My mixer made a grinding noise, so i oiled it

I am assuming that when you oiled it you merely squirted oil in various places without actually taking the mixer apart. You probably did a good thing if....if....it corrects the grinding noise...but...oil is not only an excellent lubricant it is also a very good insulator and if you got oil into the switch area where it turns on then you may have got oil inside and it can be insulating the place where electrical contact is made. For a possible quickie solution you might try to use something to eliminate the oil that may have got into the switch. Best thing is probably to go to Radio Shack and buy their contact cleaner spray can and use it on the switch. That stuff is real expensive though. A cheaper solution might be to use isopropol alcohol if you have some handy or even spray carburetor cleaner as both of them will completely dry quickly. Be sure to unplug the unit before doing this and allow it to completely dry before plugging back in. You can do all of this without taking anything apart. If it then runs ok then I suspect the grinding noise is still there as the gears inside probably need a little grease. If you want to go that trouble you can remove screws and open the case up...carefully...and put a dab of auto wheel bearing grease on your finger and rub it into the area where the gear teeth are. Do not use a big gob of it ... just a little amount is all needed. If you do not have any grease handy you can use vasline if you have some in the house. If the mixer did not turn on after the above dousing of alcohol etc. from the outside then you may need to do the cleaning directly on it from inside...so if you do take the mixer apart spray the cleaner directly inside the switch. When you take the mixer apart do not remove the shaft/motor/armature or other parts...remove only the cover and enough to do the repair. The possible problem is that if you take it apart too much it will be difficult to get back together particularly if you remove the armature and contact area of the commutator where the carbon brushes are. While inside there though look at the copper commutator area where the tiny carbon brushes make electrical contact. They may be pitted or not allowing the brushes to make good connection. To correct this you can spray contact cleaner directly onto the contact area to clean it. Let it dry and reassemble and the mixer should run ok. If the mixer is very old and been used a lot then the contact area of the commutator may be worn so badly that it does not make good contact with the brushes or the brushes may be worn down so much that they no longer make good contact. In that case you would need to actually remove the armature assembly...what I told you not to do above if you are not too good at reassembling things. Once the armature is removed it is easy to take some fine grit sandpaper and clean the copper commutator making it clean and bright copper color like new again. Also if the carbon brushes are almost totally worn down you probably can find some new ones that will fit ok by taking the old ones to your local hardware store as many of them stock carbon brushes nowadays. If you do all this and are able to reassemble the mixer then it should be just about as good as new again. Hopefully you do not need to go to all the trouble of the major disassembly though. Good luck.