Hi and welcome to the site.
I too bought my first grinder this weekend.
I've been using a dremel type for about 15 yrs now to sharpen them on the saw.The biggest problem I've had with this setup is the cost of the stones $10/3 .
The slightest bit of too much pressure and they break right off of the shaft.Sometimes I can sharpen ten chains with one stone,sometimes break 2or3 stones doing one side.:bang:
Anyway,back to the BG.
Got one from harbor freight. Chicago land is the brand name.
Seems to be a very cheap immitation of the Oregon BG,but I was able to sharpen 5 14in chains,a 16in , 2 20s ,a 25 and a 36 in about an hour even though the 3 larger chains require a bigger wheel to be done correctly.I just used the small 1/8 wheel that came with it as these chains were duller than snot and I had nothing to lose.
They all tested ok on a log I have here in the yard.I'm sure they will be better when I get the right wheel.
All in all ,didn't go wrong for $40.I am sure i will be upgrading to the Oregon in the near future,now that I know what they are capable of.
PS A little squirt bottle with water helped to keep from overheating some that were rocked and took a bit more than just a tap with the wheel.