From: Robert Bastow <Tubal_cain@hotmail.com>
Subject: Re: How to Cut Steel with a saw?
Date: 10 Oct 1998
Newsgroups: rec.crafts.metalworking

Red Rider wrote:

> The way it works is the friction from the blade gets the metal you are
> cutting white hot and it is easily pushed out of the way as slag. The blade
> gets hot but doesn't change color, as the moving edge of the blade is acting
> against the non-moving part being cut, and heat doesn't build up fast on the
> blade.

A number of years ago I worked with a company that produced vibratory bowl
feeder systems.  The primary construction was 1/8" 300 series Stainless Steel.
All the cutting of this material was don on friction bandsaws, running at wood
cutting speeds and feeding by hand at about th speed you would feed 1/2"
plywood.  These were, in the main, large, high powered, industrial bandsaws but
we did buy a couple of asian built 14" wood cutting bandsaws for odd job
cutting.  In the interests of longer blade guide life, we converted them to ball
bearing guides..just like their bigger brothers.  The special friction cutting
blads were used for the larger machines but on the smaller ones a regular 18
tooth metal cutting saw blade was used.  Obviously,, at woodcutting speeds on
SS,  the blade soon lost its "sharpness"..probably in the first 1/4" of cutting
but thereafter it settled down to a long and successful life as a friction saw.
This usage does not strip all the teeth off as one may expect, it simply reforms
them into a shape remarkeably similar to the teeth on a regular friction cutting
blade.

I have tried this at home on my delta 14" band saw which is not yet fitted with
a speed reducer.  It works like gangbusters on steel sheet up to 1/8'' thick.  I
use regular wood cutting blades to cut aluminum up to 1" thick with great
success.  Using WD40 as a lubricant the blades last longer on aluminum than they
do on hardwoods and plywood.  I guess the aluminum is far less abrasive.

This, I am sure will work well on the tubing in question,  I would hold the tube
in a vee block in order to present the blade with a corner to cut thro' rather
than a 1" high slab of tube wall on edge.

Robert Bastow

From: Robert Bastow <teenutNOSPAM@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: any possible problems?
Date: Wed, 15 Sep 1999 04:01:09 GMT

Bob & Marilyn Tonkins wrote:

>         Among my many projects, I too am modifying a wood cutting band saw to
> cut metal.

Maybe not your particular requirements..but for anyone who only cuts sheet metal
up to 12 gauge....YOU DO NOT NEED TO SLOW YOUR SAW DOWN  from wood cutting
speeds!!

Ok..teenut's finally lost it!!

No..seriously!  The technique is called FRICTION CUTTING and is used regularly
in industry.

Fit your wood cutting bandsaw with a regular fine toothed metal cutting blade
(carbon or hss)

Rev 'er up and feed your steel sheet into the blade at about half the feed rate
you would expect to use on plywood.  Don't be shy with the feed..dont let it
dwell too much.

The blade will cut through your steel..even stainless or tool steel..like a hot
knife through butter.

After your first cut, the blade won't be up to much as a regular "slow" cutting
blade..but it will continue to work as a friction cutting blade for an extended
period of time!

Try it..you will be amazed!

teenut

From: Robert Bastow <teenutNOSPAM@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: any possible problems?
Date: Wed, 15 Sep 1999 17:38:22 GMT

Ned Simmons wrote:
>
> It depends primarily on the speed of the blade.
>
> Real friction saws run up to 10,000 FPM. Grob makes some beauties, I've
> seen them as large as 48".

Scary things ain't they..thats what we used. 15HP drives.


>It's also nice to minimize breakage as a blade breaking at 6500 FPM can be
> exciting.

Now THAT gets the "Understatement of the Month" Award.

GUARANTEED to require an immmediate change of skivvies!!

teeenut

From: Robert Bastow <teenutNOSPAM@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: any possible problems?
Date: Wed, 15 Sep 1999 17:32:06 GMT

We used honkin' great 15 HP band saws and slicing a 10" file lengthways was a
good demo of the potential!!  3/16-1/4" was possible on 300 series stainless
tho' most of our work was 12 gauge.

I KNOW a Harbor Fright type, two speed, bandsaw will do it..cause I bought one
for the lads to use on small cuts...It took too long and too much power to wind
up the big buggers for a 3 second cut.  The metal "cutting" blade that came with
it lasted about ten times longer at "Woodcutting" speed, than it would have done
at "Metalcutting" speed.

This doesn't work as well on highly conductive or soft/ gummy materials..like
aluminum and copper.  Not enough friction heat developed and what there is, is
conducted away too rapidly. It will cut, but heavy burrs are produced that hang
up and jam the feed.

In any case..I use my wood cutting bandsaw and blades to profile aluminum up to
1 1/2" thick.  There is less wear on the blade than if I were cutting plywood,
particle board or hickory!!

I am not so sure about using wood cutting blades for friction cutting..not
enough teeth/thickness to share the load of carrying the heat away.  Probably
not enough beam strength or tension to withstand the feed pressures involved
either.

NO!  I am NOT going to test it out on my $35.00 "WoodSlicer" resaw blade!!

teenut



Steve Knight wrote:
>
> On Wed, 15 Sep 1999 04:01:09 GMT, Robert Bastow <teenutNOSPAM@home.com> wrote:
>
> >
> >No..seriously!  The technique is called FRICTION CUTTING and is used
> >regularly in industry.
>
> how thick of steel can be done this way? I have seen it done with a
> woodworking blade too.
>
> Knight's Toolworks & Custom Furniture Galoot Made Products
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