An update, 2 years later! I fiddled around with this thing 4 or 5 times over that time. It was a $12.00 flea market buy and I realize now that the box it came in probably had all the instructions the thing ever came with. What my issue turned out to be was that, unbeknownst to me, these things came with a spring steel guard for the stone. Mine was sort of welded onto the aluminum frame with that white corrosion you get between steel and aluminum. I got a little po'd messing with the thing because the adjustment screw didn't seem to do a darn thing. I finally stuck a screw driver between what I now know is the guard and the base plate and the guard went flying across the garage. I thought I'd busted it for good, but when I looked down at the stone area it was perfectly obvious what I'd missed. I've looked at at least a dozen picstures on line of these things and read what little is out there on them and I never saw the guard or any mention of it. I'm betting most people lost it around the 3rd use. I suppose I should celebrate my patience and my forbearance for not grabbing a bigger hammer like I usually do, but I feel really dumb. It's okay though, it's a feeling I'm used to!
Ordered some new stones for 3/8" chain, should be good to go now.