Re: Cutting torroidal cores

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Ben,

I have used a cobalt tipped hack saw.  Hard work, but the cobalt does not 
dull and stays consistently sharp as you gnaw through.  Wrap the thing with 
good tape before you start to hold it together.

A typical metal cutting bandsaw blade just went dull after 1/4 inch.  The 
steel in the core is not "soft" (fancy silicon steel).  An oil bath pro 
machine may have much better luck.

You may consider just getting a new core with the slot already in 
it.  Alpha core has very reasonable priced stuff!!  I would not be 
surprised if a brand new split core cost less than having a pro shop cut 
the one you have.

http://alphacore-dot-com/

http://alphacore-dot-com/cores.htm

http://alphacore-dot-com/stcores.htm

You have to ask about split cores.  Alpha also have fancy tape and other 
general items for this work.

You may also consider WaterJet cutting.  A very cool thing if there is a 
WaterJet capable shop near you.  WaterJet will cut through just about 
'anything' from a tomato, glass, up to 8 inch military grade 
titanium.  Cores may be a problem since the high pressure water may tend to 
tear the laminations apart.  I just had some titanium parts WaterJet cut 
and was very impressed with how versatile the process is.

http://hot-streamer-dot-com/Ti-Tan%21%21/WaterJet/DoneParts.jpg

My parts were "thin" but they were doing very thick titanium there at the 
shop for a local contractor too.  It's stunning what WaterJet can do!!

http://www.dcwaterjet-dot-com/photos.shtml

Might be great for rotors, cutting tungsten, or even cutting primaries out 
of sheet copper.  It is a fully computer controlled X-Y-z thing although 
the latest machines are five axis...  If anyone ever gets a chance to see a 
WatetJet machine, it is a MUST see!!  A 55,000PSI WaterJet, 0.030 mill 
thick traveling at 1000 meters/second.  They add garnet powder to the jet 
to cut through metals and such.

Of course, check with the people at the shop.  They may already have the 
"obvious" solution figured out :-))

Cheers,

         Terry


At 04:46 PM 1/18/2003 -0800, you wrote:
>Hi all,
>   Does anyone have any suggestions on how I might go about
>cutting a 1/2" wide slot in a torridal core? (the kind that
>you find in variacs) I need to cut a slot all the way
>through to make a "c" core so that a metal disc can pass
>between the poles. The cores are made from soft iron strap
>that's been coiled. They've also got plastic formers around
>the inside and outside. I've heard mention that they tend
>to come apart when cut... Is there any way to prevent this?
>I've got access to a really good machine shop..
>
>Thanks for any help!
>
>Coiling In Pittsburgh
>Ben McMillen