Grizzly G0935 Spindle Bearing Surprise

[jdeng]

well that was a hoot. only realized after getting the new ACB that the old one was put in upside down. Seems as good an explanation as any.

One other adventure: I was thinking that I already had the thrust bearing so I'd just install it, then turn a new spacer to see how it runs. That bearing was from mcmaster and had two different sized washers! 30mm and 32mm. Can't catch a break so I went with the stock (not to drawing) assembly.

TIR is between .0004 and .0007. Far better than I can do. Google tells me to check the temp of the spindle after awhile to make sure preload is fine. Are there any other methods?

Finally worth noting that Grizzly has been slow to respond here. It took them awhile to agree that my spindle was different than their drawing and now we're waiting for them to "contact the factory". Will share any news if I get it.

 

[Ischgl99]

The google method is what I use, more details on how I do it is as follows. You don’t need much preload on the bearings, mine are usually light finger tight on the locknut. Rotate the spindle by hand to make sure it is turning freely. Extend the quill and measure the temperature on that and not the housing. Run the spindle at a low speed first and make sure it doesn’t get hot. Cool to slightly warm to the touch is good. If running hot, loosen the preload. Run at a higher speed, say 2,000 rpm for at least 15 minutes and check temp during that period to make sure it is not getting hot. A contact thermometer on the quill itself is best place to check the temp and make sure it levels out. IR thermometers use an optical sensor and will read the temperature of the reflection, so that is not a good choice for measuring reflective surfaces. If still good, increase speed and check again. At full speed, it should get warm, not hot to the touch. That is usually in the 120-130f range. 140f is usually the temperature where you can’t keep your hand on it for more than a few seconds. The important part is to make sure it levels off after running for at least 15 minutes, could take a bit longer since the quill needs to heat up too. If the temperature keeps increasing, it’s too tight.

 

[jdeng]

Are there any indicators if the preload is too light? I ask because I started the break-in last night and I could hear the balls rolling.

After setting my preload, The spindle turned freely about a 1.5 turns and had no discernible play. But I didn’t like the noise I was hearing so I kept the Rpms super low (300) for 10-15 minutes. Anything higher than that and the noise returned.

Wondering now if I didn’t slather enough grease in the ACB.

 

[Ischgl99]

If you hear the rolling elements rolling as it turns, then your preload might be too light, or the bearings were not fully seated before tightening the nut and you pressed them further in and removed the preload. Try tightening it a bit more and see what happens. Even without any grease, you shouldn’t hear balls rolling around.

Spindle bearing don’t need much grease, typically about 30% full. If you do much more than that, you can get overheating at higher speeds.

 

[jdeng]

makes sense. Would I see wobble, particularly at low rpms if the preload was too light? with the runout being pretty good (not amazing from what I've read) I also have to consider that I did something else that was dumb. back to the wrenches to "do it the right the third time"

 

[jdeng]

Also check out this reply from McMaster:

We have checked our stock and researched this ball bearing (7806K718). These bearings are designed to have one side measure 32mm.

One side of the rings is made to be the shaft fit and the other side is the housing fit. This way you get a loose fit housing/tight fit shaft and tight fit housing/loose fit shaft.

One side should be 29.99-30mm and the other side should be at least 32mm for this size bearing.

I had no idea! Certainly not in the part drawing or listing.

 

[Ischgl99]

Would I see wobble, particularly at low rpms if the preload was too light?

possible, if the balls are unloaded, then it could move around more than it should.

Also check out this reply from McMaster:

I had no idea! Certainly not in the part drawing or listing.

I checked my Schaeffler bearing catalog and that bearing does have a 30mm side and a 32mm side. This is a single direction design, if both rings are 30mm ID, then it can support thrust loads in either direction. The 30mm disk would be the side that gets mounted up against the shaft shoulder, and the 32mm side is in the housing recess.

 

[jdeng]

Well, I've tried with zero preload, low preload, and heavy preload and I get the same result. Video below with the grinding starting around 1:10
mark. Maybe my reputable ebay seller was not so reputable.

I'm going to dis/reassemble everything and give it one more go

View attachment 20240906_5903.mp4

 

[Ischgl99]

I'm not sure what that is, sounds like something may be loose. Could it be in the pulley region, or does it sound like it is near the nose? You can use a screwdriver as a stethoscope to try and isolate the noise. If you haven't done that before, press the driver end on the point you are inspecting and the handle up against your ear, move around to several locations and listen for differences. You should be able to tell where the noise is originating from that way.

 

[jdeng]

good idea. i have a steth that i use on a crumbling jeep that will do the job.

I'm pretty sure it's coming from the nose but can't hurt to double check. it's in pieces at the moment and will jump back in tomorrow. thanks for the continued assist.