[TheForge] A different needle question

[Steve Bloom]

At 06:24 PM 10/21/2013, Bruce wrote:
>​I am altering the eye shape of a few 
>commercial needles.  They're too brittle to work 
>without normalizing, but onc​ ​e normalized, 
>they bend just fine. Now I need them hard 
>again.  Well, dunking in water while at a red 
>heat works for that -- but leaves them more 
>brittle than ever. A tempering operation (to 
>purple or blue, probably) is quite easy on a 
>chisel, but even SEEING the colors on a needle 
>is a challenge.  For one thing, there's no good 
>surface to polish. I've tried a couple methods, 
>all without success -- my toaster over doesn't 
>get hot enough, like, maybe 450 F, despite what the dial says

Old trick for spring temper -- molten lead -- 
621F.  When there is still a dab unmelted, it's 
ready for the plunge.  This (I have been told) is 
the traditional way to temper flintlock springs 
and it has done it for me with slip joint folder springs.

steve