"Mark Rand" wrote in message
...
On Mon, 14 Sep 2009 09:35:10 -0400, "Ed Huntress"

wrote:



Hey, here's something curious. I just tried this, and got funny little
drops, much smaller than I would get with an eyedropper, for example.

I took a 30-unit syringe, filled it with water, and counted the drops in 5
units. I got 11 drops -- close enough to 10 -- but they were really teeny.
These were drops that would detach themselves and free-fall as I held the
syringe point-down; just ordinary drops.

That's exactly 1/10 the size you're describing -- one drop from this
syringe
is 5 microliters. I see from some references online that this is the same
size as a drop of water dispensed from a Pasteur micropipette.

So is the size of the drop that dependent on the opening from which
they're
dispensed? This was a 30-guage needle. I'd have to mike it to see the
size,
but it's *really* thin.

Might get smaller if you ground and lapped the end square. Or not...

I'll bet it would get bigger. I'll try it, but not now.



PS Are you throwing the things away after only one use? I get a couple of
weeks out of mine.

I don't use them at all anymore. I have a pump. But I typically used them
three times. The old 28-guage ones lasted longer. 29-guage is my favorite.
With the callouses I have, the 30-guage sometimes bends right over at a 90
degree angle when I try to push it in.

I used to use them until you had to screw them in. d8-)

I have sharpened a few, when I was in a pinch, on a black hard Arkansas
stone. It works pretty well.

--
Ed Huntress



Mark Rand
RTFM