About KS7470 oil and KS7471 grease
Part of
the UI-8 pages
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About KS7470 oil and KS7471 grease
Part of
the UI-8 pages
|
The teletype manual states that the Teletype should be lubricated with KS7470 oil and KS7471 grease. These are old Western Electric part numbers, and they may be long gone, but the Materials Safety Data Sheet (MSDS) and product specifications are still around and available from numerous web sites, and we can reconstruct enough from these to find modern equivalents.
Aside: KS numbers were ubiquitous in the days when Western Electric and the Bell System monopolized the telephone industry. Some have said that KS stands for Kearny Standard, indicating that the specification for the tool, component or product was developed at Western Electric's Kearny Works in Kearny, New Jersey. However, the Kearney works was opened in 1926 and KS numbers have been found in documents from as early as 1924. It is possible that KS numbers date back to the era when Western Electric had a warehouse on Kinze Street in Chicago where third-party products were stored. Perhaps KS stands for Kinze Supply.
From:
www.chemcas.com/msds111/cas/151/94461541.asp
(archived copy)
This is the MSDS for KS7470 prepared by American Oil and Supply Co.
of Newark NJ, the original source for this oil. The specifications given
are incidental to documenting safe handling, but between fire safety and
physical characteristics, several are valuable:
From:
www.wbparts.com/rfq/9150-00-448-5009.html
These are the specifications for NATO Stock Number (NSN) "9150-00-488-5009
Lubricating Oil, Instrument" which includes KS7470 and several other oils.
Another way to pursue this is through the MIL spec. The NSN ties to Joe Duszyński has pursued this avenue and found that The Technician's Handbook, Module 19 of the Navy Electricity and Electronics Training Series NAVEDTRA 14191 lists (in table 1-40) KS 7470 oil as having the "new military specification" MIL-L-17672. Numerous web sites list this as "lubricating oil: hydraulic and light turbine oil (noncorrosive)."
First, note that the American Oil and Supply Company is still around, at http://americanoil1895.com/, currently located in Shrewsbury, NJ. KS7470 is not in the product listings on their current web site, but a Teletype enthusiast has recently contacted the company and learned that they still have the original formula on file and would be willing to investigate producing a small batch of the real thing.
Comparing the specs above with the specs for currently available oils gives an extremely close match to a number of oils that are all highly refined white mineral oils:
In contrast,
Working from the MIL spec number MIL-L-17672, numerous products are on the market that claim to conform with this; these oils also generally claim to conform to DIN 51506, DIN 51515, US Steel 120, Mitsubishi Heavy Industries E00-87182 and other industrial standards. Joe Duszyński concluded that this is ISO Viscosity Grade 46 hydraulic oil, and his comment is that it acts about the same as authentic KS 7470 but "just doesn't have the smell."
From: an MSDS no longer available on the web
This was the MSDS for KS7471 prepared by General Bearing Cleaning Co.
Trenton NJ, a division of Ceram Co. of Morrisville PA.,
the original source for this grease.
The most important piece of information in this MSDS is the following:
From:
cuttinglubeandhydraulicoil.tpub.com/2/00-077-3545.htm
These are the specifications for NATO Stock Number (NSN) "9150-00-077-3545
Grease, General Purpose" which includes just KS7471 and nothing else.
Unfortunately, since there was just one supplier, no useful specification is given, simply that the product comes in 1 pound units and must be marked KS7471.
First, note that the General Bearing Cleaning Co. appears to be long gone, and its parent company, Ceram Co., has been swallowed by Lucidon. www.lucideon.com. Lucidon's U.S. addresses no longer include any locations near those listed in the old KS7471 MSDS.
From:
cuttinglubeandhydraulicoil.tpub.com/8/00-944-8953.htm
Nato Supply Number "9150-00-944-8953 Grease, Aircraft,"
is documented as meeting the Mil-G-81322 specification.
There are numerous modern suppliers for this, including:
Searching the web, both of these were available in many different packages (cans, cartridges, buckets) through vendors such as eBay and Amazon.
One issue remains unresolved here. The Teletype manual recommends mixing KS7470 oil with KS7471 grease for some of the lubrication points in the Teletype. This mixture is not problematic with natural greases and oils, but the substitutes for KS7470 oil identified above are all highly refined light mineral oils, whereas the substitutes for KS7471 grease given here are both synthetic hydrocarbon greases.
There are warnings in the AeroShell Book, page 142, about potential problems resulting from mixing greases with different kinds of thickening agents. Lithium grease (soap based) should not be mixed with microgel or clay thickened greases (including the synthetic substitutes identified here). It is unclear how these warnings apply to the kind of mixtures recommended in the Teletype manual, since the highly refined oils involved contain no thickening agents and few if any additives, but it would be prudent to run some tests before committing to the large-scale use of such mixtures.
A second issue matters, compatability with the ABS shell of the Teletype and the plastic internal components. The contact blocks inside the ASR-33 Teletype appear to be made of acrylic plastic, and there are plastic and synthetic rubber (neoprene?) parts in the drive train. The highly refined light mineral oils recommended here are unlikely to pose a greater threat to these plastic parts than the original KS7470 oil.
In the case of the grease, see the AeroShell Book, page 141, for a general discussion of the plastic compatibility problem. In general, synthetic oils and greases based on esters are a threat to ABS and many other plastics, while those based on synthetic hydrocarbons are not as bad. The greases recommended here are hydrocarbon based, so should not pose a greater threat than the natural hydrocarbons in KS7471. Nonetheless, follow the Teletype manual's advice about protecting the plastic parts from the oil.