PM-45M Spindle Seals Replacement

GA Gyro · Dec 2, 2014

mksj said:
These are pretty light duty milling machines, but at the end of the day, they may benefit from a mainstream oil designed for this specific application. The most common is the Mobil DTE series circulating oil or their stabilized hydraulic oil. In a mill gearhead, either the Heavy-Medium (ISO 65.1, SAE 20 or gear Oil SAE 80) or Heavy (ISO 95.1, SAE 30 or gear oil SAE 85) are probably the most appropriate. Note that there are different ISO/SAE depending on the application, see chart. Enco carries these Mobil oils in 1 Gallon containers, when on sale with free UPS shipping, you are looking at $25 per container delivered. I would follow the manufactures recommendation on the ISO grade to use, it may vary somewhat if depending on your climate temperature and speeds you commonly use.

My BF-30 specifies ISO 100, but with a 3000 RPM top end, you can run into a lot of gear train drag from the oil with the high viscosity. The standard Rong Fu gearhead mills that I have seen use ISO 68 (SAE gear oil of ~80). I ended up with a synthetic 75-90W gear oil, so starts out a bit thinner, but holds it viscosity a bit better when it gets hot. I use an oil specific to gear drives, not car differentials. I do not know if it presents an issue, but most auto store gear oils are designed for differentials, so they have different additives and properties, especially those used for limited slip. Car engine oils are not recommended as gear oils because of the detergent used.

Lathe headstock and gearbox/carriage apron gearbox may be a bit different, Grizzly and many small-medium lathe manufactures often recommend an ISO ~32 oil for the headstock (DTE24 stabilized hydraulic oil ISO 32, SAE 10; or their DTE Light), and an ISO ~68 for the the gearbox/carriage apron gearbox. Lathes tend to have larger headstock gears then mills, using a higher ISO oil then recommended would cause significantly more frictional drag as the RPM is increased. So Mobil oil DTE24 or DTE light (ISO 32), and DTE26 or DTE heavy/medium (ISO 68). The Shell oil equivalents would be the Tellus 32 and 68 (see cross reference chart).

THX! Appreciate the information and charts.

Reading the lower (band comparison) chart... brings up a different question on lubricants for machine tools:

What is the difference between gear oil and way oil?
I realize one goes in the gearbox, the other is spread on the ways and other surfaces both for lubrication and to protect against rust.
I am curious as to the different make up of the oil, and lubricating qualities.

THX

mksj · Dec 2, 2014

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ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w

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oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

ontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w

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ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]-->[FONT=&amp]Lots of discussion postings, and many opinions. The type of oils to be used in mills and lathes is a controversial issue, and a lot of unsupported assumptions have been posted. Given that the manufacturer's recommended oil is readily available and reasonably priced, saving a few $ on an alternative may not be a good alternative in the long run. It is not that another oil with the same ISO or SAE rating won't work, but how long it will work.
http://www.practicalmachinist.com/vb/antique-machinery-history/can-i-use-gear-oil-headstock-197400/
http://bbs.homeshopmachinist.net/threads/35196-Alternative-to-way-oil

"Way oil is non-detergent oil with tackifiers added to make the oil cling to the ways, without increasing the viscosity of the oil. The purpose of way oil is to create a hydrostatic bearing surface, where the ways glide on a very thin film of oil. Motor oil does not have these tackifiers, so it just drips off the ways. In fact, you can look at the product development of some of the modern way oils, where the manufacturer has reduces the Peritack (the tackifiers), and the way oil gets runny, doesn't cling as well, and you get a lot more stick slip. This is not theoretical -- I've experienced this first hand, and I ran some experiments comparing the clingyness of the various common way oils on Practical Machinist."

Information posted by Mobil and manufacture's recommendations, both the support use of Mobil DTE "hydraulic oil" or DTE "gear oil" (or equivalent in the chart provided) for geared headstocks in lathes and mills. In general, motor oil and limited slip differential gear oil GL-5 are probably not a good choice for your lathe or mill over the long hall. Limited slip gear and probably manual transmission gear oils are actually less slippery then standard gear oil. Per Red line Oils "75W90 GL-5 gear oil is designed for transmission and trans-axles. It is specifically designed to slow synchros for easier shifting across a broad range of temperatures. It also contains extreme pressure additives but lacks friction modifiers to balance slipperiness. In addition, it has improved copper corrosion protection to prolong synchro life. Appropriate coefficient of friction for most manual transmission synchronizers (other's synthetic gear oils are often too slippery for proper synchro engagement). Excellent gear and synchro protection, balanced slipperiness for easier shifting in cold climates". Most lubricants for manual gearboxes and differentials are hypoid gear oils. These contain extreme pressure (EP) additives and antiwear additives to cope with the sliding action of hypoid bevel gears. EP additives which contain phosphorous/sulfurous compounds are corrosive to yellow metals such as the copper and/or brass used in bushings and synchronizers; the GL-1 class of gear oils does not contain any EP additives and thus finds use in applications which contain parts made of yellow metals.

Using too high a viscosity oil in a lathe or mill headstock will lead to increased heat, and a quicker demise of the bearings and gears. Multi-grade oils are not used/needed in these gearheads, most likely because operating temperature extremes are much less and the flow/mechanical properties required are different.[/FONT]

GA Gyro · Dec 2, 2014

THX, appreciate the explanation.

Was not thinking to substitute... just curious as to the details.

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PM-45M Spindle Seals Replacement

GA Gyro

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mksj

Active User

GA Gyro

H-M Supporter - Gold Member