Spindle Bearings Are Shot Already, After Market Alternatives?

[spalted]

As some of you may know I have had trouble with carve quality from day one.

The Rock chuck was a big improvement, but I saw some photos of some carves right out of the machine the other day and it made me think something was still wrong. I'm just am not getting that kind of quality yet.

I just put a dial indicator on my spindle, very light lateral pressure: 5-6 thousands of deflection. Moderate pressure 7-9 thousandths. I was only willing to accept 1 thousandth.

I had check it with the old QC installed and had huge amounts of run out, (around 12-13 thousandth if I remember correctly) but I never did check it after installing the Rock. Looks like my problem was two fold.

I have not over lubed the shaft or had any heat issues, so I have had bad bearings from day one. I only have 40 hrs. on the machine so far.

LHR is sending me a new z-truck under warranty.

I don't think it will be easy, but I was hoping to check the new bearings prior to installing the truck.

It seems that I have not been the only one to have spindle bearing trouble. I'm sure some of been due to lube in the top hat and some caused by QC vibration.

After all that I do have a question.

Has anyone tried finding an after market precision high speed ceramic bearing to replace the OEM ones? I'm just looking for an alternative solution if z-truck number two does not work out.

[PCW]

spalted,

I know that the ceramic spindle bearings are available. May want to check with Ron Justice (cw_parts@yahoo.com)the maker of the Rock Chuck because I'm pretty sure he has a source for the bearings.

I have not tore into a spindle yet but believe the bearings would need to be pressed in with a arbor press.


As some of you may know I have had trouble with carve quality from day one.

The Rock chuck was a big improvement, but I saw some photos of some carves right out of the machine the other day and it made me think something was still wrong. I'm just am not getting that kind of quality yet.

I just put a dial indicator on my spindle, very light lateral pressure: 5-6 thousands of deflection. Moderate pressure 7-9 thousandths. I was only willing to accept 1 thousandth.

I had check it with the old QC installed and had huge amounts of run out, (around 12-13 thousandth if I remember correctly) but I never did check it after installing the Rock. Looks like my problem was two fold.

I have not over lubed the shaft or had any heat issues, so I have had bad bearings from day one. I only have 40 hrs. on the machine so far.

LHR is sending me a new z-truck under warranty.

I don't think it will be easy, but I was hoping to check the new bearings prior to installing the truck.

It seems that I have not been the only one to have spindle bearing trouble. I'm sure some of been due to lube in the top hat and some caused by QC vibration.

After all that I do have a question.

Has anyone tried finding an after market precision high speed ceramic bearing to replace the OEM ones? I'm just looking for an alternative solution if z-truck number two does not work out.

[spalted]

Thanks Dan,

I'm sure the bearings would have to be press fit.

I took off the Z truck this afternoon. I can read the bearing numbers on the dust shields. I should be able to find them from one of my industrial supply houses.

[CarverJerry]

Are they bearings or bushings? @22K rpms I can see why they use ceramic and not steel.

CJ

[PCW]

Please let us know what you find out.


Thanks Dan,

I'm sure the bearings would have to be press fit.

I took off the Z truck this afternoon. I can read the bearing numbers on the dust shields. I should be able to find them from one of my industrial supply houses.

[spalted]

I'm not 100% sure, but I assume they are ceramic hybrid ball bearings.
Ceramic balls with steel races.

I'm going to try a couple of my suppliers in the next few days and see what I can find out.

LHR is sending me a replacement Z truck, but I wanted a back up plan if the new bearings don't meet my tolerances. I seem to be a little more picky than my friends in Indonesia and Taiwan that made my current bearings.

I had a similar situation with my shaper too, after I replaced the spindle bearings in it everything has been fine.

[Jeff_Birt]

The stock bearing are a good quality ceramic ball bearings. The #1 reason for them to go bad is the grease being flushed out by excess flex shaft lube. You can also put a lot of undo wear on them by using the wrong bits, having a bad spindle shaft or perhaps the bearings were just defective.

Generally the bearing itself is not the reason for the failure, it is something silly we do as operators (speaking from experience here.) You can always find a set of ABEC 7 bearings that will fit but I don't think the extra expense will get you any better performance or life.

[spalted]

Thanks Jeff,

I didn't want to go that route, but I was just keeping my options open and getting a plan "B" in place.

I also wasn't sure if the bearings were preloaded with a crush sleeve or spring, so I was leery of it for that reason as well.

[Digitalwoodshop]

If it is covered by warranty they will want the old part back.

AL

[spalted]

If it is covered by warranty they will want the old part back.

AL

Yep, they are sending me a z-truck with only a core charge.

LHR has been good about replacing the truck, I explained the situation and they agreed to send a new truck no questions asked.

I have the truck out and I can see the bearings now, one of them is a NSK brand, so it is at least it's a name brand.

Jeff mentioned ABEC 7 bearings, but if I'm reading the bearing numbers correct (and there is a very good chance I'm not) These are ISO 0 bearings that would be an ABEC 1 only.

[Spencemark]

Jeff mentioned ABEC 7 bearings, but if I'm reading the bearing numbers correct (and there is a very good chance I'm not) These are ISO 0 bearings that would be an ABEC 1 only.

Hey, that's good to know.. I think I have dozens of those bearings in a box
somewhere, they came in a box of 'junk' from a yard sale for $1. They're
stuck in the middle of some rollerblade wheels, though.

[Jeff_Birt]

I also wasn't sure if the bearings were preloaded with a crush sleeve or spring, so I was leery of it for that reason as well.


As I recall there is a shim between the retaining ring on the top, but no crush sleeve, etc. The hardest part about changing the bearings is working with the tolerance rings (the wavy bits of metal around the bearings.) You need to be dead sure that the bearing and tolerance ring are perfectly perpendicular to the bore before pressing them in or the tolerance ring will be spit out after a few hours run time.



Jeff mentioned ABEC 7 bearings, but if I'm reading the bearing numbers correct (and there is a very good chance I'm not) These are ISO 0 bearings that would be an ABEC 1 only.


What I said was that spending a bunch of money on tight tolerance bearings will not improve anything. They are using a good bearing for the application.



I think I have dozens of those bearings in a box
somewhere, they came in a box of 'junk' from a yard sale for $1. They're
stuck in the middle of some rollerblade wheels, though.


Don't be tempted to try and use them, they will be cheap steel ball bearings that will die a quick death at 23,000 RPM.

[spalted]

Thanks Jeff,


What I said was that spending a bunch of money on tight tolerance bearings will not improve anything. They are using a good bearing for the application.

I agree with you Jeff, I decided not to go down this road. I'm going to run the replacement and see how it goes. But after I started this thread I kept getting more curious about the bearings and how the spindle is assembled. It's nice to know for future reference.


Quote:
Hey, that's good to know.. I think I have dozens of those bearings in a box
somewhere, they came in a box of 'junk' from a yard sale for $1. They're
stuck in the middle of some rollerblade wheels, though.

Don't be tempted to try and use them, they will be cheap steel ball bearings that will die a quick death at 23,000 RPM.
54 Minutes Ago 07:35 AM

Don't take what I said about the bearings as something "good to know" I'm just thinking out loud here. I'm not even sure I'm correct about the bearing classifications.But I do know I would follow Jeff's advise, I'm positive he is correct about your bearings.

There is a lot more to choosing the correct bearings than the just the size. The materials, internal configuration, seal types,tolerances,expansion coefficient, load rating ................ on and on.