Industrial Angle Grinder Repair

UpUp


This page details my work on repairing a 7" industrial angle grinder . I got it for $10 at an auction and it spent a while in my pile of broken tools awaiting repair. Now that I had some time to waste, and did not want to throw it away, I decided to give it a look.

It obviously has seen a long and tough life and was at some point dropped, had a handle broken and repaired by semi decent welding, and also lost a switch.

When powered up, it produced a gigantic spark and died.

I opened it up. To open it up, I had to make a slit in one of the screws that had its philips end stripped out, and remove it with a flat screwdriver.

I had a similar experience before with a 450 RPM drill . It's the carbon dust inside that shorts something brush-related. Without thinking too much, just as I did with the drill, I blew out the dust inside with compressed air. It worked.

I found a suitable power cord in my junk pile. I drilled and tapped a hole in the handle using A 1/4" drill and a 5/16"-18 NC tap, and used a screw to hold the cable.

I inserted the cable and connected it to the drill. Please note that this setup is missing the necessary power switch, so this drill will have to be run from a foot switch or some such, until I identify what it is.

Here, pictures tell us the story.


(Click on the thumbnail images to enlarge)
Thumbnail
Picked up at auction for $10
Thumbnail
Hasty repairs made at the factory
Thumbnail
Screw with stripped philips head
Thumbnail
Making a slit with a dremel tool and cutoff wheel
Thumbnail Thumbnail
Thumbnail
Screw with a slit
Thumbnail
Unscrewing
Thumbnail
Removing junk wires
Thumbnail
Blowing out carbon dust with compressed air (wear goggles)!
Thumbnail
Test bed setup
Thumbnail
The drill runs! See blue sparks!
Thumbnail
Replacement power cord, 14 gauge, tough insulation
Thumbnail
It was loose when simply inserted
Thumbnail
Drilling 1/4" hole for tapping
Thumbnail
Tapping 5/16" thread
Thumbnail
Cutting appropriate size screw. I goofed and cut it too short, had to find another screw just the right size -- so this screw you see was wasted.
Thumbnail
Now the cord is held very tightly!
Thumbnail
Screw is holding the cord
Thumbnail
Wires connected
Thumbnail
Case closed
Thumbnail
Completed repair (still needs power switch)

 Counter