I get e-mails from drill plans purchasers wanting to know where to get the electric motors to run the Mini Drill and Micro Drill projects. It would seem that some of the sources Dad mentioned in the plans are no longer available. Those of you who found a motor, can you share with us where you got it? (if they are still available)
I went to Mendelson's in Dayton (one of Dad's favorite places to search for various items) to look for any surplus they might have, and did not find anything matching Dad's specs, as most of the motors they had there are AC or stepper motors.
For Micro-Drill, Dad calls for: 12 volt DC, 1-1/4" long x 7/8" diameter with a 1/8" diameter shaft. If you can't keep the motor from turning by pressing on the shaft with your index finger and thumb at 6 volts, then it should have enough torque.
For Mini-Drill, Dad calls for: 24-28 volts DC, min 3000 RPM, permanent magnet, ball bearings, 2-1/4" to 2-1/2" diameter and a 1/4" or 5/16" diameter shaft.
Again, if anyone knows of a source for these motors that match these specs, or if you used a motor with different specifications with good results, please reply here, or send me an e-mail to firstname.lastname@example.org.
A builder responds:
"I found a good motor for the mini drill from Zoro on the internet. You can power it with a lap-top type 24v 10 amp supply, but you will need to create a starting device. The resistance before starting is 1.2 Ohms which will draw a 20 Amp surge when starting, looking like a short to the power supply. One way is to put the switch on the ac line side so the power supply and the motor ramp up together. Better to add a 2-3 Ohm 5W resistor shorted out with a relay after a second or two.
Or you can get a big power supply and put it in a box, resulting in something the size of a bread box. Not cool.
The motor I got from Zoro is their # G1958126. 24 V, 6 Amp, which fits nicely."