By Bruce Pease
The small, import milling machines may be good values; however, they invariably have metric lead screws for both table and head travel. The handwheel markings may be “close” to .001″, but the advancement per one complete turn of the screw does not result in the convenient .050”, .100”, or .200” increments of a conventional imperial threaded screw.
This can be extremely frustrating and time consuming to work with, not to mention the increased probability of error when multiple turns are required for positioning. A reasonable corrective action is to install a digital readout.
There are some very nice products that install a sensor and then digitally show the XY or XYZ location in a central display. However, perhaps the most cost effective, if not quite so convenient, solution is a variation of the linear caliper with digital readout. This is an effective fix for the shorter travels found on these mills.
The picture shows an installation of an 8″ scale on the cross travel (Y-axis) of a mill. The available product readouts include types suitable for vertical as well as horizontal travels. Sources for these scales include: LittleMachineShop.com and Shars Tool.