Variable Speed AC Rotary Tool

Variable Speed AC Rotary Tool

Replacing the OEM Dremel

This is a shiny new No-Name Variable Speed AC Rotary Tool.

The unit was an impulse purchase based on a sale that I missed at Princess Auto just before Xmas of 2004.

I paid $35 CDN at an el' cheapo tool liquidator depot.

Overall I'm quite impressed with what $35 CDN gets in a tool like this.

For what I'll have this unit doing it's important that it has decent bearings, and these are certainly sturdier then the dremel OEM.

The brushes, are just that brushes, and how well they last has yet to be determined.

This is the front bearing, and it's identical to the one to the rear of the motor.

The motor shaft is a continuous piece of steel that is threaded to accommodate the collet, and seems quite have no play.

Behind the bearing is a molded fan that is driven directly as the motor turns, clearing the need to add external active cooling.

This is a minimalist AC Speed controller, but seems to be more than adequate.

I assume that it is some sort of SCR fired sine wave chopping type circuit.

The only flaw is that the motor won't spin if it is turned ON at the lowest speed setting, but starts right-up when the control is advanced, and will spin at the lowest speed, once running.

Now that I have a spindle speed control, I tried various speeds to see if I could get an even better finish on the EPS Foam patterns that I've been cutting.

The reduction in noise has been great, the dial is set to about 1/4 past the No.2 speed indicator.

To give this some more meaningful value I used an old mechanical Tach (the type you time with a watch) and over 3 (three) test runs consistently came-up with approx 2100RPM for a 0.030" cutter and approx 1900RPM for a 0.050" cutter both at a 10 Inch Per Minute Feed.

The Rotary tool, fits in perfectly where the dremel OEM had been.

This is a pattern milled 0.100" into a 1/4" mahogany flooring panel.

Definitely tougher than pine, and to be avoided as it still took 3 passes at 40, 40 & 20 thou.

Also I toasted a cutting bit in the process.

This final image was what I had in mind when I first picked-up the AC rotary tool.

This is a crude form of Marquetry, where an image is formed with contrasting woods or grain patterns.

The light grain panel had the paw print cut a full radius off-set smaller than the insert pieces which were cut a full cutter radius off-set larger.

The above tool is head and shoulders above the dremel OEM, but largely due to the variable speed control, and has run over 40hrs since the new year with only the initial oiling procedure as outlined on the previous page. Until either the "NexMill-15" is completed or I build a DC speed control for the dremel OEM, this unit will stay put.

I have a 30" by 72" custom counter-top to make that will feature similar and more complex patterns, but either I'll have to employ the 3/4HP Roto-Rebel knock-off or find an even thinner (and softer) veneer to work with.

Support theworkshop.ca

Back to Machining