4 isosceles right trangles

[cathead]

Today I hoisted the rotary table onto the mill table and made a set of four right isosceles triangles for some set up operations or
to be used with magnets for weld positioning. I happened to have a pair of these donut magnets so will likely sandwich them
between each pair of triangles and probably bolt them together along with a bit of gorilla glue or similar. The triangles were
roughed out on the band saw table freehand and fine tuned with the rotary table.
I used 3/16 hot roll as I had a chunk of it laying around to make these.


The round donut magnets have plenty of holding power so I am happy with that. The mill scale was not coming off very well
with my angle grinder so may have to get some more aggressive wheels for that purpose.

 

[matthewsx]

Looking good, you might want to leave the mill scale on there unless going for a nice finish.

John

 

[brino]

Looks good!

The ones I bought some time ago are so weak they won't even hold themselves to steel plate.....useless.

-brino

 

[FOMOGO]

Nice job. Are the magnets from speakers? Mike

 

[T Bredehoft]

The magnet looks like some i rescued from a Microwave...

 

[cathead]

Actually, they came from a gauge called Balzers. They look expensive! You can find them in microwaves as well.

 

[ThinWoodsman]

That's ... pretty ballin'

 

[cathead]

Looks good!

The ones I bought some time ago are so weak they won't even hold themselves to steel plate.....useless.

-brino

I have a feeling that because of the intense electrical currents involved in welding that welding magnets have
a tendency to lose magnetism with use. This would be especially true with SMAW(arc welding) using AC in
close proximity to magnets. Demagnetizers use a coil of wire powered by AC to perform this function so we
think we are just welding but reality we are welding and running a demagnetizer at the same time. I'm sure DC
arc welding would have less effect than AC on magnets.

Also, storing magnets on a magnetic surface will keep them from losing magnetism. A piece of steel placed
across magnet poles is called a keeper and it will help to maintain them.

 

[cathead]

A word of caution if retrieving magnets from microwave ovens is in order if you disassemble the magnetron....................................

A magnetron contains several donut magnets similar to what I used. The ceramic insulators in the magnetron usually
contain beryllium and are hazardous if you grind on the insulators and generate any dust. You can salvage the
magnets safely if you are careful and don't disturb the ceramic insulators. It's probably wise to wear some gloves
if you get into this sort of activity. The magnets themselves are entirely safe to handle.

 

[homebrewed]

The Balzers-made unit your magnets came from was a ionization type vacuum gauge. The parts exposed to vacuum probably are stainless steel. Don't know if you got that part of the gauge or not -- the actual sensor is replaceable, what your photo shows is the body that has the magnets and electronics.

And yes, when new they are expensive. The consumable part of the gauge alone costs about $150....