One of the things that a lot of people forget to do is maintain and clean their tools.
Have you ever gone to your grinder and found that the set screw wont move and the head is stuck solid on the drive shaft? If you haven't, you will and you're not alone, we have done the same thing.
Well, don't panic and think you're gonna have to go buy a new grinder. All you're gonna need are a couple of tools that I'm sure you have around except maybe one. First you're going to need a drill with a bit and make sure that bit will fill the hole where the set screw is on the grinder head. A cheap gear puller which is probably the item you don't have just laying around and a wrench to fit the gear puller.
Gear pullers come in all shapes, sizes and cost. Don't go out and spend a fortune! The gear puller we use we found at Autozone and I think we only paid twelve dollars.
First thing you are going to need to do is drill out that set screw. Remember you are drilling metal so use oil to keep things cool and keep the drill going a little slower, not on a high speed. Once the set screw has been drilled out attach the gear puller.
The two or sometimes three outside arms of the gear puller fit under the grinding bit. Slowly hand tighten the center screw on the gear puller until it is snug. Now you can use that wrench to slowly tighten the center screw. Go slowly and as you tighten the screw you will see the grinding head slide up the motor shaft. After a few turn the grinding head will come right off.
If it is easier you can remove the grid system on top of the grinder before you do anything, that will give you a little more room.
Now just remember when you are putting on the new grinding head put a little Anti-Seize on the set screw. By doing this it will help eliminate this situation in the future and its probably a good idea that when you are done using the grinder for the day to take the grinding head off. Just a little ounce of maintenance and prevention will make your tools last a long time and eliminate a real headache.