Re: Re: Scratch-built CNC mill

CG wrote:

> Why don't we just use glass scales??

The question really should be - why *do* people use glass scales. Close
contacts with a company which made precision measuring products taught
me that the material which machine scales are made from should match
either that of the machine itself or the material being processed. In
this way, its not necessary to take any account of changes in
temperature. That is - a steel scale on a steel machine will remain
proportional at all temperatures. If you are working hard on a large
metal part it gets hot and will consequently expand, so, logically, if
you are relying on a scale which does not expand as much or is in a
position where it is not affected by the heat of the work, the work will
finish up undersize when it cools down. opinions anyone??

Best wishes

Ian

--

Ian W. Wright LBHI
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