I was playing with my new angle grinder. It’ll turn on for about 20 seconds and then shut off with a burning smell, even when I’m just letting it spin in the air. Normal or no? If it is defective would it be ethical to return it to the store for credit rather than an exchange since the initial job I bought it for is done? I can see maybe needing one some time in the future but nothing specific.
Was it doing this before you did your initial job? What was that job?
But, assuming you didn’t misuse or damage it, it’s clearly faulty and yes you can return it. Whether the store offers you a replacement or credit is up to them, there’s probably some room for negotiation there.
Yes, faulty, certainly return it. But an angle grinder is a good tool to have around just in case.
can you tell us specifically what grinder you have? many power tools have series-universal motors, and the normal electric arcing between the brushes and the commutator can produce an odor, which is usually ozone.
It may just me some machine oil burning off new parts.
describe smell.
the brushes will wear and spark some until they get seated. this could cause some odor.
The odor smells more like hot brushes as opposed to ozone.
It took a while but I managed to cut the pipes I needed to take out doing 20 second passes. There’s no model number, but it’s a Milwaukee 4.5" 11 amp. It does seem like a nice thing to have around since it can cut metal without all the vibrations of a Sawzall.
First off, how long has it been since you purchased it? 
Most places have a ‘return policy’, limiting the length of time that you can return such items. 
FWIW, it doesn’t sound like you abused it. How much of the grinding wheel is gone? If it’s a signifigant amount, the store might try and argue that it’s had too much use. (Put a new grinding wheel on it, before you try and return it. ;))
I vote, return it to the place of purchase.
IMHO, you shouldn’t have any problem getting the store to exchange it for another grinder, of the same model.
Especially, if it was recently purchased. YMMV
I bought it last week. I tried out the original grinding wheel, but it created a lot of sparks without doing much so I bought a cutting wheel and used that. The original has obviously been used but not by much.
I vote for “take it back and ask for a replacement”.
An angle grinder should definitely not shut down after 20 seconds of operation, nor give off a burning smell when not grinding. (It’s possible this is due to some sort of thermal fuse, that resets itself once it cools.)
Milwaukee tools are a higher-end brand with a very good reputation. I think the current quality may not be quite what it was 10+ years ago, but still pretty good. The store should offer you a replacement, and they will probably be able to get a refund by sending the defective tool back to Milwaukee.
Take it back. I had a cheap import grinder that lasted about 20 minutes before it burned out. The smoke in that case was burning insulation on the motor windings. I got a Makita after that and it’s been solid for 15 years now.
Could you flesh that out a bit? What does one do with an angle grinder? Would it be like pumping my Dremel full of steroids? Any reason to go with an electric over a pneumatic (I have a compressor and portable air tank)? And what about a bench grinder? I recently inherited one and am still a bit fuzzy on what role it will play in my burgeoning shop.
Generally, it can be used for smoothing, polishing or cutting metal. With the proper blade, it can also be used to cut grooves in concrete or to cut CMU block. It’s a hand tool, of course, so is not meant for sustained operation.
You tried to cut metal pipes with the grinding wheel?
Pneumatic will drain your air tank rapidly, the compressor will be on all the time, and you’ll have a hard time keeping it going. Unless you have a huge compressor and tank go electric. You can get cutting and grinding wheels for metal and masonry, and attach wire brushes. A good hardware store should have a collection of wheels for use on an angle grinder.
The primary use of an angle grinder is to make sparks. Lots of them. The shower of sparks turns the mundane task of cutting off a bit of rebar into a masterpiece of manly effort. Everyone should have one.
Shit, I’ve been cutting EMT with an oscillating tool. It hasn’t been all that problematic (and easier/quicker than using a hack saw), but I still have a ton to go. Would an angle grinder make things noticeably easier?
I’ve been using a Dremel to take down a lot of nails driven into the concrete wall with a powder actuated nail gun. When that project is over, I think I’ll drive a few more just to make more sparks.
Way easier.
Waaaaaaay easier.
I’ve cut through quarter inch thick stainless steel with a cutting wheel in no time. And I have also cut channels into concrete using that diamond masonry wheel for it as well. It’s an extremely useful tool.
Just to add to Tripolar post, if your compressor and tank are portable, it is too small for a pneumatic grinder.
I also have found that electric are slightly less likely to stall when cutting.
A bench grinder can be used for various odd jobs. Depending on the wheels you install you can use it for cutting, grinding, shaping, sanding, polishing and even sharpening.
I have a dual grinder with a sharpening stone and polisher which I use quite often.
NOTE: Read the metal particles in the eye thread. You should use the skin tight type of goggles when cutting metal to keep the particles out of your eyes. Regular safety glasses can let some of it get by. If you ever get an MRI let them know that you’ve done grinding.