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Im saving your magnet FAQ... Ill have to pull the speedo and look it over during the winter. Interesting stuff! Keith Keith Park Top Notch Restorations topnotch@nycap.rr.com 71 Squareback 65 Notchback 65 Squareback 75 Opel 87 Golf 88 Rx7 10th Anniversary ----- Original Message ----- From: "Jim Adney" <jadney@vwtype3.org> To: <type3@vwtype3.org> Sent: Friday, November 08, 2002 6:56 PM Subject: Re: [T3] My Notch's Tranny > On 7 Nov 2002, at 19:27, Keith Park wrote: > > > Really?? I probably should have started this up with Jim on rec.antiques > > r+p but the philco antique radio shadow meters from the 30's generally work > > so crappy now because the little horseshoe magents in them lose their > > potentcy... or this is what was explained in the past... are there other > > things at work here?? > > I'm not familiar with the Philco shadow magnets. > > Things that WILL demagnetize permanent magnets: mechanical shock, > thermal cycling, magnetic cycling. The choice of magnetic material can > generally be made to make these things stable against whatever enviroment > they are in, but poor choice of materials is always possible. > > Some magnets are very susceptable to being demagnetized by having them > disassembled. If there is another part in the magnetic path and you remove > that part, then the magnetic field is diminished. The material may not recover > when you put the magnetic material back together. Sturmey Archer dyno- > hubs are this way: If you take one apart you MUST slide the magnet off the > armature and directly onto a special keeper if you want to avoid reducing the > field by half. Magnets like this are magnetized with something in their gap > and kept there all their lives. If the object is removed without a keeper, you > may lose as much as half the field strength. This is just one form of > demagnetization by magnetic cycling. > > Some magnets can also be sensitive to having a tool, like a screwdriver, > stuck in them to see if they are magnetic. Each time this is done the field > may come down a bit, until they reach a stable lower level. > > > It doesnt stick on the pin, it comes off a little... then goes up rapidly > > between say 15MPH and 25 or 30... then behaves more normally again... > > Is your foot just heavy? Our second gear acceleration is always a bit better > than third. ;-) > > Is there anything sticky about your pivot points? I agree that this sounds odd. > > - > ******************************* > Jim Adney, jadney@vwtype3.org > Madison, Wisconsin, USA > ******************************* > > ------------------------------------------------ > To unsubscribe, E-mail to: <type3-off@vwtype3.org> > For more help, see http://vwtype3.org/list/ > ------------------------------------------------ To unsubscribe, E-mail to: <type3-off@vwtype3.org> For more help, see http://vwtype3.org/list/