[Source] Spindle Bearings

[Ulma Doctor]

another thing to check is deflection.
put an indicator at TDC on the chuck and insert a 1" x 12" rod in the chuck .
pull up on the rod and push down and note the indicators reading.

if you disengage the belt drive, and the gearbox- you may be able to feel faulty spindle bearings by turning the chuck slowly by hand.
there maybe drag noticed, if the preload is too great

 

[HRgx]

As a new comer here, my first interaction was to ask questions about a tool that came with my lathe. I've gotten all the right answers. As such, I feel that I would like to give back early on. Besides being a journeyman millwright, my expertise is vibration analysis. I run 3 vibration analyzers, my software contains fault frequencies for over a million bearings from various manufacturers. A knowledgeable analyst in your area should be able to pin point what bearing frequency is producing the noise, outer race, inner race, cage or ball spin. When I purchased my new to me lathe, that is exactly what I did as it sat idle for about a year. The mass of the spindle and chuck can cause a flat spot on either the inner or outer race. This is referred to as "false brinneling". You might be able to exchange the service of a good analyst for something that you can provide for him in terms of machining. If and when you find out that you might have to replace a spindle bearing, stay away from Chinese bearings, go with the likes of SKF, FAG or TIMKEN if you can. Hope this helps and good luck.

 

[HRgx]

another thing to check is deflection.
put an indicator at TDC on the chuck and insert a 1" x 12" rod in the chuck .
pull up on the rod and push down and note the indicators reading.

if you disengage the belt drive, and the gearbox- you may be able to feel faulty spindle bearings by turning the chuck slowly by hand.
there maybe drag noticed, if the preload is too great

Although that may be a good check, think of it this way. If there is actually a flat spot on an outer race, it may take a pre-defined amount of spindle revolution to actually have a ball come into contact with it. Could it possibly be a flat spot on the spindle bearing, or might it be a flaw on a gear?

 

[Bamban]

As a new comer here, my first interaction was to ask questions about a tool that came with my lathe. I've gotten all the right answers. As such, I feel that I would like to give back early on. Besides being a journeyman millwright, my expertise is vibration analysis. I run 3 vibration analyzers, my software contains fault frequencies for over a million bearings from various manufacturers. A knowledgeable analyst in your area should be able to pin point what bearing frequency is producing the noise, outer race, inner race, cage or ball spin. When I purchased my new to me lathe, that is exactly what I did as it sat idle for about a year. The mass of the spindle and chuck can cause a flat spot on either the inner or outer race. This is referred to as "false brinneling". You might be able to exchange the service of a good analyst for something that you can provide for him in terms of machining. If and when you find out that you might have to replace a spindle bearing, stay away from Chinese bearings, go with the likes of SKF, FAG or TIMKEN if you can. Hope this helps and good luck.

Sounds good. Unfortunately, my machining is limited to doing stuff for me and supporting the TX junior shooters. My skills would not be that tradeable to anyone. Besides hiring an engineering help to scientifically ascertain the bearing situation, I am afraid I just have to settle for other way to quantify the "noise"

Thank you for the suggestion.

 

[4GSR]

Metric bearings don't use the ABEC system; they use a P-rating. It will come down to how much money you're willing to spend because below P5 (equivalent to ABEC-5) these bearings get expensive. By the way, as the number gets lower the accuracy rating goes up in the P-rating system. For example, a P4 is has tighter tolerances than a P5.........................................

Mike,
Correct me if I'm wrong, the P4, P5 tolerance system is something of modern times thanks to ISO. Up until this time, the ABEC standards was the tolerance system used for Metric bearings and remotely still being used. It has been replaced by the ISO system of measurements. Ken