Hi James,
Good deal on the hinge working for your vertical!
As for the curtain bracket test vertical seismometer; as is, with short further tests of it today; I can vary the period from
about 1.6 to 1.95s by just screwdriver (releasing and clamping) moving the boom bracket forward away from
the mast (longer period, but less mass allowed) or, backward toward the mast (shorter period, but more mass) on the two
spring pivot hinges; but, the amount of mass weight allowed also varies with the change. Curiosity says: ~ try a
new longer pivot hinge/s and see what that yields. As is; the mass oscillation motion looks very nicely harmonic,
and it visually responds to indoor air drafts and floor/table induced walking/weight tilt...which is in itself is quite
encouraging, but it is obviously only a very crude indication of its "sensitivity". Actually; I was expecting a much
shorter period range than this initially.
Until I try other arrangements suggested by Chris; I've no real idea of whether its possible to get more than ~ 2
seconds; time and tests will yield whatever. Theirs even a dual ball pivot arrangement one could try out which might
be the simplest but very efficient pivot. There could very well be a variety of models that might be amateur useful.
Take care, Meredith
On Sat, Aug 30, 2008 at 5:32 PM, JAMES ALLEN
<jcallen1@...........> wrote:
Hello Meredith,
I received the spring material today and installed
it into my Spregnether vertical and the unit centers perfectly. Thanks for
your assistance and the bronze hinge material. The test bed vertical made
with curtain brackets and flat spring material seems very interesting and within
the capability of someone inexperienced to make. Do you think you will be
able to get #3 up to 3 to 5 sec.?
Thanks again
James Allen