[sdiy] Machining aluminum, part deux

[Tim Ressel]

Also one must remember: twist drills have a "dead
center", which is a spot at the tip of the drill WHICH
DOES NOT CUT!! It just rubs and makes heat. This is
why you make a pilot hole with a 1/8" bit: it has a
really smalll dead center.

--TR


--- Dave Magnuson <resfreq at hoohahrecords.com> wrote:
> At 10:23 AM 4/18/02 -0600, Kenneth Martinez wrote:
> >Just drilled my first aluminum panel - worked fine
> with my bargain-store
> >drill bit set, once I got a small drill press (only
> $40).  No more
> >hand-drilling for me; and no need to make a small
> hole first & enlarge,
> >etc
> 
> 
> I think this might prematurely wear your bits.  I
> realize that aluminum is
> fairly soft, but heat is the number one killer of
> drill bits.  I'd still
> use perhaps an 1/8" or 3/16" pilot hole before going
> to the full sized
> hole... it just has the bit doing a little less
> work, and stays cooler.
> 
> Obviously, drill RPM and feeding speed are also
> factors in heat build up.
> Likewise, don't drill 40 holes in rapid
> succession... let your bits cool
> off ocassionally.
> 
> Personally, I center punch, drill a 1/8" pilot hole,
> and then use a
> step-drill or "Uni-bit" to enlarge to full size. 
> Gentle pressure on the
> drill, and allowing it to cool every 5 or 6 holes. 
> I've had the same $30
> Uni-bit for 3 years and it still cuts like new (I
> also use it on 16ga steel
> and light gauge stainless).  An added benefit: after
> the hole is the
> correct size, you can use the next sized step to
> chamfer the edge of the
> hole...  Saves a lot of time.
> 
> Dave Magnuson
> 
> Resonant Frequency:
> resfreq at hoohahrecords.com
> http://www.hoohahrecords.com/resfreq/index.html


__________________________________________________
Do You Yahoo!?
Yahoo! Tax Center - online filing with TurboTax
http://taxes.yahoo.com/