Plasma cutter idea

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I've been playing around with my new plasma cutter and the first thing
that I've learned is that I will not be cutting freehand, at least not
any time soon.  So I made a circle cutting guide that works really
nicely and I was thinking about a straight cut guide, when it occurred
to me:  instead of moving the torch over the stationary material, how
about moving the material under a stationary torch?  It would work like
a table saw.  In fact, how about adapting an old table saw to a plasma

You could "rip" with it, or use the miter guage.  Cutting to a line with
a miter guage would be a lot faster than clamping a straight edge with
the right offset.  Cutting to a pattern would probably be easier with 2
hands guiding the pattern against the torch.  Hey - you could have a #5
lens fastened in front of the torch for helmet/goggles free cutting.

It could have a water pan for "swarf" collection & fume extraction would
be a lot easier with a fixed torch.  If the fume extractor worked really
well, you could use it inside!    Foot pedal arc control.  The torch
would have to be easily removed for off-table use.

Limitations: really big pieces of material (4 x 8 sheets or 20' lengths).

But I'm a newbie at this plasma cutting thing and sometimes I get
carried away solving problems that don't really exist.  What do you guys


Re: Plasma cutter idea

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Lots of people told Henry Ford he was an idiot.

I can see where long cuts and big cuts would take special prep, but the idea
sounds very logical and sensible.  Just about all you would have to do is
set up a fence.  They sell the little single roller ball bearing things that
you could make a planar surface with.  ( I can't recall their actual name
right now.)  That would allow you to do bigger things without having to have
a carriage and more support.  It would also allow you to keep it very clean,
as the slag wouldn't even get to the roller balls.

Keep us posted.

Most good things start with ideas we get while not trying to get them.  Or
at that 2 AM piss stop.


Re: Plasma cutter idea
  Greetings all,

  Great idea, Bob!  Button rollers on, say, 12" centers, 6'x6' table, torch
center mounted or better yet adjustable along one axis, 90 deg. out from rip
fence. Catch can/pan water filled under torch, exhaust pulling out right
around pan on bottom, just over torch on top.  Provided the torch was
solidly attached and you can maintain a good ground, I'd say you have a good
idea in the making.  You might even consider utilizing a belt on the rip
fence, with rollers on each end, to prevent binding or dragging.

  Best of luck,

Re: Plasma cutter idea

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The only downside I see to it is the space that it consumes. But, if you
have plenty of space, and do enough of that sort of work to justify it, then
go for it.

You might also consider making up a straight guide that clamps to an
existing workbench. Put it on when you need it, put it away when you don't.
Let us know what the outcome is.

Re: Plasma cutter idea
Jon wrote:
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When you take up that much space with the rig (and effort building it)
you may as well go all out and build a CNC plasma table given the
relatively low cost to do so these days.

Pete C.

Re: Plasma cutter idea
but its a lot easier moving the torch (it only weighs a few ounces). once
you get into larger pieces a CNC setup would be preferred. i'd rather not be
trying to manhandle a 4x8 sheet of anything, etc.

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Re: Plasma cutter idea
A plasma tourch will cut off your finger as easily as a table saw or
band saw.  I would put some kind of guard arount the torch head above
and below the stock.


Re: Plasma cutter idea

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Not as messy, the wound is cauterized.

Re: Plasma cutter idea

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LOL, Doesn't grab your glove and suck your arm into the arbor either.
Hey, they should advertise that!  "PlasmaBurn 2000, Economical
cauterizing feature saves on trips to the hospital."


Re: Plasma cutter idea
Bob Engelhardt wrote:

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Doesn't sound that stupid at all! Not to say that I love the idea. Depending
of the size you intend to cut.
Only problem needing some more care is moving the work around. Have you seen
the tables of CNC nibblers? They use brushes (plastics, cheap!) and it is
very easy to move heavy sheet metal around.

***      The lowcost DRO       ***
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Re: Plasma cutter idea
Great idea except that it seems like a radial arm saw approach would be
better.  Just replace the saw/motor with the torch and replace the table
with a water tray.

That would allow you to keep the torch at a constant height above the work
piece and it's also a lot easier to move the torch than a heavy piece of

Eventually you could even add a drive motor, something as simple as the
motor from an electric drill to drive the movement of the torch for nice,
uniform cuts.

Best Regards,
Keith Marshall

"I'm not grown up enough to be so old!"

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Re: Plasma cutter idea
CNC is not in my future - the $800 I spent on the plasma cutter was at
the budget limit.

I don't generally cut large stuff, so if & when I do, a special set up
is acceptable.  I'd like the everyday small stuff to be convenient.
Taking the cutter outside & dragging out a cutting table is the major
inconvenience that I'd like to change.  But having it inside really
depends upon good fume extraction, which is much easier with a
fixed-torch cutter.  I plan on some experiments with fume extraction.

Today I cut a 9" square out of a circular piece of 3/16" mild steel.
This is typical of my cutting jobs, so a table-saw sized set up would be
appropriate.  Another typical job is cutting pieces out of PC cases,
also small enough.

I found that microwave oven magnets will hold down a cutting guide, so
that's a problem solved (having to clamp down the guide).  The work
itself still needs to be clamped & avoiding that would be convenient.

For now I'm going to build a quick-and-dirty cutting table (bed frame
angle) and get some more experience with my cutter.  I'm kinda' keen on
this idea, so there's a good chance that I'll build it, someday.  If &
when I do, I'll be sure to show it off here.


Re: Plasma cutter idea

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Keep us informed of your progress!

Your idea is, to say the very least, intreguing.

Re: Plasma cutter idea

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would be
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You may find that those powerful magnets bend the plasma and kink your


Re: Plasma cutter idea

"Andrew Mawson"  wrote

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I was wondering about that.  I know in welding, magnetic fields play havoc
with the arc.


Re: Plasma cutter idea
Andrew Mawson wrote:
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I haven't noticed that yet, but it seems plausible.  I tried magnets
once as a work holder for stick welding and that arc was definitely
affected.  With plasma cutting, the speed of the air flow would diminish
the effect.  I should try some experiments, unless somebody else can
speak from experience.


Re: Plasma cutter idea
Bob Engelhardt wrote:

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I just clamp on straightedges and move the torch. Today I had to make a 3-sided
piece from angle iron. It had 2 corners which needed to be radiused. I used Mike
Graham's method and made up a little jig from 1/4" plywood. Worked fine. Does
it look laser cut? No. Can anyone tell after it's been welded? No.



Re: Plasma cutter idea
Grant Erwin wrote:
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Magnets are nice: they don't need access to both sides like a clamp
does, and the straightedge position is more easily adjusted with them.
For the same reasons, magnets are nice for holding the work to the
table.  This is for thin, flat (sheet) work.  Doesn't work so well for
angle iron, etc.


Re: Plasma cutter idea
You should see what a magnet does to DC TIG.

I have no doubts that magnets near a plasma stream will bend it from its
normal course. This is how they move the arc in a tv tube as well.

Bart D. Hull
Tempe, Arizona

for my Subaru Engine Conversion
for Tango II I'm building.

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Bob Engelhardt wrote:
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Re: Plasma cutter idea
Regarding fumes:  The object (I presume) is to keep from breathing them, and
I would guess the cutting table is below 'nose' level.  May I suggest you
first determine if the fumes are heavier (or lighter) than air.  Why?

I was once in a 'nasty' environment where a lot of effort was made to
exhaust fumes from a molding process.  The mold press sat on the workshop
floor and you could easily see the fumes falling almost straight down.  Yet
all the exhaust effort was being made to remove the fumes at ceiling level
(approx 12 to 14 feet).  Needless to say, the press attendants were always
in a continuous flow of the fumes.

The 'engineering' was already done, the building was built specifically for
the purpose, and......

I have no idea if fumes created from cutting are heavier than air, but
intuition tells me they probably are.  If so, a ground level exhaust system
might be something to investigate....

Good luck,
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