For the past several months i have been in the process of retrofitting a bridgeport series 2 interact 4 cnc mill. The mill was made in 1989 and has sat for more than 8 years now as the control system was dead. I thought that the machine was mechanically sound as it appeared to have very little wear, however i am slowly learning that looks can be deceiving. The spindle must had gotten moisture into the bearings at some point or they simply rusted from sitting so long without moving because the spindle was basically locked when i started trying to manually turn it. I got the spindle to turn after a bit of massaging but there is a pretty substantial growl coming from one or more of the bearings.
After pulling the spindle cartridge from the mill i also found that approximately 50 of the 120 belleville springs in the drawbar had been reduced to pieces. At this point i realized that i would likely need to replace the bearings, have the taper reground, and the belleville washers replaced (and the drawbar force reset). The problem is that this is a fairly large spindle (~5.25 inches in diameter), with triple 7014 series bearings in the front and a single 6012 bearing up top. Apparently these bearings are expensive and i have received quotes ranging from $3,000 to $6,000 to do the full rework.
Its not so much that i am a cheap bastard, its just that this mill will only be used for hobby work and it honestly isn't worth as much as its looking like its going to cost to repair (given how cheap newer, nicer machines are selling for on ebay).
I am confident that i can replace the belleville springs and fabricate a tool to properly set the drawbar force myself. What i really want to know is if i can press the spindle apart, clean and regrease the bearings (and possibly replace the top 6012 bearing if it is the one causing the noise), and reassemble it. I know that this is unacceptable for anyone looking to get reliable, long life from their spindle and that NC_CAMS is probably rolling over in his grave right now, but honestly for how much i will be using this thing (maybe 1-2 hours a week, tops) i really would like to know if this is possible and what you all think. I have the tools to do this properly but am not sure what the results will be. At this point i can't see how i could make anything worse as the spindle won't work as is.
Does pressing the quill out of the spindle brinell the races and destroy the bearings? Is there any tricks to disassemble the spindle without destroying the bearings?
I have done a lot of reading about bridgeport's original bearing assembly/selection and i am also wondering if this will seriously affect the run out (ie: if the bearings aren't dead concentric and the outer races are not installed in the exact position as where they were removed).
I have included pdf's showing the cross section of the spindle. I really appreciate any and all advice.
Noam