From: Robert Bastow <teenut@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Update: Cutting Aluminum w/Abrasive Wheel
Date: Thu, 14 Oct 1999 13:01:55 GMT

Hi Matt.

Erm!

Seems to be a bit of confusion here still..

A "Cold Saw"  Is a HEAVILY built circular saw,running a large diameter High
Speed steel (Or carbide tipped blade on the more rigid machines.)

The blade runs at SLOW speed...Milling cutter speeds for the same cutter
material..a couple of hundred rev/min or less.

Can be of a "Chop" configuration on small machines. More usually a "roll in"
feed of the saw, to a fixed table on the larger machines.

Cold saws are used, primarily, for ferrous metals or for heavier sections of
aluminum, bronze etc

Always they are equipped with a heavy duty vise, flood coolant, accurate end
stops, and , on the larger ones, power feed, automatic stock advance and
sometimes, fully automatic cycling.

Definitely overkill and way too slow for your application.

This was not what Pete was recommending!

Abrasive cut off saw...High speed, much lighter build, "Chop" or Radial Arm
configuration. Often wrongly named and thus confused with a  genuine "Chop Saw"
as described below.

Usually fitted with a vise, sometimes with flood coolant auto stock feed etc,

Perfect for fast cuts on lighter sections of ferrous metals.  Nasty burrs, nasty
smells, smoke and other airborn contamination etc,  Wheels are a consummable and
can get expensive on heavy section cuts.

Probably the absolute worst choice for aluminum!!

Why..because aluminum conducts heat away too fast..Abrasive saws rely on local
heat to soften the material being cut.  Yet aluminum is also too maleable to be
"friably cut" (for want of a better term ;^) by the blunt trauma of the badly
shaped "cutting edges" in an abrasive wheel.  Add to that the  affinity that
aluminum has for aluminum oxide and its ability to tuck itself into every
available void "loading the wheel"..and maybe you can see why it is not the
weapon of choice.

"Chop Saw" Lighter, Highspeed, Most are simply the self same machine sold to
woodworkers as a "chop saw", "miter saw" etc.  Fitted with a triple grind,
carbide tipped blade a chop saw will do a super job on your type of application.

With a good quality machine, sharp blade, wax based lube etc I would expect the
cut you describe to be done in a matter of three to five seconds..tops, with a
perfect burr free finish.  The cut of part will be barely warm to the touch!!

Yes, they do make abrasive cut of wheels for aluminum..because they can sell
them..not, as you dicovered, because they work worth a tinker's cuss!!

How do I know all this?   Several years ago I too, was the proud owner of a
Contract Machine Shop!  Over a period of several years, I made Hundreds of
Thousands (Probably Millions..I was too tired ever to count!) of replacement
"after market..no name" rollers for every conceivable make, model and size of
photocopying machine ever put on the market.  Each of these required the chop
sawing of two slugs of 1" to 1 1/2" diameter solid aluminum bar and a similar
diameter of tubing.  The three pieces were friction/inertia butt-welded together
to form a blank that was high speed turned on CNC machines etc.

Using "Child slave labor" (Students)  I could expect fifteen to twenty slugs a
minute! I ran teams of two, one cutting, the other fetching and feeding stock
and carting away slugs and CHIPS!!...By the Barrel load!

During that period I plumb wore out, several high quality, Swedish made, "Chop
Saws", specifically designed for non ferrous metal cutting.  They carried a
price tag  three or four times as high as the "Home Depot..Japanese import"
brands of Miter/Chopsaws. Well over  two thousand dollars each!

I could "Kill" one in six months.. running two to three shifts, to keep up with
the CNCs, running three shifts, seven days a week...But not one died owing me
money!!  After a while I started getting replacements FREE!  The Manufacurer
used me as a destructive testing Laboratory for new developments and
improvements!

If I had relied on any other method (and believe me I tried them all), I would
have gone bankrupt in a month!

So I strongly suggest you replace that abrasive wheel with a top quality, triple
chip ground, carbide tipped saw blade that is specifically designed for aluminum
(hint..Home depot don't carry them!!) Get some wax stick lubricant...And have
FUN!!  8^)

FWIW

teenut







"Matt Stawicki (APP Leader)" wrote:
>
> First, I'd like to thank all of you who responded to my
> question. Next, I'll tell you what I did.
>
> Pete A. described the best solution, Mike G. put a name on
> it. I talked to quite a few different people and a Cold Saw
> is definately the way to go. However, I simply didn't have
> almost $500 to spend. I probably could have gotten away with
> trying to find a coarser blade for my horizontal band saw,
> but it still would have been tied up for way to long. I use
> it for many other things and I really don't want to have to
> change blades back and forth and reset my stop all the time.
>
> I wound up buying a Milwaukee brand Chop Saw.
> With an abrasive blade made for cutting aluminum, I can cut
> through the 1 1/4 bar in about 18 seconds. Beats the crap
> out of the 72 seconds it was taking on the horizontal
> bandsaw. I get almost 200 pieces per blade and the blades
> sell for under $5. The only bad part about using the
> abrasive blade is that the parts get HOT! Made the mistake
> of trying to pick one up after cutting it off and now have a
> little dead skin on the ends of 2 fingers and my thumb.
> Smooth move, Exlax!

From: Robert Bastow <teenut@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: any possible problems?
Date: Fri, 17 Sep 1999 07:40:56 GMT

I have been around machine tools for far too long (40+ years) to trust to luck
in any aspect of use.

The biggest cause of binding/breakage in any saw blade is the failure to remove
the chips you work so hard to produce.

Yes I buy good wood blades.  I buy the best tools of any kind.  If I can't
afford the best..I do without!

I find that even (relatively) cheap, say Delta's own brand, do quite well on
aluminum.  Heck the stuff isn't near as tough as Hickory or as abrasive as
plywood or particle board.

I used to buy special triple cut blades, for aluminum, on my tablesaw.  Then I
came across an industrial user that had cut over 200,000 aluminum parts with a
regular alternate top rake blade on a chop saw.  The blade was still going
strong..though the chop saw was plumb near wore out!!

Since then I use my best grade Forrest alt. top bevel for every thing..certainly
aluminum doesn't seem to hurt it one bit!!  Granted the Saw is a top of the line
Powermatic and I use hefty anti-vibration/bolster washers..but I use those for
all cutting tasks.

I think the biggest enemy of carbide blades..be it on the Table saw, a lathe or
a milling machine..is vibration or lack of rigidity causing the blades to snatch
and crumble the tips.

I would guess that very few carbide blades/tips last long enough to get WORN out
by HSMs..Myself included!!

teenut

Eastburn wrote:

> Teenut -
> 1. lucky.
> 2. skiptooth - that helps.
> 3. I bet you buy a good wood blade.
> 4. Some wood blades are tipped or flame hardened - another metal.
> 5. some wood blades are metal blades with wood teeth... ;)
>    (those are the ones I use on my 14" W/extension for slicing up logs.)
>     ( Takes a strong blade to do some logs.)
> Martin
> --
> NRA LOH, NRA Life
> NRA Second Amendment Task Force Charter Founder
> Martin Eastburn, Barbara Eastburn
> @ home on our computer oldtree@pacbell.net
>
> Robert Bastow wrote:
>
> > No Martin, I regularly cut 3/8" to 1 1/2" 6061T6 alloy with my regular 6 tpi
> > skip tooth woodworking blade on my wood working bandsaw!
> >
> > teenut
> >
> > Eastburn wrote:
> > >
> > > With a wood blade - oh .001 Al... :-)
> > >
> > > The blade is exchanged with a metal cutting type that is designed for the
> > > type of metal and also shape (hollow....).
> > > Martin