Emco Unimat 3 Milling Column rotational locking clamp

thingiverse

This versatile clamp empowers users to immobilize the Unimat 3 milling column spindle, facilitating the secure placement of a digital indicator or dial indicator within the Jacobs chuck. By harnessing the leadscrew handwheel, cross slide, and vertical fine feed, users can precisely position the tip of the indicator, enabling it to traverse surfaces and generate a set of coordinates (contour map) for seamless importation into a CAD program. The clamp's design allows for effortless printing from various filament types, with PLA being an optimal choice. The tightening screw bore accommodates standard M5 allen bolts and nuts commonly found on Unimat accessories, such as milling table clamps, which can be temporarily repurposed for this application. The two provided bolts are identical to those typically used in the column's motor assembly. The digital indicator is showcased capturing the shape of a vintage DEC VT100 computer terminal keyboard key. By systematically traversing the leadscrew travel and recording the corresponding indicator values, users can create a detailed contour map. This process involves carefully moving the milling column up 1mm between each reading, allowing for precise data collection. A generic Golden Dragon digital indicator, acquired through eBay, features a plain flat backplate instead of the anticipated fixing eye backplate. Fortunately, an existing solution (https://www.thingiverse.com/thing:1332174) addresses this issue by incorporating a Unimat tee bolt and nut that passes through the eye, enabling secure clamping within the chuck.