From: od_willys (od_willys@netzero.net)
Date: Sun Oct 17 2004 - 19:32:45 PDT
For best results use drill bits that are coated with TiALN. These are used
for drilling any hardened metel as well as titanium and stainless steels.
They are available from any machine tool supplier. Travers in online at
www.travers.com They will do mail order.
Scott
'44 CCKW
'43 GPW
MVPA
----- Original Message -----
From: "jonathon" <jemery@execpc.com>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Sunday, October 17, 2004 7:44 PM
Subject: Re: [MV] drilling armor plate
> >The secret to drilling armour is to use a slow cutting speed. Reduce
> >the drill RPM down to a few hundred (at most) a minute and the
> >armour will drill just like mild steel.
>
> Not knowing the alloy content of the steel your talking about but I might
> suggest that the other secret which applies to many of "these kinds of
> alloys" is to feed hard. Slow drill speed but high feed rate, and of
course,
> as you stated, lots of oil or coolant. Even with a slow speed you may
still
> end up wearing out the drill from work hardening of the plate unless your
> feed rate is high enough to get under that layer. This also applies to
> stainless steel in most cases also. As to drills, just get a good
american
> or european made drill, M2 (HSS) or M42 (cobalt) Do not buy Chinese drills
> ever and do not waste your money on a carbide drill if your using a hand
> drill and if fact I'd say don't bother with carbide at all unless you have
a
> very controlled machining environment. Just my $0.01.
>
>
> later,
>
> je
>
>
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