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Subject: Re: Lehman construction
From: meredith lamb mlamb1@..........
Date: Mon, 10 Jan 2000 21:09:18 -0800


> Gentlemen,
> Well, things seem to be going along quite nicely,  but I think I've hit a
> roadblock.  I can now setup the boom for a very repeatable 11sec period,
> but I just can't seem to coax anymore out of it.  I've tried tilting the
> base with the front screw and bringing the rear boom pivot point closer to
> the vertical plane of the wire pivot.  Just doesn't seem to want to slow
> down any more than about 11sec.
> I am using a 1/2" dia.  threaded brass boom,  with a sharpened point on the
> pivot end.  This point is pivoting in a VERY small dimple at the end of a
> 3/8" bolt.  I even tried applying a small amount of lube to the pointed
> pivot,  in an attempt to reduce any friction.
> Any suggestions?
> Jim Martin


Suspect your boom/pivot junction (3/8"s bolt).  Does the 3/8"
bolt allow movement both toward or away from the front of
the mast?  Is it very secure in the mast? Another question...
what is the weight of the mass? (Its remotely possible too much
weight could be bending your boom, and influencing the period
Also, a question is of the mast; is it very sturdy or does it
bend during its swing? Its possible it needs additional
support.  Overall, if the frame/mast is built like a tank,
then the stresses have less influence.

Meredith Lamb


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Larry Cochrane <cochrane@..............>