Austin DIY HT Projects (1 Viewer)

[Hank Frankenberg]

Mark, I've got a catalog from the magnet company where I bought a load of small neodymium magnets for speaker bafffles & grills. They have sintered and cast alnico, ceramic, neodymium and samarium cobalt magnets of all shapes. Web site: www.buntingmagnetics.com
What in the world are you dreaming up?

 

[Mark Hayenga]

I can't say, but it may possibly involve magnets, metal, and thousands of volts

 

[Mark Hayenga]

Some of those NdFeB disc magnets at Bunting look really good, I would like a larger diameter but I could definitely make them work. Another option I thought of is to contact the guy who owns www.acoupower.com and see if I can buy a neo magnet or two or three off him, they use a 6" neo magnet in their subs and he posts on several HT forums. That's actually a good bit larger than what I am wanting, but they might work too. If I could get some 3-4" OD disc NdFeB magnets with ~1" ID it would be ideal.
This is actually quite a bit of info about what I'm doing, so it shouldn't be too hard to guess, though there will be some surprises.

 

[Hank Frankenberg]

If it hadn't been for the "...thousands of volts..." comment, I would have guessed you've spawned a novel sub driver motor concept. No, I haven't guessed it - maybe because I'm thinking INSIDE the box of home audio. Hmmmm......

 

[Mark Hayenga]

The 'thousands of volts' thing may or may not work. It's just an idea right now, I haven't run the numbers yet but I may well run into arcing well before I can do anything useful with it. I've been working primarily on magnetic ckt design so far, which is surprisingly easy given modern computing (you guys should check out a program called femm, it's really nifty). When I was figuring out how to use it, I whipped up an XBL2 motor really easily and even plotted some basic B curves for the motor. Still working on getting it to generate a true BxL curve, and right now I've only been working at DC. But I'm learning more about it all the time....

 

[Leroy R]

Different metal compositions, magnets and thousands of volts, I'm thinking Philadelphia experiment.

 

[Mark Hayenga]

That's kind of funny, because I just stumbled upon a place called United Nuclear that sells huge neo magnets - 3" diameter by 2" high Neo 45 nickel-copper-nickel plated for a whopping $200 - they do have some smaller and cheaper stuff though. They look like a hobbyist/school/small lab supplier type place, so I've no idea if they're stuff is as good as they claim (I'd hate to spend a bunch of money on something that's supposed to be Neo 45 and have it turn out to suck).

 

[Mark Hayenga]

After poking around some more, I've found some much more economical options from other suppliers, one being up in Plano (CMS Magnetics) which looks like an importer (I think it stands for Chinese Magnetics Source). They've got a 2"OD 1" thick Neo 40 magnet for $16, which is almost too good to be true. They also have a neo ring and some ceramic rings which look like they are meant for the speaker industry.

 

[Mark Hayenga]

Also, for anyone who wanted to know, stacking magnets on top of each other = sucky. Putting magnets in parallel = much bigger bang for buck.

 

[Mark Hayenga]

WOW custom metal work is expensive. At these prices there's absolutely no reason to use anything other than NdFeB - it's going to be a relatively minor percentage of the whole. On the plus side, black chrome doesn't really add a whole lot to the total cost
I may have to get other people interested in this project. The per-unit cost for a typical part drops from $171 to $52 if you up the order from one to five units.

 

[Nils Luehrmann]

Any of you evil scientists need some assistance?

 

[Mark Hayenga]

Sure, hold this
http://members.iinet.net.au/~pterren/Tesla_7ft.JPG

 

[Mark Hayenga]

BTW, here's a back plate/pole piece I made in a CAD program. These are only $450ea :frowning:
http://www.hayenga.com/mark/speakers...motorpart1.JPG
http://www.hayenga.com/mark/speakers...motorpart2.JPG
That's an 8"OD, 1" thick back plate with a 5" tall 3" OD vented & radiused pole piece made out of a solid hunk of 1008 steel, brushed finish and black chrome plated

 

[Mark Hayenga]

What happened to Igor?

 

[Nils Luehrmann]

Igor? Huh? Mark... have you been sniffing toxins again?

 

[Mark Hayenga]

Dad did have cajun for lunch

 

[Jonathan DA]

Hey guys, I'm back for a few days before heading to Europe. Too bad you passed on that practical joke
Mark, Igor's headed to Europe as well (different destinations than I) so he may be frantically trying to get things done before he leaves this week. I found emachineshop.com to be kinda pricey. You might have better luck with a local shop that is looking for some extra work.
Nils, I still have your power supply here. When's a good time to get together before I leave Sunday?

 

[Mark Hayenga]

When were you guys looking at eMachineShop? For the metal badges you guys had made? or for something else you haven't filled me in on?
It is pricey, but dang is it easy to use. It's the first place I've looked at though, so I definitely need to do some price shopping.

 

[Jonathan DA]

Hey Mark, I checked out pandora.com. That site is awesome, it works much better that similar sites I've tried in the past. Nice find. It's gonna cost me money though when I start buying some of those new albums I'm finding.
Fellow music lovers, you gotta try this out: http://www.pandora.com

 

[Nils Luehrmann]