far as alot of people are concerned, myself included. At one time or another I have tried out a lot of different makers moulds and the H & G moulds were the best I ever used .They were available in up to 8 or 10 cavities at one time.
I still have about 16 or 18 of them and at one time I had about double that number but exwife got half of them in divorce. ******all........Wes

[mtgrs737]

Why not just nickle plate Iron moulds to make them corrosion resistant? One member here does this himself and he says that the plating is so thin his boolits are only reduced by .0001" (one ten thousandth of an inch) in diameter. Has anyone else had any experiance with nickle plating iron moulds?

[deltaenterprizes]

I read H & G sold out because of the increase of the cost to renew their insurance policy.

Hammerhead:

Does she cast a lot of bullets with those molds?

[EchoSixMike]

Why mechanically cut the mold, why not EDM the cavities? S/F....Ken M

[JIMinPHX]

Why mechanically cut the mold, why not EDM the cavities? S/F....Ken M

I take it that you've never used an EDM machine before?

A wire EDM simply would not be able to produce the shapes needed. A plunge type EDM would take a long time to cut a cavity even of you tooled it up properly to do the job. Making the necessary electrode would be a nice little pain in the butt too. If you did manage to get that far, the surface finish that you ended up with would not be acceptable anyway. You would need to do a bunch of finish work after the EDM. It's just not a good application for that particular tool.

[jhrosier]

.... If you did manage to get that far, the surface finish that you ended up with would not be acceptable anyway. ....l.

Hmmm,
A 'textured' boolit. Bet that would hold a bunch of LLA, if you could get it out of the mould.[smilie=l:

Jack

[EchoSixMike]

I take it that you've never used an EDM machine before?
A wire EDM simply would not be able to produce the shapes needed. A plunge type EDM would take a long time to cut a cavity even of you tooled it up properly to do the job. Making the necessary electrode would be a nice little pain in the butt too. If you did manage to get that far, the surface finish that you ended up with would not be acceptable anyway. You would need to do a bunch of finish work after the EDM. It's just not a good application for that particular tool.

Correct, I'm passingly familiar with the product, not the process, so I thought I'd ask. A mold maker(general industry, not boolit molds) friend of mine has mentioned EDM'ing molds in the past, however I was unsure of the application for those molds. I'm fairly sure there's a reason why they don't EDM boolit molds, but didn't know whether it's a physical limit or a financial limit. Thanks for the info. S/F.....Ken M

[TAWILDCATT]

I have a winchester mold in 32/20.I got it before WW2 it came with a tong tool and win73.I got the tools I could not get the gun.that mold is perfect.no rust.and
handles are part of mold.so how long do you want them to last?It was made some time after 1873.to go with the gun.:coffeecom [smilie=1:

[mainiac]

Ive welded much.much stainless, both pipe and structural. SS is evil stuff,because of the warping. welding it,you need to know how much heat you can get away with, and you have to stagger around the weldment,,,,, and the damn stuff will still pull! IMO, cant amagine a ss mold would be the way to go.

[badgeredd]

Just a couple things to add. SS has high chromium and high nickel content in most grades. POOR heat dissipation. So once one got the mold to temp (and that would take a while), one would have more trouble con tolling the process due to it wanting to hold the excess heat.

Second, the EDM process on a CNC EDM machine IS feasible BUT and this is a big one, the machine time would far exceed the cutting time using the current process. Therefore it isn't really practical from a manufacturing standpoint. As for finish, well the newest CNC EDM machines can burn a finish finer than can be cut with conventional tooling. BUT it takes time, and again a big limiter for a manufacturer. Electrodes can be produced on CNC lathes that rival any ground cutter, but again the time constraints kill it.

Most free machining SS has high nickel and reduced chromium, but I imagine the heat dissipation thing would be a biggie here too.

I'd have to wonder how plating would affect heat dissipation also. I know it does have its problems in the plastics industry with some resins because of the high thermo coefficient.

Not to say stainless isn't used in the plastics industry, but it is pretty much limited to medical and aerospace applications, due to cost and time required to work with it.

Just based on my experience as a tool maker and and in the plastics industry for quite (far too many) a few years.

Edd

[felix]

Edd, you got it backwards. For machining you want the chrome to be around 12 percent, but close to if not zero nickel. Sulphur must be added to make cleaner cuts, however. ... felix

[EDG]

Ive welded much.much stainless, both pipe and structural. SS is evil stuff,because of the warping. welding it,you need to know how much heat you can get away with, and you have to stagger around the weldment,,,,, and the damn stuff will still pull! IMO, cant amagine a ss mold would be the way to go.

Yeah welding a lot of things is a PIA.
However machining 18-2 FM stainless steel is like cutting butter and is not susceptible to stress corrosion cracking. The greatest technical impediment to using stainless steel in bullet molds might be galling of the sprue plate against the blocks. However that can be handled by using Nitronic 60 which is extremely resistant to galling. (BTW never ever use 17-4 PH stainless for sliding contact against itself under any load. It is the classic gall-o-matic.)
There is also the great load of conservative inertia in the shooting sports. It took choke tubes about 40 years to reach full adoption due to the bone heads that market shotguns.
I suspect that few bullet molds see any real use (other than cast boolits members) and aluminum will eventually snuff out the iron and steel molds.