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milling machine bearings

macsonboy

Aluminum
Joined
Dec 27, 2020
Location
Australia
hi all i am looking for advice on lube for new bearings. some history first .the milling machine is Italian made NOVAR. when i purchased it the machine did have noisy bearings so i changed the sludge (oil) and used auto trans fluid (ep oil- extreme pressure) and it has been good for a few years but still noisy , so i decided at last to fit new bearings. The bearings are in the gearbox and not the spindle. the bearings consist of double row ball type,, single row ball type and tapered roller. Now my main question is do i stick with the tranny oil or use 90w gear oil?? the oil pump in the gearbox is a paddle which spins and throws oil around but there is no pump of any sort. i like the idea of the lighter oil because it gets up higher quicker. hope someone may have an idea for me thank you in advance.( hope the photo helps)
 

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90W is too heavy. Transmission fluid may be too light. What is the manufacturer's recommendation? Most of the time that is something around 30 weight.
 
The gearbox in mine looks very similar to this. It also has no oil pump and relies on the gears flinging oil around to lube everything.

It uses Mobil DTE Heavy Medium circulating oil which is an ISO 68 oil which equates to a SAE 20 oil.
 
90W is too heavy. Transmission fluid may be too light. What is the manufacturer's recommendation? Most of the time that is something around 30 weight.
thanks for the reply,, no information tag on the machine , makes it hard. i am using the auto oil and see how it goes
 
The gearbox in mine looks very similar to this. It also has no oil pump and relies on the gears flinging oil around to lube everything.

It uses Mobil DTE Heavy Medium circulating oil which is an ISO 68 oil which equates to a SAE 20 oil.
thanks for answering ,,mine has no pump just a paddle that spins on the end of the lower shaft so i am sticking with the tranny oil.
 
90W is too heavy. Transmission fluid may be too light. What is the manufacturer's recommendation? Most of the time that is something around 30 weight.
latest update is the bearing supplier and the oil people are hunting up something closer to the 30 you mentioned cheers
 
How so? There are many high load/high speed gearsets running in atf. Nearly every auto and light truck on the road.
a transmission also has an oil pump to push it between bearings constantly under high pressure between 60-180psi. Any lack of oil pressure or loss of fluid eats up everything inside a modern transmission due to the oil being flung out under high loads and centrifugal force.
Thicker oil with tackifiers stick to surfaces protecting them better, plus bearing/bushing tolerances in a lathe are a bit more loose then a transmission which requres a thicker oil also.
 
Dexron 3 ATF is about an ISO VG 32, or a 15W SAE crank case oil, or a 75W SAE gear oil. Dexron 3 is not thick enough to make a AGMA 1 oil. Confused yet?
 
ATF is one of the worst possible lubes for non filtered machines. It has lots of additives to keep gunk suspended so it can be pumped to a filter.
With no filter and no pump it just keeps clouds of gunk floating to all moving surfaces. A proper oil for your machine would be non detergent so the gunk can settle to the bottom of the sump and stay down there until drained.
Bill D
 
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We were having problems with some large Poreba lathes in the mid 90s.
It was 100°+ summer temps.
These things were running hot.
One of the equipment builder came in and looked at it, then called some people about it.
He came back a few days and drained all oil.
Then put in some type of hydraulic fluid.
Machines still ran hot, but the oil flow window looked good.
During the winter when it got 20° at night , the lathes started quietly, and ran good.
I'm not saying it's your solution, but check around and find what is right.
These were 48" swing by 16 foot bed lathes.
We never would have thought hydraulic fluid was right
 
We were having problems with some large Poreba lathes in the mid 90s.
It was 100°+ summer temps.
These things were running hot.
One of the equipment builder came in and looked at it, then called some people about it.
He came back a few days and drained all oil.
Then put in some type of hydraulic fluid.
Machines still ran hot, but the oil flow window looked good.
During the winter when it got 20° at night , the lathes started quietly, and ran good.
I'm not saying it's your solution, but check around and find what is right.
These were 48" swing by 16 foot bed lathes.
We never would have thought hydraulic fluid was right
i think you may be half right ,, i spoke to an oil supplier and he said hydraulic oil may be what we need cheers
 
i think you may be half right ,, i spoke to an oil supplier and he said hydraulic oil may be what we need cheers
most lathes and similar will require an "AW68" oil or AW 46" which is a hydraulic oil, others like "Mobil DTE Heavy have other additives added to a AW 68 oil that have tackifiers to make it stick to bearings and not get flug off.
 








 
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