Hi all,

With all the discussion on a horizontal boom/mast pivot, it
might be alot simpler to use/make another type mentioned in
the past emails.  Its based on the Sprengnether horizontals
general design and has been "revised" for use by John Lahr
on his horizontal; but it essentially is the same type pivot.

See the 5th photo/diagram down from the top of this web page:

http://www.jjlahr.com/science/psn/gldn_psn.html

For other views of the same hinge, See the 2nd & 4th photos
down on this web page:

http://www.geocities.com/meredithlamb/page022.html

The Sprengnether shown beside/with Johns seismo, in the other
same page photos uses the same basic pivot....only laid out
mechanically alittle differently.

I think its one of the best pivot innovations I know of,
and most ingenious of John to come up with the variation.
Theres probably about zero long term problems with this
conpared to other pivot designs.  Its frictionless as
John describes in his text.

Take care, Meredith Lamb


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