How corrosion resistant is CPM M4 tool steel?

The subject is my question, I want to make a survival axe head of M4 or CPM M4 tool steel. I have heard great things about it's hardness, wear resistance and toughness but very little about ability to resist rusting. Any help would be appreciated and thank you in advance!

Reply to
good2get2know
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Personal experience with M2 is all I have on this subject.

I find that HSS tends not to tarnish. :/ So it doesn't tend to look cool like low-alloy high-carbon steel. If allowed to, it'll go directly to red rust spots and pits tho.

HSS knives made for and used in meat cutting don't tarnish or rust at all.

In the case of a hatchet smear it down with Vaseline? ;) In the case of a knife smear it down with Lard. ;)

What do you think? :)

Alvin in AZ

Reply to
alvinj

That isn't a bad idea just not suited for what my axe will be doing. I need something that can handle hard usage. Chopping branches, splitting wood and the like, something that will take an edge and will hold it even under extreme conditions. That is why I am evaluating HSS and other tool steels, they outperform every other steel except in corrosion resistance. That of course is why I posted here, cannot find any info about M4's corrosion properties. I worked at a groccery store in the meat dept when I was younger and we had to sharpen the blades constantly, and meat is a lot softer than wood, still a thought though. Thanks for the help and if you run into anything let me know!

Reply to
good2get2know

Certain high speed steels are stronger than most?/all? stainless steels and those like M2 and M4 can sure enough handle axe duty.

The main problem I have with knowing how they -all- compare is the lack of information and interest by industry in stainless steel's real properties. There's better stuff to be had in any and every direction other than corrosion resistance, so why bother with the cost of printing it out just for this dumb hick? :/ Stainlesss steel don't even make it to the -bottom- of the lists in other catagories BTW. :/

Thinking double bit axe or a single bit axe (that never gets driven with a sledge hammer like a wedge;). But even an HSS wedge would work (if heat treated right) could handle wedge duty too but put a big handle-hole in it and that's another problem. ;) But really tho, even the good-old ones couldn't handle much of that abuse either.

The main problems I see with an HSS axe is steel aquistion and then heat treating. Not strength. :)

Easier and cheaper (ebay for odd sized left over hunks plus the costs of heat treating) and prob'ly just as good of an axe too, would be S7, H11, H13 or A2 etc.

Are you the guy that was on rec.knives asking about HSS and later made some meat cutting knives from HSS ...like a year or two ago?

Alvin in AZ ps- T1, T2, M1, M2, M3, M3(high carbon), M4, M7, M8, M10 are all rated at the same high strength and the same high working hardness of 63-66hrc. :) A P/M version of any of those would be a step better in every direction except the new material price. ;)

Reply to
alvinj

My father worked for a dollar day as a lumber jack for a tiny saw mill back in the early 50's. He used a double bited ax that he only sharpened on one side leaving the other for rough cutting when the blade might get nicked up. If my memory is right his answer to a dull ax was a bastard file. Several years of hard use and sharpening didn't wear the ax out. I'm sorry but cutting tools get dull.

Reply to
deowll

Sorry no, never made any meat cutting knives or posted about such. Also the axe will not be used as a wedge. I am designing it as a survival axe with durability and ruggedness as it's chief strengths. Probable dimensions are 2 1/2'' square and 3/8'' thick with a slight angle on the edge where the top comes to a gradual point. The handle will be welded to the head so there will be no handle "hole" like with a wooden handled axe. The handle will have threads on the end for an extra extension to make it longer and allow greater force. I am taking blades that were previously used for tree trimming (9'' L x 4'' W x 3/8'' thick) and cutting it to relative dimensions with an integral handle as a prototype. The blades are not M4 (I really have no idea what they are but they are very tough). I spent the better part of today chopping hardwoods and after six hours I was still able to shave with it. The blades have no markings on them so I am unable to determine the alloy which is frustrating. Not only do they hold and edge extremely well but I forgot one of 12 outside the other day, after two days of exposure to rain and sun there is no sign of rust. Coincidentally if anyone can help me identify what these may be made of I would be very appreciative.

Reply to
good2get2know

"Certain high speed steels are stronger than most?/all? " From your generalities, I will assume that you are using a very broad definition that would include corrosion resistant steels. HP 9-4-.30 should get you to about

260ksi or more with better toughness than the tool steels. Too brittle for me though. I like Aermet 100 which will get you to at least 300ksi, comparable to M4 but at 5-6 times the toughness. It is not a true sta> > That isn't a bad idea just not suited for what my axe will be doing. I
Reply to
bainite

My Grandfather was in the CCC with a similar axe. I am here to tell you that technology including metallurgy has advanced a lot since then. It is a question of money not capability. Ask what a competition lumberjack pays for his axe and how he sharpens it.

Reply to
bainite

I sez, forget the high speed steel for this project. :/ Make the sucker from one solid hunk of S7 or H11/H13! :) (that's what they make jack-hammer bits from:) If "edge holding" was added to that list then-> A2. :)

Save the uses for M2/M4 for skinning and meat cutting chores? :)

Sounds like it could be D2 or something like it?

Spark testing is free, other than the short learning curve time, and maybe a few known samples to compare to.

After that you could tell us what the heck it is. ;) No kidding on that.

Alvin in AZ

Reply to
alvinj

Dunno, Alvin... Tradition blacksmith technique for axe making is to make the edge from your good steel and the eye from something tough, low carbon steel or even just iron.

I've seen it done and they start with a strip of hard steel maybe 6-8" long, 1-1-1/2" wide and 1/2" thick for the edge an a strap maybe 6-7" wide, 1/2" thick and maybe 12" long. first they forge the strap into a kind of pinched U shape (pardon my ugly ASCII graphics) and then forge weld the edge strip into the mouth of it. BTW - They usually forge the arc for the edge into the hard steel before that.

_________ / \ / ------- ( ###### \ ------- \_________/

However we've usually got real blacksmiths around here, so I'm sure one of them can correct me on the details. There are actually several variations on this theme. It may even be where the Japanese sword makers first got the idea for the hard edge, soft spine that they now do via differential heat treating. Chas should know more about that...

Reply to
Tom Xulliton

Agreed. :)

But I think he's making something that resembles a Buck(?) hatchet in design. Might as well make it out of one hunk of plate-steel like they do?

Either way :) what I'm picturing (don't know who made it but saw a picture of it once;) is basically a hachet-shaped cleaver. :)

Alvin in AZ

Reply to
alvinj

Didn't Estwing make solid steel hatchets? Head and handle all one piece.

Reply to
Del Cecchi

Yes but those are forged and look cool! :) The one I'm picturing (and I think this guy is too?) is one that still has the original flat surfaces and looks more like a re-designed modern cleaver.

"S7 from ebay" ;)

Alvin in AZ

Reply to
alvinj

Good ideas but (not trying to sound pissy) does anyone know about corrosion resistance of the M4.....?

Reply to
good2get2know

Not trying to not sound pissy...

HSS doesn't rust as easy as mild steel but no where near as rust resistant as D2.

Make it from D2 if corrosion resistance is important.

You could prob'ly get your hands on a saw-mill planer blade that's the right size and thickness, already heat treated and will hold an edge as good as anything you'll be able to tell a difference in.

I have a couple out in the scrap pile right now, BTW (and I live in the friggin desert;).

While on vacation in south central Arkansas we didn't have a hand grinder with a cut-off blade but we did have a torch and cut off a hunk of one (of a whole pile of these planer blades) for use as a well drilling bit. What a mess. But the home made drill bit got the job done and my ex-in-law's (she left me and the kids yippee;) neighbors got water after a couple days of relatively hard work.

My son took over the torch work and found out D2 don't cut so good with a friggin torch! :) What a waste of gas. :/

A quick run-out and measuring... 3/8"x 2+1/2"x 18" with one edge beveled a little more acute than 45 degrees. A pain to handle because of the weight plus that sharp-ass edge. ;)

I bet they make bigger ones than that. But more, a guy could prob'ly get a new one if he had cash. ;)

Alvin in AZ

Reply to
alvinj

"Del Cecchi" wrote

Good hatchets too. Aficionados said that the steel shank gave too much vibration, others didn't like the hard varnish on the stacked leather grip- good hatchet, had one for years and beat the shit out of it. I like their sample pick and rock hammer too.

Chas

Reply to
Chas

I bought a few of those and gave them away as presents but before I wrapped them up I hammered off the varnish and smeared them down with lard. :)

Alvin in AZ

Reply to
alvinj

wrote

No shit? Me too. That stinkin finish is harder than anything I ever saw but those yellow stocked chinese AKKlones. Make your hands blister in a heartbeat, doing any actual work with them. I use tree wax for the finish- kinda like Randall knives.

Chas

Reply to
Chas

Why am I guessing you didn't use them for geology. ; )

Fraser

Reply to
Fraser Johnston

So back to the topic question............

Reply to
good2get2know

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