My main grinder is an oregon 511AX but I got one of the HF units on sale and then applied a 20% off coupon for a total price of $24. i got it for just doing rakers so I won't need to change wheels on my main grinder. The wheel it comes with is too thin (1/8") for 3/8"-pitch, or rakers, so I ordered a 1/4"-wide wheel from Bailey's. I did get to spin it and the motor seems to have plenty of power for the thik 1/4" wheel. The largest wheel the HF unit will take is 4-1/4" so I bought the 4-1/8x1/4". BTW, the arbor hole is the standard 7/8". It's angle is fixed at 60 degrees but you can do the other angle up to 35 degrees or so. You also can't do a vie-tilt angle other than 0 degrees (90). This is ok for Stihl chain and others but Oregon calls for a vise-tilt of 10 degrees. I still haven't set it up yet. Just dumpster-hopped and found a discarded pedestal stand at work last week for it but can't give you true feedbak yet.