I'm in the market for a vacuum pump. The most obvious is the Mastercool found here for $135. Its a 1.5cfm, 50 micron vacuum, single stage. Any recommendations other than this? Will this pump do the job for what I need? Can you buy too small of a pump? Also, I've found a few other pumps on ebay. They will list in mm of mercury the vacuum it can pull. Is there any way to convert mm of Hg to microns? I also found one locally on Craigs List for $50. Am waiting to find out the horsepower, strength of vacuum. Recommendations on used vacuums?
The 1.5 cfm pump is ok for automotive work, but i would recommend a 3-5 CFM just because the extra cost isn't much when factored over the life of the pump. The extra capacity is there if you need it.