Magnetic Base

Workholder assembled

Adjustment Handle

Plasma gun holder

DC Supply

Cutting

Finished pieces

The work holding spindle. A magnetic base will be fastened to a plate and sleeve that fits the motor output shaft. A copper slip ring provides a surface for the carbon brushes to contact and allows the workpiece to be grounded for the Plasma Cutter. Brush assembly was salvaged from an old motor that powered a Massey combine header lift.

The magnetic base has been bolted to the plate and the brush assembly placed over the copper slip ring.

A bit of fooling around here. A piece of 2" iron pipe was attached to a sleeve with 3 spokes. The knob serves as the adjustment for the size of circle that will be cut.

Gear reduction DC motor mounted to an old drill press stand. Gun holder is adjustable horizontally and vertically to allow for differing thicknesses of stock and size of circles desired.

This is a regulated and adjustable .5 to 20V DC power supply that I home-brewed several years ago. Ball bearing planetary knob allows for 2-speed adjustment of voltage. 1:1 ratio allows coarse adjustment and 6:1 ratio allows precise adjustment. Supply has a switched meter that displays either Voltage or current

Plasma torch in action.

12" O.D. X 8" I.D. rings have been cut from 1/4" steel flat plate. The switches to the right of the power supply control the motor direction of travel and On/Off. The spring was added to the circle size adjustment screw linkage to eliminate backlash.