I'm in need of a jeweler's scale, but am reluctant to buy just
anything without getting some advice on this. Is there a scale for
modes: grams, ounces, troy ounces, pennyweights and pounds or
similar that doesn't cost an arm and a leg. I saw one in the Rio
catalog called Ohaus
O’House makes good scales. I don’t know that particular model, but
they are well known, and produce quality scales.
Some things to look out for, that can trip you up.
If you need a scale that’s “legal for trade”, then be sure it’s
actually stated as such.
Also, just because it’s modes may include the units you wish,
doesn’t mean it will do what you need. Pay attention to the maximums
it can weigh for a given unit, as well as the resolution. For
example, you can buy nice looking multimode scales that include
carats in the units. Some of these only weight to within a half
carat, while others, usually those having a lower maximum load, might
weigh to withing.05 carats (five points) If you’re weighing lots of
semiprecious stones or rough, perhaps that’s enough. But for more
costly goods, you need higher resolution, to .01 carats at least.
And even those may not be accurate enough, since that last decimal
place on many such scales isn’t totally accurate. For that, you’d
need a scale that goes one decimal place further, such as.005 carats.
If such a scale says it weighs to within a half point, then you can
put reasonable trust in the “points” decimal place, even if the.005
might be wobbling between.005, and the next increment up. Even better
(found on proper diamond scales, would be a resolution of .002 or
better. Anyway, you get my point. Look not for just the units you
want, but the maximum loads it can weigh and the resolution. Don’t
expect a scale that can weigh up to ten pounds, to also be able to
weigh down to a milligram or two. The other thing to point out is
that some units, while useful, might be reduntant. If your scale
reads in pennyweight, does it actually also need to read in troy
ounces? That’s an easy conversion. Same with grams to carats, if the
grams resolution is good enough to translate into the resolution you
need in carats. (for example, a laboratory grade scientific scale
might be only metric grams and milligrams. But if such a scale
measures down to a tenth of a milligram, then you’ve got yourself
one hell of an accurate diamond scale too. This can be of help if,
for example, you’re looking at scale on ebay. You might find such a
used scientific scale for a lower price than a less accurate new
diamond scale…
Hope that helps.
Peter Rowe