Restoring a badly damaged late 1950’s analytical balance.
This project started back in the year 2001, two decades ago when I came across an Ebay listing for a working Stanton Instruments B15 analytical balance.
I had just finished restoring a Stanton Instruments B19 balance which was very similar to the model B15, so I thought it would be a fun project.
The balance was located in England and somehow took three months to ship and reach my doorstep.
Unfortunately, the seller P.J.Manison from Swansea, United Kingdom, assured me that he was experienced and would properly pack the scale for international shipping.
It gets worse as I remove the single sided cardboard wrapping and masking tape from the case to find no extra padding under the wrapping.
The shipper for some unknown reason decided to leave all the weights in place, along with the balance beam and pans with no means of securing them. To make matters worse the shipper decided to place the heavy power transformer and lamp assembly, wrapped in a few layers of newspaper inside the case to bounce around during its travels.
Miraculously, somehow only one piece of glass was broken since the only protection for the glass windows was a thin piece of corrugated plastic sign board taped on the outside areas that had glass underneath. The case also took quite a beating, splitting solid wood and plywood.
After receiving the shipment, notifying the shipper, and sending photos, he denied all responsibility and blamed the damage on the carrier.
Also since it had been more than three months since the initial purchase, Ebay said it was too late to claim a refund or return.
At this point I didn’t know what I wanted to do with this balance. I did know that it would have to be dissembled and cleaned before repairing it, or parting it out.
Shortly after cleaning and documenting all the pieces of the B15 balance, I moved to a new job several states away requiring me to properly pack-up all the pieces for the move.
For nearly two decades and another move the B15 stayed securely packed, patiently waiting for it’s time.
Then came 2020 the year of COVID-19 and extra time to work on nearly forgotten projects.
Stanton Instruments was founded in 1946 by Henry Morton Stanley and Albert W Harrington, in London, England. Stanton Instruments (SI) continued building precision balances until 1968, when the company was sold to Avery Ltd.
Luckily I came across a fantastic website curated by Thomas Allgeier.
Stanton Instruments LTD which contains a wealth of history and information on SI balances.
The B15 is an aperiodic, auto-loading, equal-arm, analytical balance capable of directly reading 0 to 10 mg. from the graticule screen, and up to 100 grams using the “Omni-weight” auto-loading attachment. It has a sensitivity of 0.1 mg.
The Stanton Instruments B15 sold for £ 150 (pounds sterling) in 1957 which is approximately equivalent to $4,333 USD in early 2021.
Restoration started with the base assembly and removing all parts attached to it. The base was stripped of all external paint before structural repairs were made, then sprayed with Rust-Oleum sandable grey filler & primer. After the surface was sanded and prepped, I used Rust-Oleum “Smoke Grey” gloss enamel for the final coating of the case. Several of the metal parts including inner rails, side door slides, and window glass holders, were painted using Rust-Oleum “Hard Hat” Light Machine Gray enamel.
Many of the balance pieces are attached to the base, so I took extra time and effort to verify dimensions and squareness of this piece.
Next was the rebuilding of the arrestment cam assembly located under the black glass base. The cam assembly has several duties including raising the arrestment arm and pan dampeners, along with operating a microswitch for the lamp, and supporting the lower optics first surface mirror. Unfortunately I didn’t get any pictures of the work done, but had a picture of the base assembly from the original documentation 20 years ago.
The next part involved lot’s of paint stripping of the rest of the case in preparation of repairing the worst of the shipping damage. Repairing the case involved lots of glue, and every clamp I owned. This happened in several incremental steps, until everything was aligned and stable.
The middle case sustained the most shipping damage and required the most time to finish. Several areas of the case require a bare wood finish such as the front sliding door guide slots, and front glass slots which required masking for each paint coat.
Next up was the “Omni-weight” auto-loading attachment, which after sitting for two decades was very stiff from dried out lubricant. After a thorough cleaning and relubrication it was operating smoothly again. The original rubber on the dampening bars was hard as a rock and required replacement.
Several of the first surface mirrors in the optical path required replacements, before I could reassemble the unit. I also decided to build a replacement LED light source, instead of reusing the original incandescent light source.
After picking up a piece of single pane glass cut to specific dimensions from our local hardware store, I was finally ready to put everything back together.
New green felt was attached to the lower front door edge, along with new grey single sided velvet ribbon between the front glass support and door to prevent external air drafts from disturbing internal components.
Several of the rider weights were lost during the initial shipping incident and needed to be replaced. I ordered some high percentage chrome / nickel stainless steel straight wire in several different diameters to fabricate the replacements from.
The circular weights were the easiest, requiring a round form of the correct diameter, forming the wire tight around it and then twisting the ends leaving some excess to trim down to their final weight. The bell shaped weights required a bending jig, and a bit more measurements to get the lengths and angles correct. The most tedious part was removing extremely small amounts of material using a diamond file to exactly match my Class S calibration weights.
It was definitely a fun project at times, but I can do without any more paint stripping for several years. The B19 balance was actually used for a research project many years ago, but not so much anymore.
The next project for these balances will be a dedicated concrete or granite weighing table to properly support and dampen vibrations.
Many thanks to Thomas Allgeier for providing documentation and answering my many questions, and my wife Leann for her support during this lengthy project.