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The Flat Lap

This is part of a series on cold working equipment.  Click here to check out the beginning of the series.

The flat lap (sometimes called a flat bed grinder) is  used for grinding a flat surface on glass or on the top edge surface edge of a slumped bowl.  It's a large horizontal wheel similar in concept to a record turntable or potter's wheel.  There are two basic types -- the vibratory flat lap and the rotary flat lap.

The vibratory flat lap (also called a reciprolap or an automatic vibrating lap), uses silicon carbide or aluminum oxide grit or polishing powders to smooth the surface of the glass.  This type of machine automatically vibrates, and can be operated without constant attention. 

To use the reciprolap, the machine is first prepared with a slurry of the desired size grit.  (As with most grinding/polishing activities, the procedure starts with coarse grits and finishes with finer particles.)  Once prepared, a piece of glass is placed on the lap and the machine is turned on.  It vibrates under the glass, steadily abrading, grinding, and polishing the piece.

Although relatively little attention is required while the machine is vibrating, grinding and polishing with a reciprolap is a time consuming process.  Each step of the process takes a day or longer, with weights often being placed on top of the glass in order to accelerate the process. 

To prevent contamination, the machine must be cleaned thoroughly between grits.  Or, more frequently, a series of machines is used to complete the process, with each machine dedicated to a single grit.  The entire procedure, from rough grinding with a coarse grit to final polishing with polishing powders, can take several days and sometimes even weeks. 

Because of the expense of these machines, the reciprolap is most often used in more industrial or high volume settings that can afford a series of automated machines. 

Click here for information on the rotary flat lap, an alternative that grinds and polishes glass using an abrasive disc (usually diamond).


Copyright 2006 Brad Walker.  All rights reserved.

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Copyright 2005-2006 by M. Bradley Walker.  All rights reserved.

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