# Micromill/drill upgrade completed



## hobby (Jun 10, 2011)

Hi everyone,
This is a short demo, of my upgrading my micromill/drill,

http://www.youtube.com/embed/g9vWT3A3WEw"


 I made the pulley's out of aluminum round bar stock.


I never made pulleys before, so I did a little research on the innernet, to find out the ins and outs of V-belt pulley design, my first pulley did not work properly, as I made the inner diameter to shallow, that the bottom of the v-belt would touch it and slip.

So after reading up on the subject, I realized that the inner diameter needed to be deeper so the v-belt did NOT bottom out on it, this way when a load is introduced to the driven pulley, (spindle), then the belt would be pulled tighter by the motor spinning, thereby causing the v-belt to wedge itself deeper into the pulley groove, making it tighter so NO slip could occur, under normal loading conditions.

I made a single point pulley groove cutter from a 1/4" hss, lathe cutter blank.

The motor driving circuit works real good, no need for any kind of voltage regulation, the motor runs at good speeds when the spindle is loaded, without any excessive bogging down.

All in all I am very pleased with this upgrade, to my milling machine.

Have a great day..


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