Steps to get a Rotozip with a broken shaft lock back to a useable state.
created: 2013-08-31 | topic: electronics | tag: repair,teardown | author: Jason Lenz
I have a Rotozip that I used quite often that unfortunately broke. The issue was with the button that is used to lock the shaft so that tools can be changed. While changing a particularly stubborn tool, the internals of the button suddenly gave way and remained jammed. I couldn’t change the tool or use the Rotozip anymore. It sat collecting dust on the shelf for about six months because I assumed it was completely broken and because I didn’t have the heart to throw it in the trash. I eventually decided to take the plunge and pull it apart to see if I could figure out the issue.
The first order of business was to remove the quick release handle and then take out the seven screws highlighted by the red arrows below. You will need a size T20 torx bit to remove these screws.
Next you’ll need to slice through the labels on the sides of the Rotozip. The manufacturer cleverly taped these across the separating seam so that they could tell if anyone opened it up. Since mine is out of warranty anyway the easiest solution was to cut through the labels right along the seam using a razor blade or utility knife (see the yellow line below). You’ll need to cut through both labels on each side of the Rotozip.
At this point I was able to pull the Rotozip open and observe what was going on inside. The first observation was that the Rotozip was filled with drywall and wood dust which I blew out with an air compressor hose before reassembling. You can see the bent stop pin in the images below. The metal bushing essentially tore out of the plastic housing holding it in place and jammed the shaft. You can see the scratches on the metal shaft where the pin dragged when I was trying to open up the collet.
I pulled the wedged pin completely out of the housing since it was useless at this stage. Assuming the motor was still running fine a metal rod could be inserted through the opening where the old pin was whenever I needed to lock the shaft to change a bit.
I also was able to pull the motor most of the way out of the housing so that I could completely blow out the various nooks and crevices in the Rotozip. While doing this I also noticed a wire that was basically worn through because it was improperly installed in the factory and had been rubbing constantly against a motor element.
I had no desire to leave this fire hazard as is, so I pulled the quick connects off where the wires connected to the motor and put some heat shrink tubing over the wire (it just fit over the connector). I also ended up putting heat shrink over the second wire. You can see the second wire was pinched in the photo below.
Below is a picture of the Rotozip just prior to closing it back up. You can see the pieces of the old locking pin setting next to the housing.
And here’s the assembled Rotozip with the opening visible. It turns out that an 11/64ths drill bit is the largest diameter that will fit into the shaft opening. I have an old drill bit that I’ll just plan on keeping with the Rotozip to use for changing bits. The old stuck zip bit came out no problem, and the Rotozip started up like a charm. Back in business!