I have a Proxxon IB/E, but it is not rigid enough to use as a tool post bore grinder, as it only has a single bearing. I picked up a box full of FAG 7200 AC's off Ebay, so I decided to design a rigid spindle around them.
Hi Cary,
The cups are a located radially in the housing, but axially by the caps. Bearing preload has been set by shimming the cups. This was the way the angle gearbox was, and I figured a nicely aged cast iron block with precision bore is a better housing than something I'd hack together.
I need to post some pictures of the physical parts. The picture shows the current physical condition.
I have not decided on the bearing/ pulley retention system for the rotor yet.
Since there is a shoulder at the bottom of and shaft and a spacer between the two inner races, the the whole rotor will be retained from the top. Whether to turn a thread and use collar nut, or use a taper locking set up which includes the drive pulley is open.
This bigger spindle is on hold because I am more interested in the little one at present. My projects tend to take a rather meandering journey to completion.
I need to go see a friend and get a valve spring so I can finalise that design. The spring will preload the upper, floating bearing. The design is based on Herbertkabi's recommendations here.
http://www.cnczone.com/forums/showth...t=12184&page=5
So far I have just made the main spindle shaft (2x - the first one I messed up), and the bearing spacer.