From: jack@ccsf.caltech.edu (Jack Stewart)
Newsgroups: rec.woodworking
Subject: Re: Anyone cut metal with a circular saw? (WARNING)
Date: 26 Jan 1993 01:30:19 GMT
Organization: CCSF Caltech, Pasadena, CA
Distribution: world
NNTP-Posting-Host: laguna.ccsf.caltech.edu

In article <14340021@hp-ptp.ptp.hp.com>
keith@hp-ptp.ptp.hp.com (Keith Millar) writes:

>I have this great idea that I can put a particle metal cutting blade in my
>circular saw and cut metal pipe and box steel  and sheet steel ( <= 1/4 inch )
>
>Is there any reason why I shouldn't? Are regular circular saws (mine is a
>black and decker trade 1/4 hp) able to handle the job? I was thinking that
>perhaps the hot sparks or wrong speed might be a factor.
>

I am distrubed with the direction that this thread is taking so I
thought that I ought to put in my $0.02 worth.

It is NEVER a good idea to use a tool for a purpose that it wasn't
intended or designed for.  Most (i.e. average quality) circular saws
are designed only for wood (some are really only adequate for soft
wood).  The RPM, torque, and HP power on the average circular saw are
wrong for metal.  Using the wrong tool for the job is what causes a
lot of accidents.

I have never used a circular saw for cutting metal.  The thought never
crossed my mind.  I have done a lot of metal work (Mill, lathe,
grinders, etc.).  Most Mills and Lathes using carbide steel to cut
with and have very low RPM's depending on the material (400-1500RPM).
Most of the Grinders that I have worked with run at 10000-12000 RPM
and do an adequate job of cutting metal (especially with the correct
blade).  I have also worked with Tile Saws and I would expect the
design of a good metal cutting saw to be similar (i.e. water cooled).
By comparison, a circular saw is poorly designed for cutting metal.
The blade guard only gets in the way of cutting.  The circular saw
doesn't cool the blade (or the saw itself) fast enough.  And the
bottom plate isn't right for keeping the blade at the correct depth
(Metal particle blades wear out fast).

Having said all of this, I should also add that the metal particle
blade is probably one of the safest on the planet.  I have never seen
one shatter and there is not a lot of damage that a metal particle
blade could do if it does shatter.  The blade on a Tile saw, which is
very similar to a metal particle blade (expect that it is a diamond
particle and a little wider), is so safe that you can put you finger
up to it while it is spinning a full speed.  If you still want to cut
with a circular saw - check with your saw's manufacturer.  They (or
their lawyers) should be able to tell you if their tool is up to the
job.  Some of the better quality circular saws *might* do an adequate
job.

Also look at what sort of metal you are cutting and how much you are
cutting.  If you do a lot it might be worth investing in (or renting)
specialized equipment.  Otherwise there are a number of hand tools
that do a reasonable job (i.e. Hacksaw, Tin Snips, Pipe Cutter).  BTW,
with a Hacksaw, you job will go a lot faster if you have the right
sort of blade in it (and it is sharp).

In article <16B5E12A88.EPLUS17@vmd.cso.uiuc.edu>, EPLUS17@vmd.cso.uiuc.edu (Richard Engelbrecht-Wiggans) writes:
> Since then, I have invested in a more expensive
> (Milwaukee) saw and it cuts through that angle
> stock as if it were butter.  I am however concerned
> about the possibility that all the particles
> created by my metal cutting might have an adverse
> affect on the saw's bearings etc; does anyone know?

A good quality saw (such as a Milwaukee) should have sealed bearings
so the damage shouldn't be too bad.  However does the air intake on
the saw have filters?  If is doesn't then you could be spraying metal
particles all over the motor.  Metal particles can also do a number on
your lungs.  Most masks will do a reasonable job of protecting your
lungs.  Ear Protection is also really good idea when cutting metal
(Grinders are LOUD).

This is just my $0.02 worth.  I thought I should inject a note of
caution.

---Jack

-- 
Jack Stewart                                     E-Mail: jack@CCSF.Caltech.EDU
Caltech Concurrent Supercomputing Facilities,     Phone: 818-356-2153
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