Riders (5 & 10 mg)Aluminum
wire. Note that the 10 mg riders are used on balances with
a scale with 0 over the beam center, and 10 over the pan hanger;
the 5 mg rider is used on balances with a scale going from 0
- 10 pan-hanger to pan-hanger, with 5 at the beam center-point.
Henry Hiel Chemical Company (1903) - The complete sections on 1) Balances and Scales and 2)Weights from this 521 p general laboratory supply catalog are reproduced. A wide variety of balances are featured with an emphasis on Troemner balances.
Krayer, Peter J. The Use and Care of a Balance. (1913) This is the book on setting up and using an analytical balance. It does not seem to have been superceded since its publication in 1913. It has just been reprinted (2009) and is now available from booksellers such as Amazon™. I was recently contacted by Peter Krayer's grandson,William J. Krayer, who spent some time as a youth following in his grandfather's footsteps servicing balances. Two descriptive documents from William Krayer can be found below:
Background Letter (pdf) This letter gives a bit of family history, and gives some context to balance maintenance during the peak of laboratory use of the two-pan analytical balance.
Balance parts: Illustrations and specifications for some parts commonly needing
replacement are given below. All dimensions were determined with
dial calipers unless otherwise noted. If you are interested in replacing missing parts, I have linked a set of emails describing a successful restoration of a missing chain by a user of this site as an example of what can be done - Rich
Ainsworth Model
LCB Chain balance beam Weight. 0.5000
g stainless steel: 0.540" long overall; center = 0.089"
dia x 0.190 long; shoulders = 0.121" dia. Note that the
beam has notches from 0 - 1.0 at 0.1 intervals along the beam,
with 0 and 1.0 directly over the pan hangers.
Christian Becker
Model AB-2 Chain balance beam Weight. 0.7172 g stainless steel. (Purchased in 1952. Weighed on a calibrated
Mettler electronic analytical balance 11/9/99.) Note that
with the dial reading chain balance from CB the notches do not
go across the entire beam - they are offset for better visibility
(see illustration in Christian
Becker Analytical Balances) - thus the heavier weight
than is seen in the Ainsworth balance above.
Christian Becker
Model AB-2 Chain balance Stirrup with hook.
2.9898 g aluminum body with polished flat agate
bearing surface and brass hook assembly. (Purchased in 1952.
Weighed on a calibrated Mettler electronic analytical balance
8/5/04.)The brass parts are of stamped sheet metal (0.032 in
thick) with a laquered finish. The brass "U" appears
to be press-fit into two holes through the aluminum stirrup body.
The two arrest support screws are locked in place with small
set screws. Comparison views vs. machinist's rule: Stirrup
with hook; top view of stirrup
body. Note that the pictures of the stirrup and hook assembly
show the assembly upside down.
