softening the end of ball screws

> Message: 24
> Date: Thu, 1 Jul 1999 14:20:48 -0600
> From: John Ross <johnr@...>
> Subject: Ball Screw Machining
>
> Hi I'm new (as of today) to this list, and I have a question about
> machining hardened ball screws. I have been converting my Mill Drill to
> ball screws as the article in HSM. Dan Falck has been giving me some advice
> on how he did this conversion. As Dan had did on his conversion I heated
> the ball screw in a lathe at its slowest speed (60 RPM), to a Straw color
> then let it cool before machining them. They are still extremely hard.
> I've tried reheating them but have had no better luck. Drilling the #7
> hole for a 1/4 20 center screw was darn near impossible and my tap won't
> even start to cut a thread. The ball screws I'm trying to use are from
> McMaster Car and they list them as "induction hardened to Rockwell 56-60C".
> Does anybody have any ideas as to how to soften these up so I can machine
> these beasts. My fathers suggestion to grind them is a little pricey
> considering I don't own a tool post grinder.
>
> John Ross

John, You are making it harder not softer! You must heat the end to a
dull red and then stick it in sand. Leave it there until it is cold. (A
long time) Look up Warner Electric's motion control page and there is a
FAQ about all of this stuff. I am not sure but they might be the ones
that McMaster is selling.
I have to do this trick myself on Friday. Trying to improve my Z axis on
my router.
Good Luck,
Don Chandler