Cincinnati End Mill No. 6 - lube oil help

May 22, 2023
Hello Everyone,
We are resurrecting a Cincinnati Machine End Mill No. 6. We believe it was built late 1960's.

We are having an issue shifting gears and we are actively looking for the correct oil to replace the CMMCo. No. P-38 oil.
According to the tech manual - the P-38 will be used for Column gears, bearings, hydraulic pump, etc. (See section 17 in the attachment).

We rebuilt the oil pump so we are getting flow to all areas of the machine.
When we start the end mill - our oil pressure is ~200 as it warms up = we drop to around ~150.
To shift gears the tech manual states we need to be around ~200.

The prior oil was contaminated and removed. The current oil is Mobil DTE 24. We believe the oil is not correct.
Possible Mobile Oil is Mobile DTE light if we want to stay in the 15 - 20W class or Mobile DTE Medium Heavy if we want to stay in the 75W class.
We also have Lubriplate HO-1 which is 20W.

Required viscosity 145-160 @ 100F or 40C per the P-38 spec and is ISO 32.
To convert Mobile Kinematic cSt to SUS - formula cSt XXX x 4.63 = SUS XXX
Mobile DTE Light = Kinematic (cSt) 31 x 4.63 = SUS 143.53
Mobile DTE Medium Heavy = (cSt) 65.1 x 4.63 = SUS 301.43
Lubriplate = 196.2 @ 100F

Attached are all the supporting documents.
With the age of the machine - we are attempting to make a best replacement.
Mobile DTE Light viscosity 143.53 ISO 32 or Lubriplate viscosity 196.2 at SAE-20 (due to the age of the end mill).

Any help will be appreciated!
Mark K


  • End Mill.jpg
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  • Viscosity Chart ISO 32.jpg
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  • Mobil DTE PDS.jpg
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  • Lubriplate HO-1 oil Datasheet.jpg
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Hello Everyone,
Attached is the Cincinnati Machine Lubrication Manual - which gives cross references!
Happy hunting!
Mark K


  • Cincinnati Machine Lubrication Cross Reference.jpg
    Cincinnati Machine Lubrication Cross Reference.jpg
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