I should start this by saying I use angle grinders a lot. They're amazingly useful for shaping steel and wood, finishing edges, polishing pieces, removing skin, and flinging pieces of metal at your friends. I've owned several, burned a couple out from years of use, and normally keep two on my bench all the time with different abrasives on them because I use them so much. Polishing can be a very time consuming and somewhat costly endeavor, so I'm always trying to improve how I do it.
I picked up a new Norton abrasive wheel with the hope that it would speed my polishing along. It's essentially a hard rubber backing plate which supports a sandpaper disk that screws to your angle grinder with a special flat nut with two holes in the face of it. I followed the instructions, mounting it on my trusting and innocent angle grinder, and naively flipped the switch. The angle grinder immediately locked up, and screwed the nifty new wheel onto the spindle so hard that I couldn't get it to budge with a vice and a commercial tool for loosening such beasties. My efforts bent the tool. Ever try to loosen a nut and have the handle of the wrench bend instead? That doesn't ever happen, you say. But yeah, it was like that.
I had some hope that I could disengage the lock by disassembling the grinder a little. A few loosened screws later and my fancy angle grinder had transformed into a useless fist full of grease, gears and wires, with a tenacious and equally useless abrasive disk still firmly attached to its remnants. So um, that was fun. The little puritan in my murky gene pool assumed all this was my fault- some direction I didn't follow properly, or something that was wrong with my grinder to begin with, so I went off to Home Depot to buy another angle grinder, and yet another one of these nifty Norton abrasive wheel sets. They looked so nice! They said they last 10x longer than flap wheels! (Even though the only flap wheels my Home Depot are all made by the same company, so maybe they're just saying their own flap wheels suck!)
So, new grinder, new wheel, what could go wrong? After taking that useless spark guard off the new grinder I again followed the instructions for the hopeful Norton abrasive wheel. I plugged it in, and flipped the switch. Can you guess what happened? Really, try. Did you guess the same exact thing? I had a brand new sanding wheel seized hopelessly to my brand new angle grinder. Yeah, that's what happened.
So most angle grinders come with a nifty little wrench thingie. It's a flat plate with two pins sticking out the side that slide into the faces of the special nuts that hold sandpaper wheels on. You can then get the torque you need to loosen even the most stubborn wheel that your buddy over tightened onto your grinder. The one I had came with pins that were about a quarter of an inch long, giving this wayward and insanely stuck wheel the leverage it needed to bend the quarter inch steel bar/wrench thing into a taco. I'd like to think it was just my massive strength, but really it was just poor design. I spent part of a meeting today at work coming up with an improved design, and built one out of the handle of a similar tool and some parts of a nail for the studs. It mostly needed a thicker handle and shorter studs. The new tool design worked great, and let me unjam the tragically flawed Norton abrasive wheel on my new grinder. It felt good to engineer my way out of a situation created by poor engineering. Seriously if you can't make a sandpaper wheel that doesn't make a grinder try to implode or a wrench that regularly bends itself into the shape of Mexican foods you shouldn't be a mechanical engineer. If a guy like me without all the strength of materials classes you had to take can make a better tool from crap he has laying around his shop in 5 minutes, you officially suck.
Anyway, I still had one angle grinder left in pieces. If you have a grinder like the one above, they're great grinders, but be careful not to just go unscrewing it. I did, and the gears come apart in a greasy mess, and motor comes right the heck out of the case, leaving the bushings behind. They're spring loaded so they make good contact all the time, but it makes disassembling it one way trap. You have to take the whole thing apart more so you can access the bushings, holding them away from the motor so you can slide it back into the case. I did all that, and got the gears to mesh back together properly. It now makes a slight scent of ozone, but otherwise it's good as new. It's as if my grinders, and even the new addition to my grinder family had never met these awful Norton abrasive sets, and I feel like I've done some brain surgery.
There are a couple down sides to this whole tale. Because of my limited shop time due to having a job, a family, and this project, this whole saga took a few days. I reverted to some more aggressive flap sanding wheels to polish the forge scale off my cuisse. One little part of the cuisse was getting very hot very fast, which is a bad sign. Then light started shining through it; an even worse sign. This cuisse is made of tempered 410, which can't really be welded with my oxy-acetylene rig. It makes the steel take on the texture of a sponge. I tried it anyway, with some nice 4130 rod, and the hole just got bigger and uglier. So I'm stuck with either making a whole new cuisse, or finding someone who can fill this hole. The guys at the welding shop I go to didn't even have any rod for any welding rig that could do it in their catalog, so I'm not overly hopeful. I wanted to enter these legs in a competition this Saturday, but it's unlikely that they'll get done in time. So now I have three happy angle grinders, a distrust of Norton abrasives, a tool that can exorcise their demonic wheels, and a big hole in my armour.