Repair Manual for Swiss-made BesTest and TesaTast Indicators
My father taught me how to repair indicators. My very first attempt was the Starrett Last Word model 711F. Maybe it was because he had a box full of them on the shelf. Maybe he just wanted me to have experience repairing one of the worst indicators available at that time. He may have figured that, after I mastered the Last Word, the rest would seem like a breeze. I found out that most spare parts on the Starrett had to be customized to fit and to function. I had to scrape rust off the steel bodies. I had to glue and file, demagnetize and bend and pinch… it took me four hours to finish my first repair. My father could finish one in 15 minutes.
“There may be many ways to repair an indicator, but there are no shortcuts,” he said.
Imagine my relief when he showed me the Swiss indicators: Compac, TesaTast and Interapid. There was no comparison. The workmanship struck awe. The parts, beautifully engineered, looked and fit as if I were handling a fine watch.
I was fortunate to have had my father as a teacher. He had learned the skill through a rigorous apprenticeship and at the manufacturer’s factories in Switzerland. Meticulously, he taught me everything he knew. Over the years, we experienced the comings and goings of model changes, the introduction of new technologies, and the resulting repair challenges.
Having repaired upwards of 35,000 test indicators since, and having considered my retirement years just around the corner, I thought it would be wasteful if all that I had learned along the way were lost.
Today, it gives me great pleasure to pass on these instructions for the repair of some of the finest test indicators ever manufactured.
Table of Contents
Can it be fixed?
We shall begin by examining the BesTest or TesaTast indicator to see if it is worth repairing.
The most common reasons why these indicators come in for repair:
There are no parts remaining for old BesTest models which end in –1 or –2, or have no suffix at all. These were discontinued in the 1960’s. If you begin a repair on an old model and notice damaged parts, you will be best off to abandon the project right away.
Although all parts are available for current BesTest models ending in –3 and –5, it may not be cost effective to replace more than a few. Plus, it may not be worth your time and effort. It is very frustrating to have spent an hour’s worth of time to realize that this is not going to work.
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Change is inevitable and since the publication of this repair manual, the manufacturer has introduced three modifications to take note of:
1. The dials are now made of plastic but, most significantly, they no longer have the model number printed on them. This will cause problems down the road when we have to replace old dials with new ones. Unless we mark the model number either on the dial or another conspicuous part of the indicators, the customer will not know which model they have and which one they might want to order when time comes to replace it.
2. The indicator model number is etched on the cover plate of the new test indicator, above the serial number.
3. A new peek-hole is present in the movement allowing us to see the meshing of the rack lever with the crown gear teeth. The jewels are no longer bright red synthetic rubies, but are now a lighter, more rosy color.
I am grateful for having a number of errors brought to my attention by astute readers. Among these:
page 76: TESA 017203 should have the following B&S number: 99-7030-19 (formerly 99-988-30)
page 80: TESA 023012 should have the following B&S number: 99-7032-200