B,
I have been making blades for about six years now and only once in this time did a used Burr-King come up for grabs. The going price at that time was $750. I never got to the point where I could ask if it was variable or constant speed. I couldn't afford it at the time any way.
Ironically and sad to say, about the only time that you may find a quality used grinder on the market is when a fellow knifemaker has "moved on down the road". On a positive note, it is not that difficult to make a grinder if "resources" are not readily available for a Burr-King or Hard-Core. The primary cost involves the motor and contact wheel if hollow grinding. An idler wheel cost between 1/4 and 1/3 the price of a contact wheel. Basically all that is needed after that is pillow block bearings and a shaft which any machine shop can thread for you. If hollow grinding, who needs a third wheel? Leave the whole thing with only two wheels.
The problem arises when versatility is an issue. In other words, if you need to hollow and flat grind, then basically two different machines are needed unless you can flat grind horizontally (I can't). With the attachments available today, specifically from Wilton or Hard-Core, a fairly quick change over is not THAT difficult. Basically, this is the big difference between home built and manufactured machines, other than the price.
C Wilkins
