Hi, Probably the easiest way is to find a compass with the same size needle that you want, disassemble it to get the needle and pin bearing. And to make your own housing for it. Making a bearing for your own needle may be hard without a lathe.
Regards, Roderick Wall. From: JOHN DAVIS Sent: Sunday, July 08, 2012 6:34 PM To: Morgie Terwilliger ; [email protected] Subject: Re: making a compass Hi John B, Your suggestion of using a piece from the mainspring of a clock for a compass needle is quite a good one - I have done this. It needs to be tempered by heating and then allowed to cool slowly first. However, the disadvantage is that the material tends to be rather thinner than is ideal (0.3 to 0.5 mm seems to be normal) and so there is less 'magnetic moment' when the needle is in place. This makes it more sensitive to the 'stiction' of the pivot. Regards, John D ---------------------------------------- Dr J Davis Flowton Dials --- On Sun, 8/7/12, Morgie Terwilliger <[email protected]> wrote: From: Morgie Terwilliger <[email protected]> Subject: Re: making a compass To: [email protected] Date: Sunday, 8 July, 2012, 0:40 John's ideas are all right on. John mentioned a piece of hard steel. I wonder if a piece of clockspring would have the right properties. You can take a clockspring out of the drive drum of a junk windup clock, and at least the outer coils can be straightened out flat. I've seen magnetizing coils. They are air-core solenoids (helical coils) of heavy gauge wire and they are energized by capacitive discharge using capacitors such as are found in photo flashes (strobes) Best, John Bercovitz -------------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial -------------------------------------------------------------------------------- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5117 - Release Date: 07/07/12 ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5118 - Release Date: 07/08/12
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