[TheForge] A different needle question

[Jerry Frost]

Thanks Bruce, that sounds good.

Though I am left wondering about the entertainment value of a mushroom
cloud; in the right neighborhood of course.

Frosty
-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce .
Sent: Tuesday, October 22, 2013 2:56 PM
To: mspencer at tallships.ca; Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] A different needle question

Okay, here's an update.  It happens there's only two degrees of separation
between me and Tom Latane', so here's an interpretation of a vague memory
(Marshall's) of Tom's approach to tempering a spring (influenced heavily by
information on hardening and tempering needles from an article in an early
edition of the London Encyclopedia (late 19th century, I think -- from
Google Books):

Heat to red and do all the bending work needed at this temperature.
Heat to red.  Allow to cool in air (to normalize).
Heat to red and immediately quench in veg. oil (to harden).
Heat oily needle over flame till oil bursts into flame and immediately
quench in veg. oil.

Seems to work.  Too soon to be 100% certain, but I've got about a half-dozen
needles reshaped, hardened and tempered by this procedure.  They seem hard,
and I haven't had anything break on me yet.

Bruce
NJ