Grease and Lubrication

[phil67]

Right then people


As winter is nearly here, its time to do some maintenance on my helis with new thrust bearings etc, so was wonder what you recommend for greasing up the bearings now as the last pot lasted many years and things have more than likely progressed.


So what do use?


Cheers


Phil

[GIXERMAN]

KY jelly, apparently it gets in anything!

[GIXERMAN]

just normally use the factory thrust grease and gear lubes, unless something special required then maybe the teflon gear comes out.

[dw45]

Think I'll stick with the KY.

[Cagey]

Coming from an aircraft engineering background I'd be very interested to know how you'd manage to get grease into a sealed bearing without a miniature pressure lubrication set up ? Any high speed grease would do the job, even frequent lubing every 4/5 flights with a light machine oil such as sewing machine stuff would do. Always remembering that oil insertion tends to wash out any existing grease.
But if you're going to use new bearings as you say, then they come pre packed with the correct grease anyway, so no need for all the above eh ?

[Peteski]

I just use Tri-FLow synthetic grease on open thrust bearings. I don't touch any of the sealed bearings as they have grease packed in anyway. As above if you try to oil sealed bearings you end up washing out the grease and then you have to keep on oiling them regularly.

[electricsceadu]

am i being stupid??????????????
but how can oil wash the grease out of sealed bearing?
as the seal should stop the oil entering the bearing in the first place

[10x]

The bearings we use on helicopters are metal shielded bearings, These bearings are not 100% sealed like the rubber shielded ones. But the rubber shielded bearings can not spin at the speed that we need because of friction...

[electricsceadu]

i was waiting for someone to state that we use shieled bearing not sealed bearing
as they are so different

and to re-lubricate a sealed or shielded bearing just pop the one seal/shield off (take care not to damage it)
re-pack with grease and refit the seal/shield
they may pass some gease out as the seal may not be as good as before on the shield/seal

[phil67]

Coming from an aircraft engineering background I'd be very interested to know how you'd manage to get grease into a sealed bearing without a miniature pressure lubrication set up ? Any high speed grease would do the job, even frequent lubing every 4/5 flights with a light machine oil such as sewing machine stuff would do. Always remembering that oil insertion tends to wash out any existing grease.
But if you're going to use new bearings as you say, then they come pre packed with the correct grease anyway, so no need for all the above eh ?

Most of the bearings are sealed like you say, but the thrust bearings are open and need to be placed the correct way, as the last pot of grease I brought was several years ago, and most things get better or so the manufacturers tell us matey

[phil67]

i was waiting for someone to state that we use shieled bearing not sealed bearing
as they are so different

and to re-lubricate a sealed or shielded bearing just pop the one seal/shield off (take care not to damage it)
re-pack with grease and refit the seal/shield
they may pass some gease out as the seal may not be as good as before on the shield/seal

Any recommendations of the grease you use matey

[Cagey]

Align Trex sell this stuff.Super Lube Synthetic Grease with PTFE - 12g Tube / Locking & grease / Tools & Supplies Model Helicopters But I've used the one way bearing grease that comes with Trex kits and up to now, no problems.
Also as electricsceadu says you can take the shield off for the purpose, if you're very careful to not lose the retaining clip ring.
As for oil washing the grease out, it's because it dilutes the remaining grease to such a thin viscosity that centrifugal force does so. All too fiddly, easier to swap the bearings out IMO.

[Peteski]

As for oil washing the grease out, it's because it dilutes the remaining grease to such a thin viscosity that centrifugal force does so. All too fiddly, easier to swap the bearings out IMO.

This ^

I've never felt the need to remove bearing shields to re-grease them. At that point I'm going to replace the whole bearing. The point is that if you do decide to oil them instead of using grease as some people insist on doing, then you just make more work for yourself as the oil thins the original grease and you soon end up with a dry bearing if you don't keep replacing the oil on a very regular basis. That's the whole point of grease vs oil lubrication. Open thrust bearings obviously need greasing occasionally.

[electricsceadu]

i use tri-flow grease on open bearings
shielded bearing i just replace them

[Mike Sanders]

I use Tri-flow grease on thrust bearings. On other bearings I find that the grease packed in them causes a bit of drag so I wash it out with white spirit then I oil the bearing with a good quality synthetic oil (Faller usually). This enables the bearing to run much more freely. The lack of friction gives me long run times. I have to oil them every 6 flights but that is no hardship.
I have never had a bearing fail except as a result of a hard impact.