Regular lubrication with carefully selected lubricants is an essential factor in satisfactory functioning of the machine tool for a long time.
Before putting the machine into operation, the various oil reservoirs should be filled with oil upto the oil sight glass. The various parts should be lubricated as per the lubrication plan supplied by the manufacturer of the machine tool.
The lubricant recommended in the case of lathe, for head stock, feed box, speed gear box, gears, and general lubrication, is ‘Mobil oil DATE Heavy Medium’ of Indian Oil Company; and for grooved pulley bearing and motor bearing is ‘Mobil grease BRB 1’ of Indian Oil Company.
Lubrication of Head Stock:
Initially the oil is filled in the head stock after removing the screw cap provided on the top of the head stock. The oil level is visible on the right glass generally provided on the rear side of the lathe. Oil can be drained through a drain plug provided at the bottom.
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Usually the oil is pumped by a piston pump operated by a cam and the oil is first passed through a wire mesh filter designed to trap all impurities and then to the front bearing, and also to the various rotating head stock parts.
Changing of oil is done first after 200 hours running, then after 500 hour and later every 2000 running hours. Before filling with new oil, the head stock should be washed with kerosene and thoroughly dried (fluffy rags should not be used for this purpose).
Lubrication of Speed Box:
Speed box is lubricated by a continuous splash of oil. The speed box is generally housed in the cabinet leg, directly below the head stock and to gain access to it, the rear cover of the cabinet leg is removed. The screw plug on the speed box is removed and oil is filled in, upto the set level in oil sight glass.
The speed box pulley bearings are generally filled with grease while assembling at the work. To replenish, the pulley with grease end plates are dismantled, cleaned well and refilled with a bearing grease having a melting point greater than 140o C.
Lubrication of Feed Box:
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The lubrication in the feed box is effected by a piston pump driven by an eccentric fitted to one of the rotating shafts. Oil is pumped to a reservoir on the top of the feed box and from there oil is fed through pipes and channels which ensure oiling by capillary action through wicks.
Lubrication of Saddle and Apron:
These are lubricated from a hand pump fixed at the right hand side of the saddle. Oil is drawn from the reservoir and is pumped to various points (bed slideways, cross feed unit, apron gears). The screw plug on the top of the saddle is removed for filling oil into the reservoir. The hand pump should be operated 4 to 6 times every day before operating the saddle movement.
Worm Housing and Lead Screw End Bearing:
Worm housing is lubricated through the oil nipples under the levers of the apron, with an oil gun. The end bearing of the lead screw is wick-lubricated from an oil pump in this bearing housing. Oil is filled in every three days into this pump by removing the screw plug on the top of the end bearing.