Colombo Extreme Makeover Edition....Lotsa Pics
Well today was the day...after 5yrs of excellent trouble-free service it was time for me to treat my Colombo to some fresh bearings. It has served duty cutting everything from hardwood to carbon fiber and aluminum without ever letting me down.
I bought a set of matched sheilded ceramic bearings for the bottom and a sealed bearing for the top from Ekstrom. The bearings that were in the spindle from Colombo were high-speed non-shielded or sealed bearings. These are really not up to 'drill duty', but the replacement ceramic ones I believe are. It won't make my bot a drill press, but it will make me feel more confident about drilling alot of holes.
The following pictures are not meant to be a tutorial on how to change your spindle bearings, just to give a glimpse into the inner workings of the spindle, since I doubt most have ever had the chance to. While I am a firm believer in, "What one man can do, another can do." - keep in mind that this is precise work that requires a delicate touch, mechanical & electrical skills and a 6th sense on how not to ruin your $4,000 spindle...
I pulled the spindle & T-rail off in one go. You can see that this is a perfect time to do some maintenance on the hard to reach spots. Looks like a mixture of oil reside & Trupan dust (L), but in my shop it could be anything! All of the bearings, geartrain & surfaces will be cleaned & lubed before re-assembly and the 5HP spindle without it's wiring or T-rail (R)
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This is the top of the spindle with fan removed (L) and AL dust & end cap removed to expose the top bearing (R)
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This is what the spindle looks like with it's main shaft removed (L) and the shaft with bearing lands still attached (R)
Top bearing is on far right end of shaft. It is much smaller than the lower set.
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The spindle case with windings was put aside since all of the bearings reside on the shaft.
Here's a few more pics of the shaft with the old bearings on it:
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Look carefully at the 2 above pics...you will notice several recognizable parts! There is much more detail to these pics than can be show @ this resolution, such as labyrinth seals on several sections of the shaft to keep dirt & debris out of the bearings. If you don't assemble with kid-gloves, you can break these seals...and it quickly becomes a sad day. Thankfully I didn't do that!
Here's a shot of the old bearings (L) and a new sheilded ceramic one (R)
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There's a little more than just pressing off & on bearings. The bearings must mate to each other in a particular orientation, including(!) face to face alignment, inner race clock alignment and outer race clock alignment. I marked the bearings with a red Sharpie & put a line on the shaft to help align the inner races. The outer ones have marks from the factory clearly visible...the inside has a * on the race that you can barely see! You'd only know it was there by looking for it!
I didn't take pics of the pressing or assembly (or giving the parts a SafetyKleen bath), but we tested it at 60Hz (3,600 RPM) and it was silky smoooooth & quiet, unlike the old set. It took about 4hrs total to remove the spindle, clean & swap out the bearings. I'll probably spend the better part of an hour tomorrow re-wiring, cleaning/maintenance & assembling the spindle on the bot again. I'm a little tired tonight, so I will clean up the bot, adjust & re-assemble the spindle tomorrow. It should be rip-roarin and ready to go for another 5 years!
-B
