After spending the last couple days spend ripping the drive portion of my new milling machine apart to find the source of a horrid noise that it made during operation, I finally found the source; it is both better than I had feared, and worse than I had hoped.
It all came down to the the lower pulley support bearing which sits under the lower half of the front split pulley, right between the break pads. The bearing had seized, and was spinning on the shaft, causing the noise I was hearing, as well as a lot of wear on the shaft; the "very clever" folks who previously owned this machine must have been running it for quite a while like this. I lucked out in that the bearing is a run of the mill deep groove ball bearing (6010), $10us for an el-cheapo, $30 for a fancy name brand.
Now we get to the "worse than I hoped" part. Because the machine had been running for so long like this, the shaft (well, the bearing actually presses onto a hub on the lower split pulley) is so worn that the bearing moves freely. As an aside, I think that is why the noise is more like a rattling than a squealing; I think the gap is large enough now that the shaft assembly was precessing inside the bearings inner race (ker thump ker thump ker thump).
This is really annoying.
So, my task now is to figure out how the heck to get this thing back together. I have a couple possibilities in mind. But I'd like a second (third, fourth, fifth...) opinion.
Option A: Remove the variable speed drive, build up a hub from mild steel, and add in some fixed pulley. The motor is 3 phase, and I have a VFD, so I would not loose variable speed, but as somebody else pointed out, with that approach I loose some torque on the low end.
Option B: Turn the existing hub down to remove the damage, then press on a mild steel sleeve. I like this, but the hub is part of a pulley that I don't think I could turn on my lathe (I have a little 7x14). I could try doing it with a boring head on my X2 mill, it may be doable. I could of course pay somebody to do this part... maybe that's an option. Maybe this is the "excuse" I need to upgrade my lathe as well, though my wallet is still smoking from recent purchases, and the holidays are coming up...
Option C: Add material to the hub to build it up (welding wire, turcite, bronze brazing material?), then turn to the desired size. Again, small lathe may require outsourcing/doing the work on another machine
Option D: Try to source a new pulley. It's possible the grizzly models are similar enough that I could just get a new one. Not sure how to be sure without actually buying one.
So anybody have any better (brighter) ideas. My current favorite is B.
It all came down to the the lower pulley support bearing which sits under the lower half of the front split pulley, right between the break pads. The bearing had seized, and was spinning on the shaft, causing the noise I was hearing, as well as a lot of wear on the shaft; the "very clever" folks who previously owned this machine must have been running it for quite a while like this. I lucked out in that the bearing is a run of the mill deep groove ball bearing (6010), $10us for an el-cheapo, $30 for a fancy name brand.
Now we get to the "worse than I hoped" part. Because the machine had been running for so long like this, the shaft (well, the bearing actually presses onto a hub on the lower split pulley) is so worn that the bearing moves freely. As an aside, I think that is why the noise is more like a rattling than a squealing; I think the gap is large enough now that the shaft assembly was precessing inside the bearings inner race (ker thump ker thump ker thump).
This is really annoying.
So, my task now is to figure out how the heck to get this thing back together. I have a couple possibilities in mind. But I'd like a second (third, fourth, fifth...) opinion.
Option A: Remove the variable speed drive, build up a hub from mild steel, and add in some fixed pulley. The motor is 3 phase, and I have a VFD, so I would not loose variable speed, but as somebody else pointed out, with that approach I loose some torque on the low end.
Option B: Turn the existing hub down to remove the damage, then press on a mild steel sleeve. I like this, but the hub is part of a pulley that I don't think I could turn on my lathe (I have a little 7x14). I could try doing it with a boring head on my X2 mill, it may be doable. I could of course pay somebody to do this part... maybe that's an option. Maybe this is the "excuse" I need to upgrade my lathe as well, though my wallet is still smoking from recent purchases, and the holidays are coming up...
Option C: Add material to the hub to build it up (welding wire, turcite, bronze brazing material?), then turn to the desired size. Again, small lathe may require outsourcing/doing the work on another machine
Option D: Try to source a new pulley. It's possible the grizzly models are similar enough that I could just get a new one. Not sure how to be sure without actually buying one.
So anybody have any better (brighter) ideas. My current favorite is B.
