Funny! I wondered where that tap went!

Thanks for the insight.

"john" wrote in message
...


Rob wrote:

"Damian Huckle" wrote in message
news
Hi guys,

I've just set up a Victor 16 x 40 lathe and did some practice turning on
a
2" hot-rolled mild steel round. No matter what variables I played with I
never got a satisfactory surface finish. The tooling seemed to pick-up
or
drag metal, and this would lead to small gouges in the finish. I tried
various things, but never could eliminate it consistently.

Any thoughts?

Thanks,

Damian




As Roy said it can be hard to get a good finish on hot rolled steel. I've
found the same as you - try finding some "free-machining" steel it turns
well with a nice finish. I don't know exactly what "free-machining"
means,
perhaps some one else will enlighten us. I guess the alloy composition
gives
it nice machining properties.

rob


Free machining steel has, pardon the word, "Lead" in it. 12L14, leaded
steel, cuts real easy with that addition of lead. Sulfur in the matal
will make the metal cut easier too. The smaller the tool nose radius the
easier it is to get a good finish. HSS bits will give you a decent finish
at lower speeds. Carbide needs to run at a surface speed of about 600 feet
per minute to get a good finish. On a finish cut you should be taking at
least .010 or it will tear the metal. Also you may have crappy metal
with a lot of "junk" in it. Some day you may be lucky enough to cut
through an unmelted tap or piece of stainless wire rope.

John