Turning spring steel (piano wire)

I need to make a few adaptors in 5mm spring steel (piano wire) and have run into
a problem, the parts are very simple being a 4mm section around 4cm long with
the rest of the 6cm overall length being left at the stock diameter.
The original plan was to use brazed tip tools to turn the parts but the very
first attempt to part off a length of the wire broke the tip off the parting
tool. The material did seem to be machining OK up to the point the tip broke
but I think the flexibility of the wire led to vibrations which got the better
of the tip. My only other turning tools are HSS and although they will
obviously be tougher I wondered if they will be hard enough to maching the wire
in its as supplied (springy) state ? I don't have heat treating facilities and
so don't want to attempt the anneal, machine, harden and temper cycle.
Any ideas ?
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Got a gas hob and a saucepan full of water?
regards Mark Rand RTFM
Reply to
Mark Rand
That's a long thin section to be turning. You have a follow rest, I presume.
If you *can* consistently turn that 40mm down, I'd part with a dremel cutoff blade - but even possibly simpler solder a 5mm tube 20mm long over 4mm wire - could such a tube be brass? If you cannot get it with the right OD you could still more easily turn that than the steel.
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I am fairly certain that the vibration is the cause of the problem, I would use a roller box by choice, so failing that a bush at bar size attached to the tool and close to it would restrain the material during turning, I would use carbide and lots of coolant, Peter
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Yerss, but...
... the wire is supplied in the right temper (springy) for use and I am pretty certain to cock it up when I either anneal it or re-boinggg it. I know a better person would try it for the experience but, well, I ain't :-)
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Well in the end I contacted the manufacturer of the parts (toy aeroplane oleo legs) I need the adaptors for and they agreed that boring out the 4mm hole to 5mm will have no ill effects on the part so I'm going to do that and avoid the problem. My reason for considering adaptors in the first place was a 5mm hole reduces the wall thickness but if they think it's OK then I will try it and see.
Thanks to you all for your suggestions,
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Good quality HSS, sharpened with a decided 'hook' positive edge IYSWIM. *REALLY* pointy, You should be able to shave a thin sliver off your fingernail with it. Id run a job like that on the unimat, in top speed (4000rpm iirc) and take very light cuts. Probably need a follow rest, but in a pinch (depending on how many you need) you can use a piece of hardwood pressed against the back of the rod. cut a little V in it first, and use a drop of oil. helps prevent chatter too :) Obviously only stick out the 4cm you need to turn down, and use a collet chuck so you can run the length required without a nasty chuck crossslide interface moment.
hth Dave
Reply to
dave sanderson

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