A compact DIY cyclotron package solution.

[JohnCuthbert]

Very impressive.
I don't know about building a cyclorton, but you might have the start of a DIY NMR spectrometer there.

[Todd Massure]

Chris,

It seems to me that without the studs it might be possible to leave the magnets in place on one plate and slide the other plate on and off for access as needed. From your experience does that seem possible?

Todd

[Chris Bradley]

No. Not at all. You mount the magnets with the same pole all facing one way. So once you've got a concentration of them, then they'll twist and jump right off the spot given the slightest inclination so as to jump onto the magnet next to it, if you only have one plate. With both plates facing each other, the first one comes in and snaps the plates into a position which holds them apart at a given distance, so the next ones then slot in without being able to twist and jump over. You loose the flux path to the centre if you try without the two plates together, which means the magnets no longer 'feel a contentment' to stay where they are.

Also, even if you could hold them down somehow (I was originally thinking to drill snug-fitting holes in a piece of teflon) with that many magnets the next plate would get so far then I reckon you'd not be able to budge it any further.

[Todd Massure]

If one was willing to be locked into a permanent configuration, maybe it could first be assembled as you have, then, by sliding them around some, add a thin layer of epoxy between the magnets and one of the plates. After the epoxy cures, then perhaps the other plate could be slid on and off (?)

Todd

[Chris Bradley]

I still don't think you'll be able to move that plate easily. With that set of magnets, the holes didn't line up on the plates and I had to hit the whole assembly like a hammer on the floor just to budge them a millimetre or two at a time. It was really very rigid. If you did that with a plate sticking out after getting stuck on a couple of the magnets at the edge, it'd probably flip off, or something else dramatic. Besides, you suggested a removable plate for access - wouldn't epoxy-ing everything make access less flexible? I guess you could try all options, depends on the application. This should suit my purposes.

[John Futter]

Chris
If you put the nuts on the inside you can use them as a jack to slightly seperate the plates to make moving the blighters easier.

also an aluminium plate with drilled holes to locate the magnets fixed to the steel pole pieces -plastic /brass 316 Stainless are also suitable

[Chris Bradley]

John Futter wrote:
> If you put the nuts on the inside you can use them as a jack to slightly seperate the plates to make moving the blighters easier.
I am not sure it would, and I would not recommend anyone tries. (You can if you like, of course....) These came out very easy, the one-stack a little more fiddly only because that was just a single finger's width, hence limiting force you can put on them. (I got the blood blisters from re-packing them after removal, not from assembly/disassembly!!) Once you hold one and just pull in one, clean big movement to fully clear the edge, there is no problem at all. If the plates were separated by more than the height of the magnet then I could imagine they could easily twist and jump as they clear the edge.

Reporting magnetic field and uniformity is one aspect of what I've written. I'd say of equal substance is this ease of assembly - providing the plates are somewhat retained by a separation around the height of the magnets, all goes very smoothly. There is so much force in these things that to get 16 of them all together in one assembly with this much ease came as a surprise. If you've ever tried to put just a half-dozen on one plate and move them around/close, you get a feel and a big respect for how much force/damage these can apply.


> also an aluminium plate with drilled holes to locate the magnets fixed to the steel pole pieces -plastic /brass 316 Stainless are also suitable
That was my original intent, to locate the magnets into a little recess. But this would make the assembly process I've described not possible. These magnets stay where they are yet are straightforward to push around while in the assembly. They become 'very well behaved', considering. Therefore, the purpose of the studs is merely to provide just a little extra clamping force and a little extra confidence that they'll stay put, though they did anyway without the studs clamped up.

I absolutely do not believe you could safely assemble the part by hand, as pictured above, by lowering a plate down on top of the magnets, nor sliding across a plate (As Todd has suggested). One or other would be required if you create a recess for them to fit in.

I guess the magnets feel a good flux circuit into the plates because those plates have a relatively much larger area to cross back to the opposite pole of the magnet, and so they have no incentive to do anything else but hang on to the plate they are nearest. If you do anything that means they no longer have a plate in direct contact, then they'll probably find the pole of another magnet more attractive and wiill jump and twist if they can.

If anyone wants to try a different assembly technique, then I'll be interested to hear. Just think safety and wear eye-protection of course. These things can literally start 'twitching' and a ms later have jumped a metre whilst building up a shattering momentum in the process [and the 'shattering' is either magnet or bone, just depends what's in the way].

[morgoth31]

just fyi on teflon under high stress it tends to flow out of the way if you put 2 magnets one on each side the teflon will slowly squeeze out of the way. Know someone who worked on the starfigter jet in the airforce and they had issues under high g of the wires migrating out of thier teflon sheath and shorting to each other but they would spring back after and made them very hard to find till they had to cut them apart and found the thinning of the walls.