Jack Schmidling wrote:
I need a piece of 1/4" hardened drill rod about 33" long but I have no great
ideas on how to heat treat such a long piece myself and can't seem to find a
source for pre-hardened rod.

Anybody know a source? It doesn't have to be ground or of any precision at
all, just a nominal 1/4".

It occurs to me that air-hardened material may be a possibility but I am not
clear on how this is done.

js


How hard does it have to be? Would 1/4" music wire do?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

why don't you go with a piece of Thomson shaft, it is already hard and comes
undersize by a couple of thousandths.

Reid Tool carries it so does MSC

It comes in 36" length

Reid part # TLM_1605 $42.48

msc part #56540495 $25.30


CT

"Tim Wescott" wrote in message
...
Jack Schmidling wrote:
I need a piece of 1/4" hardened drill rod about 33" long but I have no
great
ideas on how to heat treat such a long piece myself and can't seem to
find a
source for pre-hardened rod.

Anybody know a source? It doesn't have to be ground or of any precision
at
all, just a nominal 1/4".

It occurs to me that air-hardened material may be a possibility but I am
not
clear on how this is done.

js


How hard does it have to be? Would 1/4" music wire do?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

In article ,
says...
why don't you go with a piece of Thomson shaft, it is already hard and comes
undersize by a couple of thousandths.

Reid Tool carries it so does MSC

It comes in 36" length

Reid part # TLM_1605 $42.48

msc part #56540495 $25.30


Or $17.46 from McMaster. The size is closer to .0005/.001
under nominal, and it's very straight.

Exact cut lengths can be special ordered thru a bearing
distributor if you don't want to fuss with cutting through
the hard case, but it can be cut easily with carbide or
with abrasives.

Ned Simmons

Hardening involves heating the rod to a dull red, then quenching in oil
or water according to the steel. It will be hard, but brittle as glass.
The temper needs to be reheated [drawn] to whatever hardness you want
in the finished product. Spring temper is the last stage of drawing
before complete annealment.
The old blacksmith's oxidation colors a
Light straw yellow - Gravers, burins, wood chisels
dark yellow - Cold chisels, wood chisels [heavy]
ruby red - axes, picks, impact tools
purple - heavy impact tools
blue - springs
black - soft annealed
These colors are seen on a polished area of the hardened steel as it is
reheated.
Blacksmiths hardened the points of picks, bars and chisels by quenching
[hardening] the tip of the tool, quickly polishing the end, then
letting the heat run back into the tip until the desired color
appeared, then cold quenched it. This was to leave the body of the tool
softer to handle impact.
Modern tools that you can buy over the counter are tempered much softer
so the manufacturers liability is reduced. [the tool will bend, not
break]
I retemper most of my tools. Pocket knives are especially bad today.
Bugs

Jack Schmidling wrote:
I need a piece of 1/4" hardened drill rod about 33" long but I have no great
ideas on how to heat treat such a long piece myself and can't seem to find a
source for pre-hardened rod.

Anybody know a source? It doesn't have to be ground or of any precision at
all, just a nominal 1/4".

It occurs to me that air-hardened material may be a possibility but I am not
clear on how this is done.

js



Don't know where to find pre-hardened shaft but if you end up having to
do it yourself, it's gonna be tricky hardening the whole thing without
warping.
I'd get oil-hardening steel (O1) and rig up a "furnace" with a pile of
firebricks and a coiled nichrome element set in a channel formed by the
firebricks. You need a temp control to regulate the element, an
electric rangetop burner control will work.
Heat the shaft red hot until it loses it's magnetism, and hold it at
that temp for 15 minutes--that's called "soaking" and makes sure the
heating reaches the inner core of the metal.
Use olive oil for quenching, although cheaper vegetable oils will
probably work OK.
The best way to avoid warping is to quench the shaft vertically so a
tubular container for the oil could be made from PVC drainpipe with a
cap glued on the bottom.
Do the quench quickly, grab an end with visegrips and drop it straight
down into the oil then agitate it up/down and around for a few seconds.
Then to draw the temper as another poster outlines, use the firebrick
furnace again with the heat turned down low after polishing the shaft
bright to see the oxidation colors.

Ken Grunke

--
take da "ma" offa dot com fer eemayl


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