Greasing motor bearings

[Gavlar]

hi all,

I'm aware there are two basic types of grease nipple, the old sort which just relies on pressure contact and the new sort which have some sort of snap-fit to the grease gun.

My 60s vintage Gryphon motor on the Coronet lathe should I guess have the old sort, but before I get the wrong type of gun, please can somebody confirm this is correct?
Terrible photo, sorry:


I thought old ones had curved tops, but these are flat with a waisted shank, so I'm wondering if they're 'new type'.

thanks
Gavin

 

[Duncan A]

That looks like a push-on type but it doesn't seem to have a valve ball in it. These are basically spring-loaded one way valves which prevent ingress of dirt and loss of grease - a bit like a ball-point pen. Unscrew the grease nipple and take it to Halfords to be sure - if they're open, that is.
Duncan

 

[guineafowl21]

A chainsaw-type grease gun will work with almost any grease nipple. Worth a try.

 

[--Tom--]

They’re the type I have on my bandsaw and work with a sealey grease gun.

never sure how much grease bearings need though?

 

[NetBlindPaul]

Historically the largest root cause of motor bearing failure was over lubrication.
Unless under extreme loads or environmental conditions an electric motor bearing needs little lubricant unless it has been neglected.
On a diy machine, if the grease is getting to the bearing perhaps one shot per year.
The nipple in the picture is of the “standard”, design known as a “hydraulic”, the alternative is a slide on type which is totally different.
The profile of the hydraulic type has changed slightly over the years, but every one I have come across will work with the “normal” “hydraulic” grease gun which fits on in line with the nipple.
The slide on type has the connection slid on from the side.
The nipple in the picture does appear to be faulty as has been suggested previously in the thread.
They are easily obtainable and replaced, but you just need to get hold of one that has the correct thread.

 

[NetBlindPaul]

Pdf in the link for example data from one of my suppliers when I was doing wood machinery service work.
Grease nipples

 

[pgrbff]

Historically the largest root cause of motor bearing failure was over lubrication.
Unless under extreme loads or environmental conditions an electric motor bearing needs little lubricant unless it has been neglected.
On a diy machine, if the grease is getting to the bearing perhaps one shot per year.
The nipple in the picture is of the “standard”, design known as a “hydraulic”, the alternative is a slide on type which is totally different.
The profile of the hydraulic type has changed slightly over the years, but every one I have come across will work with the “normal” “hydraulic” grease gun which fits on in line with the nipple.
The slide on type has the connection slid on from the side.
The nipple in the picture does appear to be faulty as has been suggested previously in the thread.
They are easily obtainable and replaced, but you just need to get hold of one that has the correct thread.

I have just bought a bandsaw with what I believe are called Kauffer cups? I hope I'm making the right decision but I have been told it would be better to replace the 6205 bearings with sealed and forget the grease.

 

[minilathe22]

The modern approach is usually to replace bearings with sealed ones, which prevents the grease applied at the factory escaping and also prevents excessive grease being added, which can cause overheating and then all the grease gets burnt off!

However I believe if you top up the bearings very occasionally with grease they will last a long time.

 

[guineafowl21]

Here’s an overgreased motor bearing for you:

 

[pgrbff]

If open bearings are so bad, why aren't manufacturers using sealed? It can't just be cost?

 

[minilathe22]

Sealed bearings are a newer design, I think older machines assumed a knowledgeable owner would regular add the correct amount of grease. Modern bearings are designed without any maintenance in mind.

A well kept open bearing will last longer than a sealed one, but it's a lot less hassle with sealed bearings!

 

[Gavlar]

thanks all...much faffing about trying to find the right spanner, but I've got them off and the ball valves and springs are indeed gone from both nipples. What grease is there is pretty solid so I need to get some inside. New ones needed, so actually it doesn't matter whether these are old or new, they're junk!

One of them is on a long stalk, and I need to find the right thread.

 

[Cabinetman]

You probably know, I reckon that stalk unscrews from that nipple, sorry just in case.

 

[Gavlar]

I thought it might too, and it does!...trouble is I then need a nipple with an internal thread and I don't see them available anywhere. A M-F thread adaptor would work, but would make the assembly too long. We have a hydraulics supplier locally and I'll pay them a visit to see what options I have.