Hi Tony,
I`m surprised that noone has jumped on this question yet.
The Oregon 511A style grinder offers good bang for the buck in terms of reliabilty and performance, but it does have a few significant idiosyncracies that you will have to learn to deal with, such as the fact that the wheel is uni-directional so you are going to have a burr on the outside of the left cutters and, and centering the wheel for symmetric grinding can be difficult with a new wheel and is impossible as the wheel gets smaller because of the long arc travel of the head. Using a borazon wheel helps with this problem. The 511A does have a tilting chain vise for round chisel chain.
The slightly more expensive hydraulic auto clamping version of the 511a does not have a tilting vise and does have all of the 511`s other inherent shortcomings.
The Maxx grinder also has a long travel head and would have the same centering problems as the 511A if it weren`t for a sliding table that the vise rides on. This table feature does require a small amount of consciousness to get just right for repeatability but the motions become automatic in time. For some unknown reason, some of the Maxx grinders come through with centering problems severe enough that they require fixing. If you buy one from Jeff S. he will test it before it leaves his shop and will perform a factory authorized fix if needed. The sliding table also permits grinding a 10° down angle on the topplate and the way that the vise rotates allows you to grind so that the burr is always on the inside. The Maxx also has an auto clamp feature that is mechanical, foregoing the weakness of the hydraulic system.
The Silvey 510 is probably the best round grinder that I`m aware of. Centering has never been an issue and I have two so I`m inclined to believe that they`re all just as good. They are also bi-directional and have a 10° angle for round chisel built in. The Silveys are built like tanks and will last forever. The downside is the cost. They are about $700 plus shipping which is high because of the weight.
For the cost of one Silvey you could have two Maxxes, one for .325 and lo pro and another for 3/8 and .404. The Maxx and 511A can also be made to square grind in a sense as was illustrated by Gypo`s thread a while ago. I believe that the sliding table of the Maxx gives you more flexibility for square grinding. The Silvey won`t square grind.
Russ
