Barry, I have given some thought to making a new coil for a speaker magnet, but as I said, I haven't done it yet. However, I would not attempt to dismantle the magnet, mostly because getting it back together would be difficult, and also because it would permanently weaken the magnet (I've had some un-framed, ie no keeper shunts, ceramic magnets go completely dead hanging by themselves on nails). The problem is to get the OD of the magnet center pole. Of course, measuring it with an (electronic) caliper works; I bought an extension points kit for mine that accurately probes the magnet gap of even a small (4") speaker magnet. The extension probes are slightly magnetic but manageable. Knowing the OD, I can create the form by wrapping layers of 1 mil aluminum tape around a wood dowel, or you could use a lathe to make the form, or find the size of anything cylindrical at the store. Plan B: I wrapped some thin (2 mil) brass foil sheet (ACE hdwe) around a pencil to make a tight coiled cylindrical spring. Then I gently expanded it as I slid it around the magnet pole, and once it seemed square and smooth fitting, taped the overlap ends. Later I soldered both the inside and outside, and added another few layers to build up to the clearance I wanted of about 0.032" (1/32"). I presume that liquid nail polish works OK for distinguishing the layers as a coil is wound as long as it stays thin. I used the correcting tape because it was handy, since I found that it is easier to remove from the computer screen than white-out. Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>