so I have a tooling project that involves a bit of reworked HSS
jointer knife. I want to make a wood bodied spokeshave in the old
style, with the blade mounted through the body on friction fit tangs.
so I ground out the blank from the jointer knife with the tangs
attached. the next step is to either bend the tangs 90 degrees or cut
them off and braze them back on at 90 degrees.
now, I strongly suspect that this is an HSS blade, dull sparks and all
that, but I'm not able to say for sure that that is what it is.
I have read about HSS that it doesn't behave well being heated after
it's own rather high tech hardening and tempering process. I'll be
using an oxy-acetylene micro torch to do the bending- the cross
section at the bend is roughly 1/8" square. I can get the area I want
to bend up to a nice bright red without getting the cutting part of
the blade hot enough to mess with the HSS, and if I cool it slowly I
may be able to avoid shocking it. I don't mind leaving the tangs
annealed, but I'm worried that there will be zones around the heated
area that will include some of HSS's more brittle states and that the
tangs will just snap right off.
any advise?
Yeah. Try it and see. <g>
First, jointer blades are traditionally D2, not HSS. Most of your problem is
the same either way, however.
This is pure guess, based on playing a bit with these steels but not doing
quite what you have in mind: I think you'll be able to get away with it. If
you work quickly, you should be able to wrap a wet rag around the part you
don't want to wreck and keep the temper. Watch out for the steam.
The "mess"of re-heat-treating HSS is mostly a matter of trying to restore
its high-temperature hardness. But you don't have to do that. If you did
have to re-treat it, you might get away with a simple heat-and-quench and
not worry about the solution hardening part. The transition temperature is a
bit higher than for carbon steel but, if you aren't restoring the high-temp
capability, you don't have to sweat getting it hot enough to put the
carbides back into solution.
I think. I don't really know if leaving them in their precipitated state
would hamper bending the tangs with heat, but I don't think so.
You may get lucky and find someone here who really knows the answer but it's
a pretty unusual thing you're doing. And, again, it's more likely D2 than
HSS. That doesn't present as much of a carbide issue.
Do you have a scrap of the blade left to give it a test? If so, that's your
best bet.
--
Ed Huntress
Ed, I've never seen a HCS jointer knife before. Perhaps they were
common "way back when" but everything's HSS or carbide (insert or
brazed) these days.
Regards,
Robin
Well, I just took a look online and it looks like most of the standard
jointer knives are still D2, with HSS as an extra-cost option. The last
factory set I bought for my Delta 6" jointer was D2.
--
Ed Huntress
Not that I know of. I've never tried to distinguish them with a spark
test -- they both make fat sparks like a lot of high-alloy tool steels --
but I was never looking for the difference, either. Maybe someone here, or
on alt.machines.cnc, can tell you how to spark-test them.
My first thought was that it should, theoretically, be easier to forge, and
a quick look online shows that both D2 and HSS are forged in commercial
operations. But knife makers and other small-scale operators seem to be
saying that both are difficult to forge without shattering them.
Since both D2 and HSS are used in custom knife-making, you may want to look
for a nest of knife makers and ask there. Someone here should be able to
steer you to them, if you're patient enough to wait for one to show up.
I assume you're making an old-style drawknife, right? I have a big one
that's been in my family since the late 1800s -- the blade is getting pretty
narrow, and I think it's been used to de-hair a few horsehides <g> -- and it
has the fine, right-angle tangs you're describing. I also have a short one I
made years ago out of an old HSS power hacksaw blade, which I've used a few
times for working green wood. I didn't try to make tangs. I just pinned it
at both ends to a piece of drill rod with two rivets on each (holes drilled
with a carbide-tipped bit in a drill press), and I set the drill rod into
maple handles by scorching them into undersize holes in the maple. That's a
traditional way to fix handles onto a lot of tools, from gouges and chisels
to screwdrivers. Epoxy is good for holding the wooden handles on, too, if
you aren't sure about the scorching method. Pinning or silver-brazing some
rods onto the blade would save you a lot of trouble if you aren't intent on
copying the aesthetics. I just ground flats along an inch and a half or so
of the drill rods and fastened them to one side of the blade. It works fine.
BTW, I wore out a pretty good aluminum oxide wheel grinding the teeth off of
the hacksaw blade, and it made a heck of a mess of grinding dust all over
the shop. I suspect that a silicon carbide wheel would have stood up better.
--
Ed Huntress
On Sun, 30 Nov 2008 22:58:23 -0800 (PST), the infamous
snipped-for-privacy@yahoo.com scrawled the following:
I bought a Ron Hock iron from Spokeshave way back when. He inserted
studs for knurled nuts to adjust the height. I really prefer that to
the ol' "beat on the tang" adjustment system. ;) The irons are made
from a high carbon steel. Hock also uses A2 for plane blade styles.
http://www.hocktools.com/teachshave/teachshave.htm (Hi, Spokie!)
G'luck in your endeavor.
--
The only difference between a rut and a grave...is in their dimensions.
-- Ellen Glasglow
Right on the D2, (I don't think it can be bent successfully at any heat
without a draw first). But I could be wrong (I think it is available in
drawn welding wire).
My notions about HSS is that you have "one chance with it after the
melt". Pretty sure forging is done at a lower temp than the Ac3 temp
where HSS does its voodoo.
Matt
On Nov 30, 4:13 pm, snipped-for-privacy@yahoo.com wrote:
I have had no luck bending hardened HSS. I wanted to put a slight
hook on the end of 1/8", 3/16", and 1/4" square tool bits. I bought
the tool bits from ENCO, so the quality was questionable. I heated
with an Oxy/Acet torch. In all cases, I could melt the edges or the
bulk, however when I went to bend the material, it was very firm, and
fractured along large boundaries. (looked like a hard cheese). YMMV.
Dave J.
As others will mention, HSS can be brazed and/or silver soldered to any
other braze-compatible material without sacrificing the ability for the HSS
to be sharpened, and hold a sharpened edge (essentially no loss of
hardness).
I'm fairly certain of this, as I've mounted HSS to steel with a MAPP torch,
then sharpened the HSS for use in turning steel workpieces in a lathe, and
as a flycutter for milling steel.
As someone mentioned, you won't be able to bend HSS, not even with torch
heat.
If a small feature (handle tang/stem, for example) is created by grinding
away a portion of the HSS piece, I would expect a small feature to be too
fragile for use as a woodworking tool.
HSS doesn't anneal like common high carbon steels do.
Small cross-sections of HSS are fairly weak, and very likely to break when
side pressure is applied (snap like a drill that's flexed sideways).
I'm not sure that I've seen the type of spoke shave you're referring to,
except possibly a quick view of one on The Woodright's Shop on PBS.
I have seen a lot of draw planes, and they seem to be about as common as
dirt (here in the northeast US), it seems many of 'em are just bought for
wall hangers, to display rather than to actually use.
Only up to around 1,000 or 1,100 deg. F, Iggy. That's the limit. The
precipitation hardening starts to break down beyond that temperature. That's
a very dull red, hard to see in bright light.
Someone mentioned that HSS requires a special anneal, which is true, but HSS
is forged to make various cutting tools, commercially, so there must be some
way to do it.
--
Ed Huntress
Metal lathes use high speed steel from simple to exotic.
It comes pre-hardened. One cold grinds the cutters and hand laps on
India stone and the like.
It resists movement.
Martin
Ed Huntress wrote:
On Sun, 30 Nov 2008 23:39:39 -0600, Ignoramus13690
There are plenty of materials that are difficult to bend at high
temperatures but make lousy cutting tools. High speed steel's main
virtue is that holds an edge at high temperatures. The two are
related, but not the same thing.
This aspect of HSS is often misunderstood and misrepresented by the
uninitiated.
So many folks still regard getting HSS hot as being detrimental to the
cutting tool, when it's not.
The other point which is an old bad habit repeated thru the
years/generations is that dipping hot cutting tools into water to cool them
off is beneficial.
Well, it is beneficial for not turning fingertips into leather, but
otherwise not good for the cutting tool (not so bad at moderately warm/low
heat, but definitely not good at high heat, color changing ranges).
I usually gather up several cutting tools, and/or some new blanks for
shaping, and set each one aside on a steel plate to cool, then pick up a
cool one to handle and grind next.
This works out really well, for me anyway.
I don't suffer burned fingertips anymore, since making these tool holders
for grinding square HSS lathe cutting tools:
http://www.kwagmire.com/tools/broach_tool.html
With a hex wrench and a parallel-jaw plier, I can swap out HSS cutting tools
quickly for grinding small batches in one session.
Using two of these holders makes a session go fairly quickly for 2 different
sized cutting tools.
so really my question is about spot annealing HSS and what that does
to the immediately adjacent metal. can I get HSS hot enough to bend
with my OA torch, and what will I have when it cools?
In case you missed the earlier replies, heating the piece (or parts of it)
will not anneal it to a softer more manageable state if the piece is
actually HSS. The factory methods of annealing HSS are too complex to
duplicate.
The piece may anneal if it is another type of tool steel, but bending with a
torch may still not lead to good results.
One reply suggested that you reconsider your method of mating/attaching the
blade to the wood part.
Another suggested that you locate some high carbon steel to use as a blade,
and that it is the traditional blade material.
Another suggested that you braze or silver solder some features onto your
existing piece, to make mounting/securing the blade to the wood section.
see below..
Yeah. Try it and see. <g>
First, jointer blades are traditionally D2, not HSS. Most of your problem is
the same either way, however.
This is pure guess, based on playing a bit with these steels but not doing
quite what you have in mind: I think you'll be able to get away with it. If
you work quickly, you should be able to wrap a wet rag around the part you
don't want to wreck and keep the temper. Watch out for the steam.
The "mess"of re-heat-treating HSS is mostly a matter of trying to restore
its high-temperature hardness. But you don't have to do that. If you did
have to re-treat it, you might get away with a simple heat-and-quench and
not worry about the solution hardening part. The transition temperature is a
bit higher than for carbon steel but, if you aren't restoring the high-temp
capability, you don't have to sweat getting it hot enough to put the
carbides back into solution.
I think. I don't really know if leaving them in their precipitated state
would hamper bending the tangs with heat, but I don't think so.
You may get lucky and find someone here who really knows the answer but it's
a pretty unusual thing you're doing. And, again, it's more likely D2 than
HSS. That doesn't present as much of a carbide issue.
Do you have a scrap of the blade left to give it a test? If so, that's your
best bet.
--
Ed Huntress
=================
Not that I know of. I've never tried to distinguish them with a spark
test -- they both make fat sparks like a lot of high-alloy tool steels --
but I was never looking for the difference, either. Maybe someone here, or
on alt.machines.cnc, can tell you how to spark-test them.
My first thought was that it should, theoretically, be easier to forge, and
a quick look online shows that both D2 and HSS are forged in commercial
operations. But knife makers and other small-scale operators seem to be
saying that both are difficult to forge without shattering them.
Since both D2 and HSS are used in custom knife-making, you may want to look
for a nest of knife makers and ask there. Someone here should be able to
steer you to them, if you're patient enough to wait for one to show up.
I assume you're making an old-style drawknife, right? I have a big one
that's been in my family since the late 1800s -- the blade is getting pretty
narrow, and I think it's been used to de-hair a few horsehides <g> -- and it
has the fine, right-angle tangs you're describing. I also have a short one I
made years ago out of an old HSS power hacksaw blade, which I've used a few
times for working green wood. I didn't try to make tangs. I just pinned it
at both ends to a piece of drill rod with two rivets on each (holes drilled
with a carbide-tipped bit in a drill press), and I set the drill rod into
maple handles by scorching them into undersize holes in the maple. That's a
traditional way to fix handles onto a lot of tools, from gouges and chisels
to screwdrivers. Epoxy is good for holding the wooden handles on, too, if
you aren't sure about the scorching method. Pinning or silver-brazing some
rods onto the blade would save you a lot of trouble if you aren't intent on
copying the aesthetics. I just ground flats along an inch and a half or so
of the drill rods and fastened them to one side of the blade. It works fine.
BTW, I wore out a pretty good aluminum oxide wheel grinding the teeth off of
the hacksaw blade, and it made a heck of a mess of grinding dust all over
the shop. I suspect that a silicon carbide wheel would have stood up better.
--
Ed Huntress
====================
I bought a Ron Hock iron from Spokeshave way back when. He inserted
studs for knurled nuts to adjust the height. I really prefer that to
the ol' "beat on the tang" adjustment system. ;) The irons are made
from a high carbon steel. Hock also uses A2 for plane blade styles.
http://www.hocktools.com/teachshave/teachshave.htm (Hi, Spokie!)
G'luck in your endeavor.
=====================
Right on the D2, (I don't think it can be bent successfully at any heat
without a draw first). But I could be wrong (I think it is available in
drawn welding wire).
My notions about HSS is that you have "one chance with it after the
melt". Pretty sure forging is done at a lower temp than the Ac3 temp
where HSS does its voodoo.
Matt
====================
I have had no luck bending hardened HSS. I wanted to put a slight
hook on the end of 1/8", 3/16", and 1/4" square tool bits. I bought
the tool bits from ENCO, so the quality was questionable. I heated
with an Oxy/Acet torch. In all cases, I could melt the edges or the
bulk, however when I went to bend the material, it was very firm, and
fractured along large boundaries. (looked like a hard cheese). YMMV.
Dave J.
==================
Good input. I have had very good results silverbrazing HSS, both to
HSS and to mild steel.
=================
As others will mention, HSS can be brazed and/or silver soldered to any
other braze-compatible material without sacrificing the ability for the HSS
to be sharpened, and hold a sharpened edge (essentially no loss of
hardness).
I'm fairly certain of this, as I've mounted HSS to steel with a MAPP torch,
then sharpened the HSS for use in turning steel workpieces in a lathe, and
as a flycutter for milling steel.
As someone mentioned, you won't be able to bend HSS, not even with torch
heat.
If a small feature (handle tang/stem, for example) is created by grinding
away a portion of the HSS piece, I would expect a small feature to be too
fragile for use as a woodworking tool.
HSS doesn't anneal like common high carbon steels do.
Small cross-sections of HSS are fairly weak, and very likely to break when
side pressure is applied (snap like a drill that's flexed sideways).
I'm not sure that I've seen the type of spoke shave you're referring to,
except possibly a quick view of one on The Woodright's Shop on PBS.
I have seen a lot of draw planes, and they seem to be about as common as
dirt (here in the northeast US), it seems many of 'em are just bought for
wall hangers, to display rather than to actually use.
The magic of this type of tool isn't its hot or cold hardness but its
toughness. Good cutlery, wood saws, etc. benefit from being easy to
sharpen and hone.
Matt
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