sprocket nose grease

[wde_1978]

I occasionally soak the bar sprocket with bar oil and just let it sit like that.

The clutch drum needle bearing gets a few drops of bar oil when I take the drum off to clean it.

 

[MustangMike]

Never greased them, never had them fail, well, not completely. Had sprockets lock up on me couple of times when they were buried in wood and the wood jammed them. I just pull the chain, spray with WD-40 and use a hammer & screw driver to get them to spin. Still using them.

It has only happened to me when the sprocket is buried and I'm working the dogs too hard.

 

[Deleted member 83629]

thanks for the help guys.

 

[Little Al]

That's because they are the best..........

More that they want you to spend more £$'s on quicker worn out replacements How can metal bearing on metal with no lubrication be good, it goes against all engineering best practices.

 

[Ferguson system]

The bearings are lubricated by the chain oil.

 

[atv1965]

I think one of the most common complaints on this forum is how saws don't oil the bar/chain enough, especially Stihl's...

 

[GPX433Todd]

More that they want you to spend more £$'s on quicker worn out replacements How can metal bearing on metal with no lubrication be good, it goes against all engineering best practices.

Having different hardnesses in the two metals that are touching is the key. Even the slightest difference is all that is needed. Dissimilar materials is also an important factor. When using this practice, little or no lube is needed.

 

[olyman]

The bearings are lubricated by the chain oil.

think about physics, before answering.....

 

[Little Al]

Having different hardnesses in the two metals that are touching is the key. Even the slightest difference is all that is needed. Dissimilar materials is also an important factor. When using this practice, little or no lube is needed.

Could you please enlighten me re you statement, during the time I worked on Mods on the SR71 Aircraft several working surfaces of dissimilar metal were originally assembled with a coating of some special metal coating to enable them to run without the use of a lube of any type, they reached failure point in a span of very short time The part with the coating was replaced with a bare titanium bearing surface & hardened steel on the other surface lubed at service intervals & to the best of my knowledge none needed replacement while the aircraft remained in service I'm not a metallurgist but after being involved in engineering in the aero industry for getting on for 50 years I know wear when I see it, & if I'm paying the bill I'd rather the surfaces are lubed. Another example that comes to mind is Marine stern gear on small boats Stainless shaft / white metal or bronze bush without lube is a short life span + excessive heat; I know some guys swear by none lue of bar tip sprockets but has any one logged the # of hours run to replacement Non lubed v Lubed. I service saws for a comercial Pro logging Company & when we used Stihl saws we didn't use Stihl bars due to not being able to lube the nose sprocket Each to his own I 'm just trying to get true facts of wear rate/hours between lube/non lube

 

[GPX433Todd]

Could you please enlighten me re you statement, during the time I worked on Mods on the SR71 Aircraft several working surfaces of dissimilar metal were originally assembled with a coating of some special metal coating to enable them to run without the use of a lube of any type, they reached failure point in a span of very short time The part with the coating was replaced with a bare titanium bearing surface & hardened steel on the other surface lubed at service intervals & to the best of my knowledge none needed replacement while the aircraft remained in service I'm not a metallurgist but after being involved in engineering in the aero industry for getting on for 50 years I know wear when I see it, & if I'm paying the bill I'd rather the surfaces are lubed. Another example that comes to mind is Marine stern gear on small boats Stainless shaft / white metal or bronze bush without lube is a short life span + excessive heat; I know some guys swear by none lue of bar tip sprockets but has any one logged the # of hours run to replacement Non lubed v Lubed. I service saws for a comercial Pro logging Company & when we used Stihl saws we didn't use Stihl bars due to not being able to lube the nose sprocket Each to his own I 'm just trying to get true facts of wear rate/hours between lube/non lube

Here's alot of info for you. If you finish it all and your brain isn't twisted all up, you'll have a good understanding of what I was saying. It's not a simple two or three sentence answer. Tool & Die maker by trade.
http://www.crucibleservice.com/eselector/general/generalpart1.html

 

[wde_1978]

The bearings are lubricated by the chain oil.

think about physics, before answering.....

The chain doesn't always spin!
Whenever the chain is still standing the oil can seep through to the sprocket bearings.

I agree with @Ferguson system 's post, the chain/bar oil is supposed to lube the sprocket.

 

[Philbert]

My FIL always said, that if you grease them from new you keep greasing them, if you have never greased them don't start. He does not grease his bearings and I have never seen his saw down because of a bad sprocket nose, bar wears out before that happens.

+1

Had another non drilled bar, I drilled it and greased it.

STIHL (and similar bars) have an inner disc between the inside face of the bar and the sprocket bearing. You have to drill through the bar and the thin inner disc without hitting the bearings (and try not to put drill filings into the sprocket bearings).

Stihl bars don't even have a hole for grease.

Neither do the new Oregon 'SpeedCut' bars.

How does the bar oil lube the tip when centrifugal force throws oil away from the bearing?

Really? have you ever touched a guide bar and not come away with your hands coated with oil? It goes everywhere!

Philbert

 

[7sleeper]

A few drops of engine oil after every cleaning is all my sprokets get. Works since decades.

7

 

[Idahonative]

I don't buy those specialized little grease guns and their expensive cartridges:
http://www.amazon.com/Oregon-Chain-Premium-Grease-110534/dp/B0002ZY216

I just use my general purpose grease gun which I have to have for tractors/trucks etc:
http://www.napaonline.com/Catalog/C...-Lincoln-Industrial/_/R-BK_7151142_0006381963

The only thing extra to buy is a needle nose adaptor which I have to have to grease the transfer case u-joint on my truck (fish eye zerk):
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151211_0361072904

Connect the needle nose adaptor to the grease gun and you have a cheap source of grease for your bar. I grease mine every time I fill the tank...a shot or two, until I can start to see grease. Does it need it? Probably not but it's quick, cheap, and that's the way I was taught...Oh, and I've never had bar issues.

 

[Philbert]

Those little grease guns are just handy to carry in the tool box.

Philbert

 

[olyman]

The chain doesn't always spin!
Whenever the chain is still standing the oil can seep through to the sprocket bearings.

I agree with @Ferguson system 's post, the chain/bar oil is supposed to lube the sprocket.

when you set a saw on the ground,,with the correct size bar,,is the nose of the bar,,up, or down??? and just how much oil,, does the pump put out, when its just idling?? and tell me,, you just idle your saw,to lube the nose bearing..............................................

 

[wde_1978]

when you set a saw on the ground,,with the correct size bar,,is the nose of the bar,,up, or down??? and just how much oil,, does the pump put out, when its just idling?? and tell me,, you just idle your saw,to lube the nose bearing..............................................

Some people I don't understand, and luckily for me I don't have to!

While idling a saw doesn't put out any oil, unless it is a really old saw that pumps oil whenever the engine is running - there are some saws like that to my understanding!
And I didn't say idling, I said still standing chain.

The oil that is caried by the drive links can seep onto and past the sprocket to the sprocket bearings once the chain stops moving.
And it doesn't matter whether the bars nose is pointing up or down as there are always several drive links engaging the sprocket and each is carrying oil.
And no, the oil doesn't get thrown of AT the bars tip, it gets partially flung off half way or 2/3 PAST the tip spraying slightly down from the bars tip, meaning that there is always a few drops of oil held by the drive links that are sitting on top of the sprocket!

How much oil is carried by the chain?
One full tank of oil on one full tank of fuel!
To clarify, that would be 420ml of oil to 750ml of fuel for a Dolmar PS-6400/7300/7900.
That is about 45 minutes of run time for a Dolmar PS-6400 with the pump choked down a bit, and about 30 minutes of run time on a Dolmar PS-7900 with the pump at its maximal flow - both saws stock!

Not trying to step on anyone's toes here, but if You don't see the logic to that then it is Your problem not mine!

This is my final post in this thread!
It is a sincere and good question by the OP and I hope he got his answers.

 

[lasmacgod]

I understand physics well enough. On that note, the argument that centrifugal force keeps bar oil from getting to the sprocket bearing is quite logical.

However . . . physics long held that a bumble bee should not be able to fly, and yet, just as the bumble bee does fly, bar oil always gets to the sprocket bearing on my bars, which I never grease whether there is a hole or not. Divine intervention? Maybe. All I know is I don't question it, not for one second.

 

[huskihl]

I always figured that if the bar groove is deeper than the drive links, the bar oil that settles off the links is getting down to the sprocket

 

[Big_Wood]

i don't grease them either. there was a while where i greased them while milling but i got an auxiliary oiler and realized it was just due to a lack of oil why i was going through tips. if a guy must grease though i would use a lithium grease as it will last the longest in between greasings.