|
|
Post by Callum Darraugh on Apr 23, 2014 15:13:25 GMT
Hi all, I was just wondering what peoples views were on oil vs grease on motion parts. Currently, the little and big ends on my Thomas II are oil but I am thinking about changing them to grease for a couple of reasons. The main reason is that the front big end is so awkward to get to when oiling up as you have to move the loco accordingly to get it in view, so if grease, I'd only have to do it once a day. This also comes to the other point - it would reduce the turn round time. When running to a timetable this is a big help! What are peoples views? I have added a poll above to get a general idea.  Cheers Callum |
|
|
|
Post by Roger on Apr 23, 2014 15:47:31 GMT
Just from a theoretical point of view, I wouldn't think you could use grease successfully because even with Oil, it's currently going to be boundary lubrication, and that's surely only going to be worse if you use grease. I think grease would quickly be squeezed out from the bearing surfaces and you'd be left without lubrication at all.
|
|
|
|
Post by Deleted on Apr 23, 2014 16:43:12 GMT
I wonder why products from the auto trade aren't used?.... I'm not referring to oil itself but some of the other advanced products available. When I assembled 4470 I covered all the bearings in engine assembly lube which to my mind would be a good product to use with the limited wear that a model would suffer when compared to an internal combustion engine, normal oiling is also given at intervals, another product that may be of use could be some of the slick 50 products... if they are good enough to run an engine for many hours with no oil in it whatsoever why not try it on our bearing journals? and then you have products such as 'engine restore' which is mixed with oil and actually repairs damaged journals by adding metal to any scores that may be present.
I can't see any harm from using auto products but stand to be corrected if it's been proven they are bad, I accept that steam oil is needed for cylinders but then it's designed for a specific job not faced in the auto trade.
Pete
|
|
|
|
Post by digger on Apr 23, 2014 19:31:13 GMT
You need a lubricant that is tenacious and not to be thrown off while the bearings are rotating, motor-cycle chain lubricant does just that, as I oil up the motion using a small syringe I am going to try some. to see how it performs.
Digger
|
|
|
|
Post by fostergp6nhp on Apr 23, 2014 20:01:59 GMT
Chainsaw chain oil is also anti fling and SAE 50.
|
|
bhk
Part of the e-furniture
Posts: 458 
|
Post by bhk on Apr 23, 2014 20:10:01 GMT
I could see no reason why grease could not work, but you need to have room in the bearing to retain grease ie grooves
|
|
|
|
Post by ejparrott on Apr 23, 2014 21:56:50 GMT
Grease bearings are rated for slower speeds than oil bearings, according to the list in the SKF book anyway
|
|
jma1009
Elder Statesman
Posts: 5,900
|
Post by jma1009 on Apr 23, 2014 22:14:26 GMT
hi callum,
speaking as someone who has a few locos with inside cylinders and valvegear i have never seen oil as a problem nor time taken to oil up. having the right type of oil can with a long length of thin wall 3/32" copper tube attached to the end helps considerably. i can oil round at the station and also refill the tender with water in the time it takes for one load of passengers to get off and another load get on. the small ends and slidebars need far more regular oiling than the big ends IMHO. generous oil reservoirs help of course but sadly this is often lacking.
cheers,
julian
|
|
|
|
Post by Rex Hanman on Apr 24, 2014 7:27:37 GMT
Cr*p sticks to grease and stays in the bearing. Frequent oiling flushes it out. I would prefer oil. |
|
|
|
Post by Deleted on Apr 24, 2014 12:05:55 GMT
Grease + grit = grinding paste !! .............PS}--- How does this "Poll" thingy work then ??
|
|
uuu
Elder Statesman
your message here...
Posts: 2,807
|
Post by uuu on Apr 24, 2014 16:28:05 GMT
You go to the top of the thread and click on the line and it grows by one. you can't vote twice, I've tried.
Wilf
|
|
pault
Elder Statesman
Posts: 1,496
|
Post by pault on Apr 24, 2014 17:02:55 GMT
I suspect that we are all saying oil because that’s what we have always used, however there does seem to be pluses for grease lubrication. If you are using a grease gun then any dirt will be forced out when greasing round. This makes interesting reading. You could try to the tech department of someone like Hallett oils or even one of the big oil companies. Have a look at www.mobilindustrial.com/ind/english/files/tt-grease-lubricated-plain-bearings-and-application-system.pdfguess it depends if you are prepared to take the gamble Regards Paul |
|
|
|
Post by chris vine on Apr 25, 2014 11:32:13 GMT
There is a problem with squirting grease into a bearing (under pressure) and that is if the bearing is worn. EG on kingpins of mg midgets! The grease just comes out of the worn part without going to the tighter spots....
Chris.
|
|
|
|
Post by ejparrott on Apr 25, 2014 12:32:06 GMT
or Land Rover prop shafts...guess where I've been this morning....
|
|
pault
Elder Statesman
Posts: 1,496
|
Post by pault on Apr 25, 2014 13:01:36 GMT
There is a problem with squirting grease into a bearing (under pressure) and that is if the bearing is worn. EG on kingpins of mg midgets! The grease just comes out of the worn part without going to the tighter spots.... Chris. That’s the same with oil though it just runs out of excessive clearances. In fact you could argue grease could be better for bearings with excessive clearances as it won’t just run out, it has to be forced out. King pin and prop shaft bearings are problematical for lubrication due to limited angular movement, A rotating shaft in a bearing will always be a better bet lubrication wise. When I used to work in engine test cells we used to line the engine and dyno up with a laser system. We would then jack the dyno out of line by a calculated amount so that the prop shaft bearings were moving enough to keep the grease moving. Regards Paul |
|
shooter
Part of the e-furniture
If it 'aint broke....don't fix it!
Posts: 252
|
Post by shooter on Apr 25, 2014 17:24:34 GMT
My twopennoth, look at the poll. Says it all, I think.
Cheers for now Steve.
|
|
|
|
Post by Callum Darraugh on Apr 25, 2014 17:41:45 GMT
Thanks for your replies chaps. It seems that nobody is keen on the idea of grease! On our railway at Brookside, we have 5 Exmoor locomotives (www.brooksideminiaturerailway.co.uk and click on locomotives link for those who don't know what they are) and they are grease on the big and little ends and we have never had a problem in the 14 years that we've had them. My loco is quite a chunky, industrial machine so I think I could possibly get away with fitting roller bearings into the motion..? Just for an idea of size, I've attached a picture below. (Please ignore the three stooges stood behind!)  Kind regards Callum |
|
|
|
Post by Deleted on Apr 25, 2014 17:43:56 GMT
|
|
bhk
Part of the e-furniture
Posts: 458
|
Post by bhk on Apr 25, 2014 17:54:53 GMT
This is a mainly British site, ask in chaski and the preference would be difference I suspect.
Always is more than 1 way to skin a cat.
Grease can and will work just as good as oil and in fact I think better if the bearing is designed for it. There has been a magnitude of literature wrote on this subject in various books and papers which are worth reading if you really want to make an informed choice and the correct design changes.
|
|
|
|
Post by Deleted on Apr 25, 2014 18:30:01 GMT
This is a mainly British site, ask in chaski and the preference would be difference I suspect. Always is more than 1 way to skin a cat. Grease can and will work just as good as oil and in fact I think better if the bearing is designed for it. There has been a magnitude of literature wrote on this subject in various books and papers which are worth reading if you really want to make an informed choice and the correct design changes. ---------------- try this for more info}------ www.chaski.com/ ---------- |
|
