Toroid Cracking for Gaps

What's a nice way to break a toroid? I need a paperthick 0.1mm gap..

Vice + hammer?

Maybe there's a cleaving method? Like cutting diamonds?

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC
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Vice + hammer = shatter.

Maybe a dremel with a diamond cutting wheel? And prayer.

Ed

Reply to
ehsjr

Sounds better than gluing a bunch of toroid bits together like a puzzle.

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

100 microns is just about exactly the thickness of a piece of paper--much thinner than you could do with a Dremel. If you cut it in half carefully with a saw and putting it back together with epoxy, you can adjust the gap with a feeler gauge or just by using the inductance. I'd probably build an oscillator with a known (large) C and adjust the bond line thickness until the frequency came out right.

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

Build an oscillator!! No way.. :P I'd rather use my cheapo china box function generator and set up an impedance circuit. Probably an insertion loss type of circuit.

By any chance do you know a long lasting glue for ferrite?

Superglue? Silicone? Locktite ?

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

are you building a 'head' for recording/playback of magnetic media or can't you get a less-dense toroid (with distributed gap)?

Um, maybe try scoring round it with a file (or a diamond?) then heating the cut with nichrome wire.

Reply to
Jasen Betts

Use a super thin dremel cut off blade, make two slices and gap is now double whatever your gapping medium is (fish paper). Cracking only one cross section you will find nearly impossible to do.

Reply to
Archimedes' Lever

Yes

No, never.

Ambiguous.

No. Not unless pureed and dehydrated.

Reply to
Archimedes' Lever

Use a pot core. They have available with air gaps.

Leon

Reply to
Leon

ha ha...*groan* :P

Loctite makes anaerobic adhesives. The nice about anaerobic adhesives is that excess can be wiped off after the adhesive has cured. Loctite brand threadlocker is common in hardware stores over here. It's generally used to keep bolts from getting loose.

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

Power inductor. There's dc.

The gap can be anywhere.. I'm guessing if the toroid broke in 2 bits, gluing it back together will a thin glue might provide a 0.1mm gap.

Bummer...No nichrome in the junk box.. However, I wonder if scoring could help shearing the toroid with a hammer.

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

Oh well..thought I could snap the toroid in half with no loose little bits where it cracked. I suppose the toroid acts like glass... Guess you've tried snapping toroids.

Dremel will be a pita.

  • Ferrite dust and mess. (It's cold outside!)
  • Noise
  • Requires excellent blade control.

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

I wish.. But due to: Max height: 8mm f: 800khz ampsDC: 1A ampsAC:0.1A L: 400uH

In this case, gapped ferrite looks better than pot core.

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

If it's ferrite or powdered iron, it's already got a gap - it's distributed between the grains of the material.

Rather than cut your toroid, you should buy one that has the right characteristics for your needs.

Good Luck! Rich

Reply to
Rich Grise

Rejoining of a 'cracked' toroid will produce an uncontrolled gap dimension. Small pot cores are available with a 'gapless' polished interface that can be corrupted as required.

A minimum-height toroid is one laid on it's side, without an ID or OD restriction, allowing for increased turns of higher-current wire.

What's preventing you from using a larger gap? Commercially available gaps will produce Al values typically less than 80nH/T in ferrite toroids.

Ferroxcube, Magnetic Metals and Ceramag have all marketed pregapped toroids.

RL

Reply to
legg

No, works this way: Score, place in vise (with Kapton tape protection), take hard piece of wood, tap with hammer ... tchk ... catch the chopped half before it hits the garage floor. Takes a lot of practice though.

:-)

--
Regards, Joerg

http://www.analogconsultants.com/
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Reply to
Joerg

That would be the major challenge. I never managed to do that reliably. The tile saw kind of worked but the diamond blade was too worn after doing two bathrooms and >1000sqft of floor space in porcelain.

The vise and tap method scored higher yields but also produced quite some scrap.

[...]
--
Regards, Joerg

http://www.analogconsultants.com/
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Reply to
Joerg

Good point..

I don't trust my electronics design/math.. I make lots of mistakes. I'd like to snap what I have and experiment to see if all's well.

I already have two ungapped toroids.

2 chances to crack'm and glue'm. I'd like to put'm to use.

If I mess'm up then I'll check out gapped toroid in production.

Actually, I should just jump to using gapped toroid but I'm still learning magnetics and would rather experiment with parts on hand.

I already have a huge collection of wrong parts ordered..

Too many times that I clicked 'order' and changed the design 10 minutes later.. :)

D from BC myrealaddress(at)comic(dot)com British Columbia Canada

Reply to
D from BC

Also without a gap. Since it is a two piece construction, no gap is better. That way, the circuit designer gets to choose the gap.

Whatever is used to gap it times two is the gap.

Reply to
Archimedes' Lever

Thanks! Good to know that someone has done it successfully. :-)

Ed

Reply to
ehsjr

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