Perhaps I've overlooking something obvious, but in perusing the MSC,
McMaster and Enco catalogs, I've noticed that there do not seem to be
any ready-made HSS cutting tools for lathe use. I seem to have a choice
between either premade bits of carbide brazed to a steel shank, a holder
and carbide insert system, or HSS blanks for grinding custom tools. I
expected to find ready-to-use HSS cutters of all shapes and profiles,
with a choice of shiny, TiN, TiCN etc.. just as with drill bits, but
these don't appear to exist and I'm curious why. Has carbide obsoleted
these things, or did they never exist at all?
I saw them in McMaster catalog. Look in later addition or on their webpage.
I was surprised when I saw them becuase I have never seen anyone sell
preground toolbits before (except sherline and I wasn't impressed with the
ones I received).
Some of the hobbyist suppliers such as Blue Ridge Machinery used to sell
them, but I don't know if they still do. I don't think they were ever sold
for industrial use. There is some outfit that advertises in HSM that sells
lathe tools designed for HSS inserts. They also sell the inserts<G>. IMHO
most serious hobbyists with 6" or better lathes have switched to carbide
(brazed or inserts) for normal work, reserving HSS for form ground specialty
The only time I have seen pre-ground HSS tools (other than those
which came in an old machinist's chest, where the previous owner had
ground them) was in sets for new owners of hobby lathes.
The set of tools in the machinist's chest were an interesting
education in what can be done with HSS.
The basic reason for the continued existence of HSS tool bits
(blanks) is that they offer the flexibility to grind to *any* needed
shape (e.g. form tools) -- and to *re*-grind at need once they get dull,
or when you need a different custom shape and no longer need the old
And -- they can be ground a lot sharper than most carbide,
especially sharper than tools with TiN coatings. Also, TiN coatings
would suffer at the first re-grind. For drill bits, it is not
(normally) a problem, because the grinding is on the end, and the
primary benefit offered by the TiN coating is a smoother slide up the
flutes for the chips. An exception is when you need to "dub" a bit to
use for things like brass, where a rake on the cutting edge can draw the
bit into the workpiece. But for brass -- you don't need the TiN coating
I usually use carbide insert tooling in special tool holders,
but I do grind HSS for special cases, and I keep a few unground 1/2"
cobalt steel tool bits for that purpose. (And I have two Stellite ones
for that special situation where the Cobalt steel is not enough.
The most recent home ground tools were a pair of Acme threading
tools for inside and outside threads that were just too big for the
insert tooling which fits my lathe to handle. The holders for the next
size up were too big (and too expensive) for my BXA sized quick-change
toolpost holders, so HSS was what made sense -- one in a standard tool
holder, and one in a boring bar.
Note that I had to calculate angles for the Acme bits to set
them up for a given pitch and diameter. The insert tooling for Acme has
a series of solid carbide anvils to go under the inserts to tip them at
an angle appropriate to the needs of a given thread to match the pitch
It is worth while learning to grind tool bits, even if you
mostly use carbide inserts.
If you really want HSS, and don't want to learn to grind it, I
have read of HSS inserts to fit the shanks for carbide tooling.
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Chronos in the UK http://www.chronos.ltd.uk/ sells sets in several sizes. I
would check Blue Ridge Machinery in the US as well. I know I've seen them
in a US catalog. If you're just getting started, having a set of pre-made
ones might be very handy as they will give you a great example of what your
tool should look like. The diagrams shown in most books on grinding lathe
tools I found very confusing when I was first starting.
My practice is to rough grind them free hand from blanks, and then use a jig
to finish grind them to the correct angles. It's not hard after you've
ground a few blanks. However, if I could have bought an already ground set
starting out, I would have.
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