For reference, the Welch 1400 is a bona-fide 2 stage pump with a specified base pressure of 10^-4 torr, good enough for pumping down a small fusor. The 1405 and 1402 have higher capacity, but the 1400 is a lot smaller and lighter. I haven't benchmarked either of my 1400s yet, but I have a little Leybold D1.6B direct drive pump that pulls down my test chamber to about 4 microns through 2 feet of hose.
It is worth pointing out that the direct drive pumps tend to run much hotter than a comparable belt-driven pump, most likely due to the higher RPMs. They also use a different type of oilthan the belt driven pumps. Both K. J. Lesker and Duniway stock pump oils, flushing solutions, and seal kits for all the major brands such as Welch, Leybold, Alcatel, Edwards,Precision, etc.
Richard Hester
Created on Friday, January 05, 2001 9:48 AM EDT by Richard L. Hester