A different mould material question

[Gunslinger1911]

A buddy at work with machining experience (edm) asked me about stainless steel as a mould material. I have never seen or heard of a SS mould.

I figured someone here would be able to enlighten me.

What say you mould masters ?

[theperfessor]

Most grades of stainless steel are a real pig to machine. They also have a higher expansion coefficient, and are more prone to warping from unequal heat distribution. Given the temperatures lead alloys cast at and the non-abrasive nature of lead alloys, stainless steel offers no real advantages over cheaper and easier to machine materials.

My opinion: Can you do it? Sure. Does make any sense economically or in the quality of the bullets you get out of it? No.

[Bret4207]

I think there have been a few posts on using SS in the past here, and they all say pretty much what Prof Keith said. Machining is the really hard part I understand.

You want the perfect material? Brass is pretty hard to beat IMO.

[Gunslinger1911]

WOW - less than 15 min reply !!! THATS what I like about this site !!!

thanks Perfessor, and Bret

[cajun shooter]

I would think because of the hardness that if using the cherry method your price of production would be very high and the speed at which you could cast would lose a molasses race.

[MBTcustom]

The only SS I would consider making a mold out of in 416. Its easy to machine, is a very stable material, and does not warp with heat near as bad as all the other SS I have worked with. If you are talking about making a mold out of 300 series SS I would say that is a tricky deal. You will have a real fun time machining the cavities, (even wit a CNC lathe) and you will have issues with heat warpage. But, If he is willing and curious, go ahead and do it and post your results. I never would have recommended brass as a mold material, but here I am, casting away with one!

[beagle]

I've used SS sprue plates and they work good but again, they're not hard to machine as moulds are./beagle

[Gunslinger1911]

Great info guys, thanks.
My buddy has a history in edm - don't know if it would work or not, it's as much "what if ? " as anything.

I'll let you know if anything comes of it.

[turbo1889]

I knew an older gentleman who has since passed on who was a wood-worker/cabinet-maker by trade (the fine wood works) and his son became a machinist and he ended up getting into it as well and get himself one of those 3-in-1 combo machines and did end up making his own molds eventually. He considered the Lee 6-cav molds with their cam lever sprue plates to be a superior design made with inferior materials and made his own version from SS that had taller blocks that would take both pistol and longer rifle boolit designs.

I have a couple of the molds he made I bought when his kids sold off his stuff after he passed on. I know they are some kind of 400 series SS but I don't know which one exactly. He did cut cooling fins above and below the handle slots in some of the blocks with larger boolit designs in them so the sides of the mold blocks look like the sides of an air cooled engine cylinder which keeps the molds from running too hot.

So it can be done but the only example I know of were done by a guy who was obsessed with quality of materials that he carried with him from his wood-worker/cabinet-maker trade into his machining hobby in his retirement and as I said it appears he used a very specific grade of stainless steel and the blocks and the sprue plate are not made of the same exact steel but both are different stainless steels. I do know that his alignment pins are made from cobalt drill bit shafts reground to form male and female alignment pins and the bolts for the handles and sprue plate hold down are stainless hardware.

It can be done but I'm not sure it could be done commercially and still compete with other alternatives like brass mold blocks with stainless sprue plates and hardware which is an excellent combination. I especially think the cobalt drill stock alignment pins are "over the top" but if you are making your own you can go as far out there as you want too I suppose.

[Gunslinger1911]

This is great stuff !

My buddy is just getting into reloading and casting (I've been doing both for 35 years). He has a background in precision machining / tool & die. He's asking questions about things I haven't thought about in decades - kind of refreshing ! I gotta get him in here !!

[Nobade]

I tried making a push-out mould from 416. (Actually a chunk of barrel) It never worked very well, by the time I got it hot enough to throw nice boolits they would start sticking in the cavities.

Two things I think would make a good mould but have never tried are soapstone and graphite.

[Cap'n Morgan]

I especially think the cobalt drill stock alignment pins are "over the top" but if you are making your own you can go as far out there as you want too I suppose.

Not only "over the top", but way down the other side...:bigsmyl2: