Magnets! Magnets! Magnets! 🧲 ( R&D )

Last I was taught. 4 hours without blood flow before real issues start. I doubt they would have enough pull, through clothing, for it to be an issue. It would start to itch and get unbearable before real damage would occur I feel. I would be more concerned about having an MRI and getting burned jnternally.

I will get a sensing magnet, in my finger, as I can tape it down. Still looking for thT diamond coated one, anyone have a lead?
No? Go figure.

I have huge hands, I could comfortably fit the XG3 in my fingers near the proximal phalanx bone. (Middle bone) but still not sure if it is worth it. It would be better for tricks there I feel.

Ahh, Michael Reeves and the trigger me Elmo… Good times

I have 2 magnets from Steve Haworth implanted in the fingertips, for several years. No problem with them, they buzz nicely with motors and anti-theft gates in shops, but I can’t lift a lot with them. A few nails or needles, 1 1-eurocent coin (only with 1 of the 2 magnets, the other one has migrated too deep), …

Any idea what he was using? I didn’t ask at the time.

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I pulled my 20 minutes number from Haworth’s Magnet FAQ

I’m getting my Haworth next Thursday, if all goes well. One of my friends wanted to get chipped, but was looking to go through the experience with someone else, figured it was time for another implant while I wait for the Apex. I’d been waiting years for something like a reliable TiN, but any magnet is better than no magnet.

Haworth? He uses Nickel plated N52 magnets coated in silicone. It’s also on the FAQ linked above

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Indeed. Here are his magnets.

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Rosco brought this up in another thread, and I thought it deserved to be here.

Basically rare earth magnets in a laser welded titanium “can”.

Ah yes sorry, I should have posted it here maybe. TBH I was more interested in the wetware part of it (anchoring method to the muscles) than the magnets themselves. But yes, I suppose it belongs here.

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So why not a flat one? I’m thinking of a magnetic film (0.1-0.3mm) in a flex like format. If the biopolymer used in the flexnext for example can be made thin enough the volume ratio might be good. And it sounds easier to coat :man_shrugging: I don’t know if neodymium can be made thin enough though, or maybe in a pouder form to keep flexibility? Also where would the poles be?

Good thought, but that would be tough. If you could get someone to fabricate a sheet like that at N52 strengths, it would be very brittle. This could cause sharp edges to perforate the biopolymer, and the now multiple separate magnets would likely repel each other and pull the implant apart.

Also, the strength would be negligible. The thickness of a permanent magnet in the axis of the dipole plays a much greater role in the field strength than the width, because all the aligned domains are reinforcing each other. K&J Magnetics has a good calculator. Outside the skin (~4mm away) the field strength would drop off to less than 0.05lbs. (0.8mm thickness is the smallest they make)

That’s if the pole is on the face, also does it really matter for sensing?

Can they be ultrasonic welded? I know little of titanium.

I know little of ultrasonic welding.

Titanium is a grey-ish metal. It burns EXTREMELY hot. But can be kinda hard to ignite. Very strong, and much more flexible / elastic than it would seem given it’s strength. Back when I was still machining, I kinda hated it. You could run a reamer down a hole, and get a hole smaller than the reamer. The Titanium would expand some as the cutting edge pushed on it, and close up behind it. The same could be said of facemilling / endmilling, etc. Always had to take lots of spring passes if you were holding tight tolerances.

I had to machine a pure tungsten part once. Nothing fancy, just a small cylindrical counterweight a few millimiters in diameter and in length. That turned out to be a whole afternoon job. Titanium felt positively easy compared to that stuff…

not likely… usually the horns for such things work great with plastics, polymers, etc. but I’ve not really heard much about welding metal, especially to other metal.

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i put an xg3 in the tip of my left ring finger, just to the side of the gripping surface. Very worth it in my opinion.

For sensing?

Speaking of sensing Amal, out of curiosity, can you give us some details about the construction of the reputedly “not that good for sensing” xG3 vs a proper sensing magnet? In particular, the mass of the magnet proper vs the whole (or the glass alone) and the diameter of the magnet vs the diameter of the glass?

I’m curious how much - or how little - extra mass / extra distance from the magnet it takes to dull out the sensations.

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How sensitive is it?

Somebody WILL correct me, I’m sure. But…

I don’t think you’d get good sensing from an uncoated xG3. (ignoring safety for this ex.) The coating mass hurts it to be sure, but the overall mass is too high to be sensitive to the relatively tight rapid vibrations in magnetic fields caused by A/C power. It’s the old woofer vs tweeter argument.

In other words it’s not just the magnet mass vs coating mass ratio that’s the problem.

The total mass needs to be low enough to get a good vibration going. The coating becomes a problem with low mass magnets because it eats up a significant portion of the low mass, leaving not enough room left to contain a sufficiently powerful magnet.

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The diameter of the glass is 3mm and the diameter of the magnet is 2.4mm. The length of the magnet is 12mm. The glass itself weighs 0.09g and the finished xG3 with magnet and resin weighs (on average) 0.73g

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Thanks!

It strikes me as if it’s not so much the performance “drag” of the non-magnetic bits (glass and epoxy) as much as the size of the magnet itself that makes the xG3 less suitable for sensing. It’s significantly larger, and therefore has more inertia, than a bona fide sensing magnet doesn’t it? Wouldn’t it be possible to encase a smaller magnet in glass, or is it too difficult technically?

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