11/11/18
When I was initially taking the head apart I noticed the spindle bearings didnt sound great. The noise plus my dislike for the ancillary cooling and lubricating equipment convinced me to take the spindle apart for a rebuild. This weekend I got the spindle apart to clean and inventory the parts. I have new bearings ready to go in and will tackle that next. The bearings were definitely contaminated with both dirt and water at some point. The top bearing was the worst, being the least protected and the machine not being cleaned well. I think a lot of material sat on top of the spindle for a long time collecting dust and coolant sludge. The lower bearings seemed to be in ok shape, but weren't ceramic as the parts manual suggests. They were likely replaced at some point but from what I can tell about the markings on the bearings, they weren't replaced at the same time which means one of the bearings has likely been in and out a few times. This is problematic from a cleanliness standpoint and also that the bearings arent a matched pair. Most P4 bearings are going to be very tight on tolerances so buying a matched set isnt super critical. In any case, both bearings came out.
The drawbar was next and, as you can see in the photo,s was quick a shocker. 10 or so of the 131 belleville springs were completely shattered. Im glad I took the time to dig this deep now. It would have been a let down to have poor finishes right out of the gate once the machine is running. Without a legit drawbar force tester finding the problem could have taken some time and led me down some wrong roads. New springs have been ordered. McMaster of all places ended up being the least expensive. Ill be replacing the whole stack.
11/12/18
Tonight I got the spindle spotless and ready for rebuild. Part of that process meant lubricating the bearings. This spindle has two angular contact bearings up front and a cylindrical roller bearing at the rear. Its very important to get the proper amount of grease in each bearing. I learned all I could from this resource:
https://highspeedtechnologies.com/how-t ... gs-part-1/ (This is just the first of six parts, all of which can be found on their blog).
If you're interested into what goes into rebuilding a spindle this is a good primer. I spoke with the manager on the phone a few weeks ago for some input and they were very friendly.
I bought some Kluber Isoflex 15 online. I think the 50g tube was about $35. You can see in the photos I sucked the proper quantity for each bearing into a syringe. You can buy a prefilled syringe from Barden if youre so inclined.
For the exact quantities for each bearing I referenced NSK's documentation about greasing high speed spindle bearings. For the two front angular contact bearings I needed 1.7 cubic cm each. For the roller bearing I needed 1.4.
The bearings are now sealed in bags to keep them clean until installation.
11/13/18
I got the spindle back together today! Actually was a lot easier than I anticipated. I stuck the main shaft in the garage freezer all day. The bearings just slid right over the shaft with the perfect amount of friction. The cold shaft chilled the bearings by the time I got the sliding the whole assembly in the housing. Slid right together and spins just incredibly. I also got the bellevilles in today and coated them with anti-sieze. Loaded the drawbar up and it popped right in.
Of course, this is no guarantee itll pass the break in procedure but everything is well lubricated, well fit, and very clean (dont let the wear from 31 years of hard use fool you. I could eat off of this thing) Here's hoping. I got a thermometer unit with dual thermocouples. One will go at the top near the roller bearing and the other will go at the nose close to the angular contact bearings. The idea is that you increment your way up to full speed in 500RPM increments, waiting to increase at each level until the temperature of the bearings plateaus and then dips. Once it dips, you go up another 500RPM. This was supposed to be a 13k rpm spindle. Ill be happy if I can get it up to 9-10 which is probably prudent with the switch to grease and dropping the chiller.
11/15/18
Christmas came early. Fedex still has two of the drives. But all the motors are here. So far Im pretty impressed. These are from a company called Bergerda - BGD for short. Everything was very well packaged. Documentation is complete although a bit hard to understand in place. Im working with the mfg to revise the manuals for better clarity.
11/16/18
I got the x axis ways/table off today. The bond lines are good on the Turcite but wear is uneven. Looks like an oil line was plugged and the front liner is worn about .015". I will be redoing these with Moglice but I wont order material until the remaining ways are inspected.
11/17/18
I cleaned up the table today.
11/24/18
Have I mentioned yet this machine is filthy? I’ll get the head off on Monday and focus will shift to getting the machine base cleaned and painted. I need it finished so I can start getting parts off the floor and assembled on the machine. The tool changer for example is taking up a bunch of floor space and parts bins I need back for further work.
11/26/18
I stripped all the remaining wire and pneumatics including the chiller and oil mist system as well as the way lube pump. Both side cabinets need to come off so the machine base can be painted. If you've ever wondered how much wiring is in a VMC, I can safely say its about 50lbs worth.