My neighbor kicked two Razor E200 electric scooters to the curb some months back, so of course I took them home for salvage- he tends to throw away some good stuff. Turns out to be a smart move because the motor on my 1950 Duro drill press died, and this gave me the chance to add variable speed and reverse to my machine, a very easy modification that most anyone can do.
Step 1: The Goodies
After determining the scooters were beyond economical repair, I removed the electrical and drive systems from both. I now have a heavy duty pulse width modulated D.C. speed control, on/ off switch, thermal circuit breaker, and a nice 200 watt 24 volt d.c. motor set from each. Only one motor was of interest for this build, so the rest will be shelved for some future project.
Step 2: Fit It Up
The motor shaft is 8mm (.315) diameter, and the standard motor pulley arbor is 1/2” (12.7mm) diameter, so I turned an adapter on the lathe to join them together. Mounting was rather straightforward, using wood scraps to position the motor as needed for a straight inline drive to the main spindle lower pulley. Since the brushed motor is variable speed, I did not need to accommodate the upper grooves to obtain speed change. A simple linear power supply was fashioned from a salvaged transformer, rectifier, and filter capacitor, with no regulation needed.
Step 3: Power It Up
At top R.P.M. the voltage output is a very agreeable number for a 24 volt d.c. motor, and I like the option of simply swapping supply leads to reverse rotation since I have a bunch of left- handed drill bits I acquired real cheap, as not being the usual right- hand type. Final customization of the stand was to add a front panel on/ off switch controlling a dedicated receptacle outlet.
Step 4: Parting Thoughts
The motor, due to it's design, is not rated for continuous use, but if required I can add a cooling fan for prolonged operation, however most of my needs are only for a few simple, quick, and accurate holes in my projects. Like many drill press users, I have found my “sweet spot” for the most commonly used bit sizes, which are fairly small, thus I tend to use the top end of output rotation, but for the rare instance when a large diameter bit is called for, I simply clap on my H.F. variable A.C. speed control and throttle back to the R.P.M.'s that are most effective. In closing, the only cost was for the pulley, about $4.00, not a bad exchange for a better tool.