Loading quill bearings

[toolingjim]

When I used to build injection molding spindles with tapered roller bearings, we set them up DRY so they could just barely be turned by spinning them using a lever with a six inch length. Then we lubricated the bearings. This was based on the idea that opposed tapered roller bearings never wear tighter, just looser. Our spindles never got over 400 rpm or so, but were under tremendous pressure.
From another source. I read long ago that one fellow converting Enco (remember them?) milldrills to CNC got tired of the crappy setup of chinese quills. Based on his methods, I would suggest the following: pull the quill and tear down the spindle completely. Wash everything clean. Check for burrs and wear and correct as needed. Reassemble with a good grease. He said the setting was a bit hit and miss: I would suggest tightening everything finger tight, giving the spindle a sharp rap with a plastic or rubber mallet on both ends to push the grease out of the way, and retightening by hand or gently with a spanner. Repeat a couple of times until the things seem to be stable and firm. He then went on to say he ran the spindle at high speed for a couple of hours to test. I would first run it at 300-400 rpm for a couple of minutes just to seat everything and push the grease out to where it belongs, then run it full speed. The quill will warm up, but his criteria for proper setup was that after two hours, the quill should never get so warm that you could not rest your hand comfortably on it. Pick a time when you can check that quill every few minutes during the runoff. If it gets hot fast, shut down and loosen. If it shows any loosness after the run, tighten a bit more and rerun. If thermal expansion affects the spindle more than the quill housing, the spindle bearings could lose preload. Not probable, but possible.
Based on my experience with my milldrill, they do get warm at high speeds, and my millldrill is well seated and old enough to vote.
Hope this helps.

 

[BundyBearsShed]

The rule of thumb I use for any tapered roller bearing is if the cones face each other set at zero to two thou pre load on a new bearing. Now to gauge 0.002" you can indicate the adjusting nut and see how much of a turn will give you this 0.001 or 0.002" after you have found zero. . With some preload the machine shaft will expand slightly with heat of use and the bearings will wear slightly over time so the preload will allow for some of this. On a bearing with the cones facing away from each other it was often zero to 0.002" end float with the same thing in mind being the expansion of the rotating part with use. Keep in mind Im a big tractor and gearbox fitter so what Im talking of is on much larger gear but I thought it might be helpful anyhow.

 

[William May]

The rule of thumb I use for any tapered roller bearing is if the cones face each other set at zero to two thou pre load on a new bearing. Now to gauge 0.002" you can indicate the adjusting nut and see how much of a turn will give you this 0.001 or 0.002" after you have found zero. . With some preload the machine shaft will expand slightly with heat of use and the bearings will wear slightly over time so the preload will allow for some of this. On a bearing with the cones facing away from each other it was often zero to 0.002" end float with the same thing in mind being the expansion of the rotating part with use. Keep in mind Im a big tractor and gearbox fitter so what Im talking of is on much larger gear but I thought it might be helpful anyhow.

Bundy, I watch a lot of your "Shed videos"! They are excellent! (If anyone is interested (which should be everyone on THIS site, look at "Bundy Bears Shed" for some very interesting and entertaining videos!)

 

[BundyBearsShed]

Bundy, I watch a lot of your "Shed videos"! They are excellent! (If anyone is interested (which should be everyone on THIS site, look at "Bundy Bears Shed" for some very interesting and entertaining videos!)

Thanks for your support.