Keystock as Lathe Bits ?

I have a box of rust covered bits of square bar I got along with a small
lathe I bought a few years ago. There were some carbide tipped junk junk
bits in the box, but it mostly looked like keystock. I was poking thru the
box the other day looking for one of those pieces of carbide when I noticed
what looked like an actual HSS lathe bit (unground). It had the undercut on
each end that comes on a lot of lathe bits, so I walked it over to the belt
sander and knocked the rust off. A name appeared on the side of it. I
can't recognize the name, but a name appeared none the less. I went ahead
and ground one end to a nice conservative right hand tool and put it in the
HSS bits drawer for my big lathe. Worse comes to worse I'll smear the end
off, but it took some work to grind so I don't think so.
Anyway, after finding that piece I went thru the box again one peice at a
time looking to see if there were any more. Except for the carbide tipped
mystery metal there were no more obvious lathe bits. The rest all looked to
me like precut keystock to me. Slightly rounded edges and a squared off end
with slightly rounded edges. Out of curiosity I grabbed my spring punch and
hit several peices of it with the punch, and then I went and got that lathe
bit and hit it with the spring punch. They all got a very tiny divot or
punch mark, but the mark seemed to be the same size on all of it. So... is
is all this square stock just a different shape of blank HSS bit or is it
the keystock it looks like to me? If it is just keystock can it be ground
and used for lathe bits in a pinch or would it be not quite hard enough?
I am just curious. I've got a decent selection of insert tooling and a few
pieces of known good HSS ground for stuff I don't have inserts for.
Reply to
Bob La Londe
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I've got an old Unimat lathe with bits that look like they're made out of keystock, but act like they're made out of HSS.
Reply to
Tim Wescott
Some of the older high-performance tool steels like Tantung appear to be cast or forged. --jsw
Reply to
Jim Wilkins
Key stock is normally just mild steel. A file should tell you the difference.
Reply to
John B Slocomb
Keystock usually is just plain carbon steel -- not very hard. Try it and se e how it performs.
High speed steel is not only hard (typically 62 - 66 Rc), but it has a temp ering temperature of around 1,000 deg. F. Sometimes a little more (M4, M42 and above). You can use it right up to the tempering temperature without pe rmanently softening it. That's why it's called "high-speed." You can run th e cutting speed up until it just barely glows red -- in a fairly dark room, at least.
If you have some hard steel that's not HSS, you can do some cutting with it at low speeds. If it's plain carbon, it ought to take 450 deg. F. That's w hat was used before we had HSS. My old friend at American Machinist used mu sic wire for cutting tools on his Unimat. That's pretty hard, but it's plai n carbon steel.
Reply to
edhuntress2
Keystock usually is just plain carbon steel -- not very hard. Try it and see how it performs.
High speed steel is not only hard (typically 62 - 66 Rc), but it has a tempering temperature of around 1,000 deg. F. Sometimes a little more (M4, M42 and above). You can use it right up to the tempering temperature without permanently softening it. That's why it's called "high-speed." You can run the cutting speed up until it just barely glows red -- in a fairly dark room, at least.
If you have some hard steel that's not HSS, you can do some cutting with it at low speeds. If it's plain carbon, it ought to take 450 deg. F. That's what was used before we had HSS. My old friend at American Machinist used music wire for cutting tools on his Unimat. That's pretty hard, but it's plain carbon steel.
Reply to
Howard Beel
We often made boring bars for one off jobs from "drill rod". Takes very little time to forge and temper grind it to shape. Even keeping the cutting speed down to carbon steel speeds it was still a quick way to get a job done :-)
Reply to
John B Slocomb
I make custom tapered drill bits from O-1 rod, for instance a 20 degree taper for a convergent air nozzle. They cut well enough if slowly when milled half round into D bits. A thin coating of Ivory soap minimizes scaling loss when hardened. --jsw
Reply to
Jim Wilkins
Maybe try bending a piece. HSS doesn't bend very well (snap!) and most tool steels don't either (shrug).
Reply to
Leon Fisk
If you meant that in the onomatopoeic sense, and if it shrugs, it probably won't cut very well. d8-)
Happy Thanksgiving, Leon and all.
Reply to
edhuntress2
Geesh, good thing I have a dictionary, editors...
I actually have some very similar pieces around somewhere. Dad picked them up many years ago and we always wondered if they were some sort of blank tool steel. Next time I come across them I'll try the "bend test" on one :)
Happy Thanksgiving to you too and all the rest!
Reply to
Leon Fisk
May I politely suggest that you don't?
Lathe bits snap violently like overstressed steel cable, and the flying fragments are sharp as glass.
I'd try the spark or scratch tests, or see if it holds an edge cutting steel in the lathe.
--jsw, btdt
Reply to
Jim Wilkins
[ ... ]
Is it even *carbon* steel? I think that what I have is just plain mild steel -- not enough carbon to harden. (I've never tried, since I don't see any benefit to hardening a key.)
Also -- I don't think that I have ever seen HSS rust. I guess that it is possible, but uncommon.
Compare the previously mentioned (and likely now snipped) automatic center punch test -- before and after a heat and quench cycle to see whether it does harden at all.
Sure -- drill rod is a relatively high carbon steel -- made to be hardened. Three common flavors -- water hardening "O1" (quench in brine, not plain water, I believe), Oil hardening "O1" (quench in oil), and air hardening "A2" and "D2" (just let it sit in air until it cools.)
For most purposes, they all need to be tempered so they are not *too* brittle beofre use.
Enjoy, DoN.
Reply to
DoN. Nichols
Learning new things keeps you young. d8-)
I have an inherited box of 1/4" and 3/8" keystock. It looks a lot like my box of old HSS lathe-bit stock. I've never done anything with them, but I'll spark-test them when I get a chance.
It was a great one. 'Hope yours was as good.
Reply to
edhuntress2
Plain "mild steel" is carbon steel. A lot of jargon common terms confuse th ese things. Even the mildest steel contains carbon, at least 0.08 %. The se ries starts with 1008, which was once used for stamped car-body parts.
1008 won't harden noticeably. When you get up to 1020 (0.2% carbon), it wil l work-harden a bit but barely quench-harden. Quench-hardening starts at ar ound 1040, but even that doesn't harden much.
In theory, 1070 will get as hard from quench-hardening as any higher carbon steel. But in practice, it doesn't, supposedly because of the way carbon i s distributed in the iron. 1090 (0.9% carbon) comes close but music wire ru ns up to around 1.2% carbon. That will draw to very high hardness, but I'm told it doesn't quench-harden any more than 1090. 'Dunno, I've never tried it, and I no longer have access to a Mitutoyo hardness tester, anyway.
Keystock comes in a variety of materials but the common ones are 1018 and 1 045.
It is somewhat rust-resistant, but it will rust.
4564
Reply to
edhuntress2
O.K. Yes, pretty mild steel as they go. :-)
O.K.
I've recently gotten some music wire at about 0.060" diameter, and boy is that nasty to cut. Compound leverage wire cutters with carbide blades (Starrett) can do it -- but it is still sudden when the cut occurs. :-)
O.K. What I have is likely the 1018, based on the feel filing it.
O.K. Pretty much I guess I haven't exposed it to nasty environments. :-)
Thanks for the additional information.
Enjoy, DoN.
Reply to
DoN. Nichols
I use a thin cutoff wheel on a Dremel. It's the only way I've ever found to cut it clean, and it works great.
Music wire is plain carbon, with an extremely high percentage of carbon. Most brands use a proprietary stock material, but it's usually 1.0 - 1.2% carbon.
It isn't heat-treated. It's just work-hardened from drawing the wire. In the thinner pieces, the tensile strength can reach 300,000 psi and the hardness is comparably 'way up there.
Reply to
edhuntress2
Well ... this was a clean cut -- if you like chisel points. Maybe that for one end, and the cutoff wheel for the other end to make watchmaker's chisels. :-)
With other weird alloy components for their desired effects? Sort of like the flat spring stock used to make accordion reeds. (For that matter, English concertinas started out with "brass" reeds, which I think were an alloy really called "reed bronze", and no longer available as far as I know. (Probably, BeCu would be excellent for the task, except for the hazard to those tuning the reeds, which is done either by filing or by grinding -- neither of which is desirable to breathe around. :-)
Hmm ... how close to what is needed for the "space elevator" project? IIRC, even carbon fiber is not yet strong enough.
For that matter -- do we have anything yet which is strong enough for the same project on Mars (once we get there?) With the lower gravity, that should be easier. And even easier for the moon, assuming that the Earth's gravity would not perturb the stability of something like that on the moon.
Enjoy, DoN.
Reply to
DoN. Nichols
Not really. As I mentioned, the material stock is usually proprietary. Ther e is an ASTM standard for "music wire" (ASTM A228), but it's really just a designation for a type of spring wire, which probably is what 90% of "music wire" is used for. It's 1.0 % carbon and it contains around 0.30 - 0.60 ma nganese and a bit of sulfur, the latter probably to make it draw better.
Basically, it's really clean, high-quality extreme high-carbon steel, and, despite the miniscule amount of manganese, it's considered to be a plain-ca rbon steel.
I don't know.
Sorry, I don't do astrophysics. Just earthbound materials science. d8-)
Reply to
edhuntress2
Not really. As I mentioned, the material stock is usually proprietary. There is an ASTM standard for "music wire" (ASTM A228), but it's really just a designation for a type of spring wire, which probably is what 90% of "music wire" is used for. It's 1.0 % carbon and it contains around 0.30 - 0.60 manganese and a bit of sulfur, the latter probably to make it draw better.
Basically, it's really clean, high-quality extreme high-carbon steel, and, despite the miniscule amount of manganese, it's considered to be a plain-carbon steel.
I don't know.
Sorry, I don't do astrophysics. Just earthbound materials science. d8-)
Reply to
Jim Wilkins

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