angel rodriguez wrote:

> Hello Marchal,
>
> Monday, July 05, 1999, 12:02:28 PM, you wrote:
>
> MvL> Hi All,
>
> MvL> I think my main frame looks very unstable, so I've decided
> MvL> to start 'all over again'.
>
> MvL> I'm thinking of making the main frame of one big upright metal
> MvL> bar (20-30 centimeters wide), not like the two upright pipes
> MvL> from the article. I think this will improve the stability of the
> MvL> device.
>
> MvL> What do you suggest, a aluminium frame or can any metal be used?
> MvL> How big should the base plate be?
>
> MvL> Any input will be appreciated,
>
> MvL> Best regards,
>
> MvL> Marchal van Lare
> MvL> -Nieuwvliet, The Netherlands
>
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>
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>
> Hi,
>
> I have some pictures of my latest lehmann at http://www.barriles.com/gardengate/
>
> Best regards,
>  angel                            mailto:angel@............
>

Hello Angel,

Thanks for the picture reference to your seismometer again.
I like the tension pivot variation you have, but I do have a
question is the BW workmate piece made out of plastic?  If
so, is there any sign yet of pressure flow/deformation?

Marschal,

Another variation of the same tension pivot can be seen at:
http://www.users.uswest.net/~psnseismograph52/page22.html
Here, John Lahr used a solid round ring as part of the pivot.
the only major difference between the two is that Angel can
remove the boom and mast, whereas John's pivot is more
involved to remove (but simpler overall, and probably much
stronger).  You haven't mentioned the pivot you use, but if it
is like the original Lehman knife edge design, it can present
problems....I'd recommend something like Angels or Johns
pivot design.

Meredith Lamb




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