Basic questions on BG218 Pro Grinder

[Huck]

I am real close to purchasing a BG218 Pro grinder from A.M.Leonard in
the U.S. since there are no dealers up here in Canada,so I can't really check one out in person,so I have a few questions on this grinder.According to Leonards part number,this BG218 comes with a ceramic 8" wheel(blue),now I have read here that a lot are using the Ruby wheel on this machine.Is this the standard wheel that comes with the BG121 Standard grinder?,as this ruby wheel is not mentioned as a replacement for the BG218.These ruby wheels are part#'s RW-12 and RW-101.Which one are you guys using on your BG218?.Do you use one over the other(ceramic vs ruby),or do you "rough" with one and "finish" with the other.Also, how do you keep the blade square to the wheel when grinding so that the cutting edge is parallel to the straight side of the blade opposite the cutting edge.Lastly how do you figure out blade tip speed?(f.p.m.).Thanks for taking the time to look at my post and hope to see your responses.I have learned a great deal here and will continue to use this site for good info!!Thanks,Huck(Canada):)

[weve]

This is what R.B.G. Grinders says about their grinding wheels;

Ceramic - Aluminum Oxide Grinding Wheels. Blue hued color, micro fracture ability. Excellent on very difficult-to-grind applications. Excellent performance at low speed and high speed grinding. The Ceramic Wheel represents a premium product for the user whose applications requires the highest level of quality and maximum product performance.

Ruby - Aluminum oxide Grinding Wheels. Rich ruby red in color, much harder and extra tough. Designed for their performance qualities to sharpen quicker while reducing burn because of their open structure design. The relative percentage of abrasive and bond, and their spacing within the wheel, impart a characteristic known as structure.

The ceramic wheel is on my 2181-P. I haven't used a ruby wheel yet.

[Eric ELM]

I have the 2181-P with the blue ceramic wheel. I have used it for 14 months and measuring from one side to the other of the wheel, it is 1/8" smaller now than 14 months ago. This means it has worn 1/16" off the wheel in a little over a year. At this rate, it would take 16 years to wear down 1". I think most of that 16" was from using the diamond dresser which is needed to keep the wheel flat and clean.