G4000 Spindle Bearings

[chip maker]

So, It's been coming for a while and with it being winter with time on my hands thought it was time to replace the spindle bearings. My lathe is a 1999 bought it in 2000 so have had it for a while. Since I had it always seemed to have a bit more bearing noise but didn't give it a lot of thought but seemed to be getting a lot noisier. So before doing this job did some reading and found that many people used the Lucas Red N Tacky grease instead of the oil that Grizzly uses. There is really nothing to hold any oil in these bearings seems to make since to me to use grease. I have an automotive back round having my own business for 30 years so with replacing wheel bearings and packing with grease all those years this just made since. So, the job is now done and can't believe how quite it is, bearings may have been bad right from the start. My question is now that these are greased how often should I be adding grease??? After reading it seems many lathes use grease instead of oil so what do you do for keeping them lubricated as these bearings are not fully sealed and don't have seals like cars do. If adding grease once in a while how much do you add and how often? Of course, I don't use this lathe daily but just want to keep it in good shape. Thanks for the help I know that someone on this site must have also been down this road as well. I did notice that after the break-in there was a little grease coming from behind the slingers on both sides but not a lot. Thanks Again

 

[KevinM]

The daily oiler routine includes lubricating the spindle bearings with oil.

 

[chip maker]

Yes, I knew that but now I have replaced the bearings and doing the replacement I have gone to grease rather than a daily oiling. Oil was always a bit messy because the bearings are not sealed in any way, so oil builds up and runs past the slingers this is one of the reasons I decided to go with the bearing greasing rather than oil.

 

[pacifica]

So, It's been coming for a while and with it being winter with time on my hands thought it was time to replace the spindle bearings. My lathe is a 1999 bought it in 2000 so have had it for a while. Since I had it always seemed to have a bit more bearing noise but didn't give it a lot of thought but seemed to be getting a lot noisier. So before doing this job did some reading and found that many people used the Lucas Red N Tacky grease instead of the oil that Grizzly uses. There is really nothing to hold any oil in these bearings seems to make since to me to use grease. I have an automotive back round having my own business for 30 years so with replacing wheel bearings and packing with grease all those years this just made since. So, the job is now done and can't believe how quite it is, bearings may have been bad right from the start. My question is now that these are greased how often should I be adding grease??? After reading it seems many lathes use grease instead of oil so what do you do for keeping them lubricated as these bearings are not fully sealed and don't have seals like cars do. If adding grease once in a while how much do you add and how often? Of course, I don't use this lathe daily but just want to keep it in good shape. Thanks for the help I know that someone on this site must have also been down this road as well. I did notice that after the break-in there was a little grease coming from behind the slingers on both sides but not a lot. Thanks Again

skf lgmt2 , mobil ep-2 , or Kluber nbu-15( super expensive) 1/4 to 1/3 full. When grease gets low add more. Something like this: https://www.amazon.com/Plews-05-037-Grease-Injector-Needle/dp/B000FMO6XU .

 

[chip maker]

Maybe I didn't come across right, I have the bearings installed, packed with grease instead of using oil and everything is fine. I made an adaptor to put the grease in if needed but needed to know how often to add grease? Is there any rule of thumb or do you just guess?

 

[T Bredehoft]

The "rule of thumb" is to oil them daily. Since you've greased them, no "rule of thumb" applies. Grease when they get noisy.

 

[Cadillac]

If in a sealed area then you don’t want to keep adding grease. Over greasing a bearing will ruin the bearing. Once greased it should last years and years.

 

[KevinM]

For the last 45 years I have seen cars with greased front tapered roller bearings and +200,000 miles have perfect bearings with no maintenance. I have seen many toasted bearings fail due to being WAY too over-tightened. Well over 99% of bearing failures that I have seen have recently had the brakes serviced by an unqualified person.

 

[mikey]

In general, spindle bearings are "packed" to about 25-30% of their capacity. If you pack them full like you would a wheel bearing, they will typically overheat and the bearing may fail. After packing to about 25% and adjusting preload where you want it, the spindle is run at medium speed for about 1/2 hour to distribute the grease evenly. Temp is monitored and should generally not rise above about 100 deg C.

With regard to frequency, there is no standard that I am aware of when switching from oil to grease.

 

[chip maker]

mikey Thanks and I did do the break-in, and all was well with temp so should be good to go.
KevinM You are correct I to seen cars go many years without getting bearings repacked the only thing with cars the hubs had seals to retain the grease and the lathe is open with an outside slinger and inside cup retainers. I am guessing that this works well for this application because there is no water or anything else to wash out the grease.
When packing the bearings, I did find that the Red n Tacky grease is really tacky so guess it will be staying in place.