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Lapping Machines

GMT Lapping Machines for high degree of flatness and surface finish

GMT lapping machines

Flat Lapping Machines

Achieve positive sealing by obtaining high degree of flatness and surface finish

GMT lapping machines

GMT started manufacturing lapping & polishing machine in 1971. It was built for in-house use and until then hand lapping process was used for finishing surface plates. Critical parts for our workholding devices required a finishing and buffing machine. There was demand in the market for valve lapping and lapping plates. Since GMT had a captive ferrous foundry, castings for lap plate and lapping machine were easier to source.

Since then GMT has become one of India's largest lapping machine manufacturers and suppliers with over 350 installations throughout India mainly to the valve and pump industry. When a buyer in Japan wanted a super finishing machine for lapping large granite plates, GMT designed and supplied a 3000mm dia flat lapping machine.

Pump manufacturers, electronic industries, valve manufacturers, etc., have found a sure way of obtaining positive sealing.

Advantages of lapping

Some reasons why lapping machines help to transform a costly, rarely used, hand operation to a fine accuracy economical process:-

A partial list of the materials that lend themselves to lapping :


300mm and 400mm dia lapping machines are bench models and are robust. The lap plate and conditioning rings are made from special, close-grained, cast iron. The lap plate is supported on a preloaded taper roller bearing for maximum stability.

These sizes are constructed on a solid fabricated structure and heavily ribbed. Special attention has been given to the design of the main spindle bearings, giving great axial load capacity, maximum stability, long life and smooth performance even under heavy eccentric loading. Lap plates are manufactured from close-grained alloy cast iron, stress relieved after pre-machining and finally finish-machined and lapped in position.

Sizes 1500, 1800 and 2100 mm dia machines are massive with heavily ribbed fabricated bases. Large heavy duty roller bearings have been provided to take care of eccentric and other radial loads.

The drive is taken from the main motor through 'V' belts through a fluid coupling to ensure smooth working. The drive to the lap plate is through a heat-treated pinion and a high tensile spheroidal cast internal gear. Variable speed drive for lap plate, reverse mechanism for conditioning ring is supplied as standard. Water cooling for the lap plate is optional.

With GMT Monochromatic Lamp one can measure flatness within 0.6 microns quickly and easily. These attractive and self contained units use sodium lamp to produce a brilliant glare free light of known wave length. Contrasting light and dark bands are readily observed on most reflective or semi-reflective surfaces. Used with GMT optical flats, they measure surface flatness within 0.3µ on parts upto 75mm dia. mono_chromatic_lamp

GMT optical flats are made from clear fused quartz. Flats made of quartz are superior due to their very low thermal expansion and their greater resistance to abrasion. GMT optical flats are available in 50, 75, 100 and 150mm dia sizes.

In order to obtain utmost reflectivity from a lapped surface for light band interpretation, it is generally required to hand polish sample parts briefly after work has been lapped. GMT polishing stands are made to effectively handle a fine grade polishing paper;holding it absolutely tight to prevent rounding the edges of the work, yet permitting easy access to a new section of paper when desired. The stand is equipped to take a standard role of polishing paper.