My 0.02:
Wow! This is a horrible problem. I've had that critter apart and would
rather do anything than try to "recalibrate" a magnet. Several variables
come into play (think age -- bigtime!):
What's the original magnet field strength in Gauss?
How many Joules in a capacitive discharge through the magnet does it take to
get it to where it belongs?
How do you measure what you've got to start with? And what you're finished
with?
What's the precise distance from the "cup" attached to the needle-spring
assembly to get the right coupling?
What's the restoring force in the spring that's needed? (It's really old--
that's got to be a fun measurement).
Since I'm in a ground-up restoration mode (my speedo crapped at about
130,000), my thinking is more toward a well-known set of gears off the
tranny driving a rotary digital shaft encoder, then counting the pulses. In
other words, all electronic, pretty much what (I think) more modern
instruments do.
Anyone interested?
----- Original Message -----
From: <garywinblad@attbi.com>
To: "Steve Laifman" <SLaifman@SoCal.rr.com>
Cc: "Tiger List (Tiger List)" <tigers@autox.team.net>
Sent: Monday, September 16, 2002 7:02 PM
Subject: Re: Speedometer gear - got one for 3.07s
> Gary,
>
> While your advice may be consistent with aged parts,
it is not
> consistent with completely re-calibrating the
speedometer needle for a
> new gear train. That was the intent of the previous
posting.
>
> Steve
>
Well, yes that is true.. it only addressed the re-
magnitizing problem.. I don't have a magnitizer handy on
my workbench.
Gary
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