Just curious on stuff. Are there different grades of grinding wheels that I should be using for different materials such as 1020? Also, since I don't have a notcher yet, I was practicing my welding and also nothcing skills using my chop saw. First question is should I be worried about the saw slowing down when it gets to the end of the tube? Exactly what it is doing is bogging down the last few centimeters before it goes all the way through. Also concerning the notching, could someone tell me the exact way to notch with a chop saw? Thanks in advance.

Chop saws (abrasive disk) cut better thru a small section and do best if there is a small area of the cutter going into the material at a time. Flat plate cuts faster on edge (vertically). If it takes a long time to cut thru the bottom cut, try to turn the piece on edge, or move the piece foreward or backward so the cutter is not plunging thru the whole cut at once.