OldTools Archive

Recent Bios FAQ

276154 Kirk Eppler 2022‑08‑15 Re: Pricing plumb bobs. Impossible task?
The density will be higher.  Figure out the volume and weight of a normal
one (like a General), then gather the relative heft of others, calculate
the density of it, should be much higher.

There are rumors that the mercury is supposed to move to dampen the swing,
but Starrett etc never made that claim, just higher density.

Mercury is 13.59 grams per cubic centimetre

Steel is about 7.9

So if the whole thing was mercury, would weigh almost twice as much, but
would be hard to get a string around.

So guess at 30 - 50% higher weight for the same sized plumb.

This says even less, 25% for the same size

https://archive.org/details/StarrettToolsCatalogNo25/page/n64/mode/1up

Kirk in Half Moon Bay, still looking for hewing hatchets in the mess

On Sun, Aug 14, 2022 at 7:33 PM Matthew Groves 
wrote:

> JP, I know how to spin an egg to discover if it’s hard boiled or raw, but
> is there a trick to knowing which bobs are filled?
>
>


-- 
Kirk Eppler in Half Moon Bay, CA 

Recent Bios FAQ