magnificent anachronism---the sensitive research scama inscriber --1927

local collector/vendor kindly previewed an exotic --Sensitive Research Instrument Corporation radial inscriber used to create legend on radial analog dial insert of metrology instruments

when the corporation was formed the stated goal was production of field instruments providing 10 times greater sensitivity than competitive products

each instrument required unique dial/scale incorporating reflective needle reference mirror strip

and lettering/scribing had to be flawless--so the firm devised the SCAMA--
radial inscriber featuring jewelled platten quadrant
instrument base is finest linen phenolic
the user manual emphasizes operator skill and a substantial learning curve


collector JL is offering the unit for sale--if interested--please relay pm

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vintage draftsman instruments used---dip pens

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I found this very interesting as I have, in my little "museum" of interesting electronic, mechanical and optical curiosities, a Singer/ Sensitive Research DC millivoltmeter;




The meter dial;




I wonder how many of these SCAMA machines existed; if only one, then this dial would have been done on that machine.

The label inside the case lid is a very nice presentation; it indicates that the meter was made in 1968.




The voltmeter is ex-US Navy; it must have been in use until well into the digital era if the calibration sticker is any guide;

The picture of the exquisite meter face from the DC ammeter breaks the increments to .02 units by usage of a slant line. Was the slant line something that was done on the machine, or was it a hand add off line?

gbent said:

The picture of the exquisite meter face from the DC ammeter breaks the increments to .02 units by usage of a slant line. Was the slant line something that was done on the machine, or was it a hand add off line?

Click to expand...

Those slant lines are called transversals. They were used by various of the accurate meter manufacturers. I have several Sensitive Research meters as well as others. I used Sensitive Research meters in the pre digital age. One that was a very useful meter was called Universal Polyranger, effectively a Simpson 260 without ohms built like a lab meter. The only problem was that they used a thermocouple for AC voltages and they must have run it at the edge of safe operation. Everyone who used it eventually got a little over voltage and burned it out. I have a later model Polyranger that has the thermocouple mounted in the underside so it can be changed without opening the case.

One factoid from that time- I was light blond then with a crew cut. I used it to read mirror scales by positioning my hair to be reflected in the mirror for a light background.

Bill

Sensitive Research Instrument Corp was acquired by division of Singer Sewing Machine Co I believe in late 30's. Singer is recognized as the first global conglomerate corp and a major metrology-aerospace component manufacturer

Singer transferred ownership of Sensitive to Electrical Instrument Service Inc
in late 50's

the unit displayed here was surplussed from local naval shipyard--the US Gov and DOD are largest global user of vintage analog instruments

appears to me that the SCAMA inscriber never was placed into service--not a surprise considering the demand for perfection in every motion required in creation of scientific dial scale
low wattage lasers and cnc engravers sent this device to the historical instrument dustbin with no residual sentiment for its return

Really neat! I have several Sensitive Research instruments and some others with hand drawn scales.