We Make America Productive
Rewrite of Customer Service Bulletin No 568, originally dated 1-13-1966
Applies to: 41B2910 thru 41B3009
42B3606 thru 42B3708
and others with Magnetic Feed & Rapid Traverse Clutches
The subject machines have Mobil DTE-24 oil or its equivalent in the Speed Gearbox and Feed Distributing Bracket.
The oil in the Speed Gearbox should be changed to Mobil DTE-Light or its equivalent.See Page MC-9 in the maintenance manual for instructions on draining the existing oil.The Feed Distributing Bracket should be changed to Mobil Heavy-Medium or its equivalent.See Page MC-11 in the maintenance manual for instructions on draining the existing oil.
The present (original) oil (Mobil DTE-24) in the Speed Gearbox - which also supplies the Feed Change Gear Box - has an Extreme Pressure (EP) additive.This has an excessive shear effect, which increases the Feed and Rapid Traverse clutch idle torque.Any oil with an EP additive causes excessive drag in the clutch plates and greatly adds to heat build-up from friction.In addition, the EP additive will coat the clutch plates and cause them to be incapable of delivering full driving torque.
To remove all traces of DTE-24 from the Speed Gearbox, flush it thoroughly with a suitable solvent such as Varsol or Stoddard solvent - which are non-toxic and non-flammable.
It is not absolutely necessary to flush the Feed Distributing Bracket before changing to the Heavy-Medium oil.This change is to insure rapid disengagement of the sliding clutch gears.