View Full Version : magnetic chuck oil

Alistair Hosie
05-04-2006, 01:43 PM
I have a small magnetic chuck and underneath is a large screw which says oil under it inside their is a smallish chamber for oil the only thing I figure worth oiling is the lever .Is this indeed for the lever and how much oil goes in there ?Alistair

05-04-2006, 03:04 PM
Niell Tools User's Handbook says the following in regard to 'Eclipse' magnetic chucks:-

"Lubrication is necessary for the continuing efficiency of Eclipse permanent magnet chucks, in particularfor the sliding of the moving magnet system on the base and for the link mechanism. The moving parts of a rectangular chuck operate in a sealed oil-bath, conserving the oil so that re-lubrication may not be required for a very long time.

Oil seals may not remain perfect for ever, and in time oil may be lost.

Any unusual stiffening in movement of the control handle should be regarded as a danger signal that lubrication may be required, and in any case needs investigating. the control handle should never be forced round against stiffness, doing so can lead to breakages which could otherwise be avoided.

The Company recommend attention to the lubrication of rectangular chucks at least once yearly, and of circular chucks whenever the machines on which they are mounted are lubricated.

If the oil-bath has been allowed to become dry, it may be desirable to wash out the chuck, using paraffin (kerosene) or a similar cleansing medium, before refilling with oil.

Any good quality gear oil such as SAE.140 is suitable for a Magnetic chuck, but the specification of the oil used in Eclipse chucks is shown below:

Specific gravity at 60 degrees F (15.6 degrees C) 0.924
Open flash point 525 degrees F (273 degrees C)
Redwood viscosity No.1
at 70 degrees F (21 degrees C) 10,000 secs
100 degrees F (37.7 degrees C) 2,700 secs
140 degrees F (60 degrees C) 720 secs
200 degrees F (93 degrees C) 176 secs
Kinematic viscosity
100 degrees F (37.7 degrees C) 693 centistokes
210 degrees F (99 degrees C) 34.7 centistokes"

I hope this is the information that you require. By the way, NEVER dismantle a permanent magnet chuck, it will lose its magnetism and can only be re-magnetised by the manufacturer.


Alistair Hosie
05-04-2006, 05:40 PM
thanks Malc