personally I would buy a used one that seems to not have been ran hard. you really have to beat on a rotohammer to kill it. I have one of the smaller bosch rotohammers and have put large bits on it and just leaned on it until it was super hot a bunch of times. If you watch craigslist for a...
one of the other reasons why uphill is considered stronger than downhill on a vertical weld is that impurities/contaminants in the puddle tend to float to the top of the puddle and will get trapped in the weld going downhill whereas uphill they just stay at the top of the puddle. of course...
i use a drill doctor about every other day at work(small fab shop). very slick little tool, beats the belt sander nine times out of 10. try and figure out which angle your particular drill bit is cut at and stick with it. changing the angle on the bit gets wierd with where the grind tapers...
