How much grease should be in new bearings?

[Mikyg]

Hi guys and girls, i’m at the beginning of stripping and rebuilding my NEQ6 pro and have just started greasing the new bearings with superlube grease. Can anyone tell me how much grease i should be putting in?, as the videos I’ve watched on youtube said pack them out but other advice says less.

 

would you say this in the image is too much and if so does anyone have any pictures of the right amount? Thank you

[blinky]

The SKF bearings i got for my EQ6 were sealed ones and needed no grease added - did you get sealed ones and remove the dust seal to add the grease?  I would say thats too much but Im in no way an expert!  I think a little goes a long way....

[Mikyg]

Yes i removed the dust inserts, cleaned and regreased but i’m getting so many different views on this, some saying pack hard and some saying too much lol

[blinky]

I know, loads of different people do different things, I would say go the manufacturer - it is or was.... sealed for life so there should be no need to remove the seal and add grease.  That being said, I would not bin it or anything, just remove some of that grease and it should be fine

[Mikyg]

I read that The caps are supposed to be removed so you can regrease them every so many years. I’m deffinately not buying new bearings every two years 😂 yes thats what got me worried, the manufacturer had put a lot less in

[newbie alert]

2 minutes ago, Mikyg said:

I read that The caps are supposed to be removed so you can regrease them every so many years. I’m deffinately not buying new bearings every two years 😂 yes thats what got me worried, the manufacturer had put a lot less in

You can over grease a bearing for sure 

[1parsec]

Over packing is more of a problem in normal applications where the shaft and inner race of the bearing is spinning at 1000's of rpm. 
The grease heats up and becomes more of a liquid and the pressure of the balls running in the grease forces the grease passed the seals.

But for a slow moving telescope mount it isn't much of a problem.  Packing the bearing full will increase the drag of the axis, which mechanically isn't
a problem for reliability but might cause tracking issues ??

When greasing this bearing I would leave 50%>75% space for the grease to move around the balls.

[billhinge]

I previously re-greased my RA bearings with ws2 in oil some years ago, it sticks to anything and bonds to the surface material.

I just spent £80 (cheap old stock Fag branded bearings from ebay) on 2 x Abec-7 7007 angular contact bearings to replace the large 6007 for my RA drive plus new needle bearings. I had already replaced the worm bearings with ceramic abec 7's (which I greased with ws2 as well)

But having a think recently while buffing a worm wheel, the question is why? (I like you read most of the previous hypertune articles online and just followed them)

Surely if the clutch is locked then the only bearings moving are on the worm and the motor? Wouldn't they be the only bearings affecting PE?

Secondly, several academic essays I read say a  mount should be smooth to turn but stiff enough not to be prone to vibration and external factors like wind etc, so maybe thicker grease is a benefit there?

http://www.mesu-optics.nl/mesu200_en.html 

https://www.eso.org/sci/facilities/eelt/owl/Blue_Book/9_Telescope_structure_and_kinematics.pdf

as  examples but there others if you google, sounds logical though

not saying everything is a waste, just thinking. I've paid for new bearings anyway so will replace them and call it an improvement (they may be abec 7 but they are stiffer than my ws2 lubed up old bearings, I may leave them alone)

[philj]

Always leave a bit of space. Overgreasing can cause problems. With high speed applications it is very important to avoid overgreasing but with the speeds we operate at its not so much of a problem but is not advisable.

[Zakalwe]

On 27/05/2020 at 00:23, Mikyg said:

Yes i removed the dust inserts, cleaned and regreased but i’m getting so many different views on this, some saying pack hard and some saying too much lol

Why would you think that the manufacturer knows less than us? its a sealed bearing, so it will be pre-greased with the correct amount.

Bear in mind that the bearing was made to run a lot faster than a mount axis too. 1 revolution per day is hardly going to stress a bearing meant for hundreds of RPM.

[Starflyer]

The grease will cause a lot more friction, not too much of a problem when tracking, however it may cause sticktion issues when guiding. The other problem overgreasing causes is that you'll really struggle to balance your mount with all that friction.

Edited June 4, 2020 by Starflyer