What is ``good'' ``tool-steel''?

May 24, 2004 12 Replies

Hi all,



So, I've got some tools in mind I'd like to make. All indexable carbide-insert type stuff. Possibly some end-mills, some shell-mills, some side-milling cutters, boring bars, etc., etc... So, what makes a particular ``tool-steel'' a ``good'' choice for such stuff? Here are some properties I'd like:



Minimal on the rust over the years. I've got some tools made back in the 40's that don't seem to have any rust on them. I've got this old milling machine that was made around the same time and most surfaces (including the ones I could tell were just completely neglected for many, many years when I got it) don't seem to have any real rust on them. Just sort of a ``patina'' on them. What kind of material is this stuff? I can't believe they used any kind of stainless...



Stands up to abuse. If the tool is dropped, I'd like not to have to throw the thing away 'cause it's got a dimple in it that throws all the tolerances out. OK, so maybe have to throw away the one insert that took all the shock, but so be it. I don't want the stuff to get all bent out of shape 'cause some bone-head takes a cut that was too heavy, or worse yet, has a minor crash with the tool. I don't want a tapped hole to strip 'cause some ape hunkered a screw down too tight. You know, general abuse. Stuff that shouldn't be allowed to happen, but sooner or later usually does...



Light on the special processes. I'd like to avoid heat-treatment, grinding and all that, if at all possible. I've got a mill and a lathe, and I'd like to stick with just those as long as I can.



Machinable. More's better, of course, but hey, given my other constraints, I'll take what I can get.



So, am I living in dreamy-land? Does anything fit the bill for at least most of the above? Anyone have any other properties I've missed? Anyone have a supplier in mind for whatever stuff they like? Of course, cost is a factor, but only after a certain point. I probably don't care that much about the cost, within some window. I'd rather make some really exceptional quality tools with just breathtaking performance that will provide a lifetime (or even generations, if possible) of faithful, hard service than save a dollar or 5 on each one...



I guess what I'm getting at is when you find some tool you you like and decide not to get it because you find out it is made made of some inferior material, you say to yourself, ``I might have bought that if only it had made of ...'' what?



Comments to the tune of ``just go buy the stuff'' will be redirected to /dev/null. I've got my reasons...


snipped-for-privacy@ElectEngrngCompSci.CaseWesResUniv.EDU

If carbide is the work edge, then mild steel for the body that's holding it.

Cast iron? Spark test it to confirm.

That's up to the user, not the steel.

Frank Morrison

Get some 4340 Chrome moly condition M. It is really stong and will do enverything your talking about plus it heat treats nicely if your so inclined.

Charlie

We often used 4140 "prehard" for such an application in the production shop I worked in a few years ago. Hardness comes in at 32-36 Rc and the machinability was decent.

Chris

Thanks for the advice. I'll give it a try. I kinda figgered I would not be the first person on the planet to have such requirements. :-)

You have a preferred vendor of same, before I just pick someone at random?

Thanks, tg.

Charlie wrote:

How about good old 0-1? Cuts like butter and can heat-treat to any hardness, cheap and won't warp enough to wory about. A little hot wax treatment and it wont rust for years.

"The original Tom Gardner"

Plus, as an added benefit, the wax job will help it to lose all that unwanted, unsightly tool hair! Nobody likes fur on their tools. Makes for a lousy finish on the parts you make with them...

tg.

Fry Metals in LA may be able to help you. The 4130 preheatreated works good too as the other gentleman stated but it isn't as strong. The

4340m will aproach 300k when heat treated. You said price wasn't a factor and if it wasn't a factor this is what I'd make my steel tools out of.

Charlie

Well, as far as $$$ goes, it's a sliding scale. If a particular material costs 10% more but is a little better than the next best thing, I'd go for it. If it costs 100% more and is vastly superior, I'd probably go for it in that case too, but if it costs 100% more and is only a shade better, I'd probably go cheaper. You know how it works. I guess it also depends on the overall price. If we're talking about the difference between $1/tool and $5/tool, that isn't worth worrying about on a $100 tool.

Also, machining will play a part too. If something is so beastly to machine that it ends up costing me an extra $100/part in time and tooling used to cut the stuff, that would definitely go on the negative side of the scale.

I'll have to do some experimentation. All these things will have to be weighed against one another. It's a bit of a long term project. A long term project that might not even pan out. It's in the ``let's just see'' stage right now.

Thanks to everyone for all the good suggestions. I'm looking into them.

Thanks, tg.

Charlie wrote:

Bwahahaha, Don't you have enough projects going? (Pay no attention to MY project book!)

No kiddin'. Never time to finish anything, but always thinkin' about a new project. Projects comin' out my ears. I've been meaning to go see a doctor about that...

I think shop work is a lot like what a friend of mine once said about his boat work: ``You never really finish your boat work. Sometimes you just stop.'' Although, he did usually manage to finish particular projects, so this isn't quite the same...

L8r, tg.

Tom Gardner wrote:

Here is a link to a "Tool Steel Selector"

formatting link
just hauled a drum of "A9" home to feed the furnace. Alan Black

Thanks a bunch Alan. I paid them a little visit already.

Thanks, tg.

Alan Black wrote:

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