Turning Two Broken Drills into One Working Drill

 

We had a Worx "switchdriver" that had a feature of switching quickly between two different bits by rotating the front half. This was convenient for putting a drillbit in one half and a screwdriver bit in the other, and switching back and forth quickly. Here's an Amazon Affiliate link to that drill: https://amzn.to/330y3mh

Picture from Amazon.com

Unfortunately, this drill stopped working. Griffin looked inside, but didn't want to completely take it apart until his dad figured out if it could be replaced under any type of warranty. So he put it on a shelf for about a year. When he took another look at it recently, he figured out that motor was fine but the speed controller failed.

Today, Griffin tried to use another cordless drill to help replace the handle on a garden rake. But when he started drilling, smoke came out of the motor of the cordless drill. He figured out that the motor of that Craftsman drill had burned out. 

So now Griffin had two broken drills- one with a good motor and bad controller, and another one with a good controller and bad motor. He wondered if he could combine the good parts from each to make one working drill.

At first glance, the motors looked identical. They were exactly the same size, and the gear on the motor shaft looked like it was the same size too.

 Griffin tried to fit the good motor into the other drill. First, he swapped the plastic coverplate that needed to lock onto the gearbox. 

The gearboxes did look different- one had five gears that surrounded the gear on the motor shaft, and the other had three. But that shouldn't matter if the motor shaft gear of each motor was identical. He tried and tried to get the motor to fit, but something was wrong.

Mom took a look and noticed that one gear had 11 teeth and the other had 12. Oh no! The only way to make this work would be to swap the gears from the motor shafts. Unfortunately, these gears weren't designed to come off. How frustrating!

Griffin used pliers, screwdrivers, hammers, crowbars, and a vise to pry the gear off the good motor. He got it off without damaging the motor. Next, he had to get the gear he needed off the bad motor. Unfortunately, the entire shaft came out of the motor with the gear. He was able to hammer the shaft out of the gear using a nailset. 

He transferred the correct gear to the good motor shaft, and then reattached the plastic coverplate. Success! The gears meshed together correctly and the plastic coverplate locked the gearbox on. 

Then he soldered the wires to the motor and screwed the housing back on. Success! The drill works great now. It sounds slightly rougher than it used to and the light does not work