[ham] [Rhodes22-list] stainless steel drilling

[Roger Pihlaja]

Michael,

OK, all of the 300 series stainless steels possess a property called "work
hardening".  It's the chromium in these alloy steels that imparts this
property.  Titanium alloys also work harden quite severely.  Basically, what
work hardening means is that when you start to deform the surface, like say
at the cutting edge of a drill bit, some of the cutting energy to available
to the local crystal structure of the surrounding metal & it rearranges
slightly, eliminating small local defects, & causing the surface to become
very hard.  I presume those stainless steel Schaffer backing plates were all
nice & shiny & polished, right?  Well, the polishing operation left the
entire surface work hardened!

So, here's what you need to do:  A titanium nitride (TiN - looks gold
colored) coated drill bit will work.  However, you must run the drill press
at a slow speed, say 30-50 rpm, use a gentle feed pressure, & apply a steady
stream of machining oil.  The oil stream, not only lubricates; but, also
serves to cool the drill bit & work piece.  If you let things get so hot
that you smell burning; then, it already too late.  The drill bit is gone.

Good Luck, Michael!

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Michael Meltzer" <mjm at michaelmeltzer.com>
To: <kroposki at innova.net>; "The Rhodes 22 mail list"
<rhodes22-list at rhodes22.org>
Sent: Saturday, August 02, 2003 10:57 PM
Subject: Re: [ham] [Rhodes22-list] stainless steel drilling


> a brand new colbat bit, barly got 8 1/4 to 3/8 holes out of it doing
everything right, still had to use a druml tool  to clean and a
> quickly polish holes up, that is tought and hardend stuff.
>
> MJM
>
>
> ----- Original Message -----
> From: "Kroposki" <kroposki at innova.net>
> To: "'The Rhodes 22 mail list'" <rhodes22-list at rhodes22.org>
> Sent: Saturday, August 02, 2003 6:02 PM
> Subject: [ham] [Rhodes22-list] stainless steel drilling
>
>
> > Michael,
> > Been there, apparently there are very hard kinds of stainless.
> > I just don't try to drill stainless.  It does not work.
> >                              Ed K
> >
> > -----Original Message-----
> > From: rhodes22-list-bounces at rhodes22.org
> > [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Michael Meltzer
> > Sent: Saturday, August 02, 2003 4:53 PM
> > To: rhodes22-list at rhodes22.org
> > Subject: [Rhodes22-list] it all your fault ed :-)
> >
> > ok, I pulled the backing plate for my hardpoints, went to west and got
> > barrel nut and the right size screews wanted everthing to look nice for
> > a piture, now my problem, I am not sure what those schaffer backing
> > plates are made of but I just watched them take out a bouch titiaun high
> > speed drill bit, 700 rpm drill press using cutting oil. That is f-cking
> > hard stuff and not the 316 i know. Any idea's what to drill them with?
> >
> > MJM
> > __________________________________________________
> > Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >
> > __________________________________________________
> > Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >
>
> __________________________________________________
> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>
>