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Any benefit to EP grease in a milling machine?

thebencarter

Aluminum
Joined
Aug 23, 2017
I am getting ready to regrease the tapered roller spindle bearings my Van Norman 1R3, and based on the "California Roll Grease for Van Norman" thread, I was set to order Chevron SRI 2. Then I noted they have a fully compatible EP grease (Black Pearl EP). Is there any benefit to EP grease in this application? Any downsides? There are oil seals between the cutterhead gears and the bearings, preventing grease migration, and I don't think there are any yellow metals in the cutterhead to begin with.

Thanks,
Ben
 
I'll be interested to learn/ hear of whatever you chose to go with for the grease, as well as any things "learned along the way" in your disassembly and reassembly of the spindle bearings. The grease in the spindle bearings in my recently-acquired 1R3 is of unknown vintage and could well be original to the machine, so at some point I want to regrease. Thanks
 
If there are no copper alloys in contact with the grease it could work but the EP additive probably is of no value with taper roller bearings.

 
I ended up ordering the regular Chevron SRI 2.

kd1yt,

I am in the same boat as you. The grease I could see by taking off the top/rear bearing cap was in 'OK' shape - some of it was crusty after "sitting on the sidelines" having long since made its way out of the bearing, but the relatively little grease left in the bearing itself seemed OK. It was tan colored grease.

I have not decided if I am going to pull the spindle or not. You can more or less flush grease out of the top/rear bearing by taking off the bearing cap, running the spindle at low speed and pumping grease into the zerk, wiping off the excess as it comes out the top. The Chevron grease is green in color so it's easy to tell your progress by the color of the grease coming out. The problem is the lower/front bearing as you cannot take off the bearing cap without pulling the spindle. For the short term I pumped some new grease in there - I just estimated by how much it took to see the new grease getting to the top/rear bearing. I'd really like to have both bearings running with fresh clean grease but I also don't want to risk ruining anything by pulling the spindle.

Ben
 
I'll be interested to learn/ hear of whatever you chose to go with for the grease, as well as any things "learned along the way" in your disassembly and reassembly of the spindle bearings. The grease in the spindle bearings in my recently-acquired 1R3 is of unknown vintage and could well be original to the machine, so at some point I want to regrease. Thanks

I believe I may be of some minor help here : the EP bitS of the grease start working once a certain temp has been reached and/or there is insufficient or no oil film. In other words 3 situation. To select the right grease you need to decide how long you want the bearings to last and come up with some average figure for the speed. The EP fractions are soluble or solid. In general you do not want solid fractions for precision bearings. The soluble fractions will have no effect ( now that lead naphtanate is out ) until the temps are high - much higher than a spindle in normal use will ever see. But, a spindle sees repeated shock load. To cut it short, any auto bearing grease with very little or preferably no solids will work wonderfully. You want an oil viscosity of around 150cSt - this gives the shock load protection and for low speed ( under 1000 rpm ) you can go up to 220cSt ambient. This drops 4-6 times when the spindle gets hot. I stay clear of "fine" aircraft/heli greases. They have too thin oils in the region of 18cSt. I get very good, verified results with Chevron Multifak EP which is a soft 220cSt grease but I am sure there are many other as good or better. The grease you've chosen has a cSt of 116 ( 40C) and might be on the thin side for low rpm with repeated shock loads. It's a polyurea which means it is targeted at electric motors and you'll need to scrupulously clean the old one.
 
Alex,

Thanks for the additional information - I know next to nothing about different greases and their applications, so it is helpful.

The 1R3 has a 2000 RPM spindle and the 1RQ3 has a 3600RPM spindle - certainly nothing like CNC machines these days, but not low speed like a big hulking horizontal of yore. Van Norman specified the same grease for both machines, and it is the VN part number 19249 which was cross-referenced to Chevron SRI 2 in this thread: http://www.practicalmachinist.com/v...rnia-roll-grease-van-norman-89257/#post197927

Based on your warning to clean out the old grease thoroughly, that would imply an incompatibility. Can you elaborate? I was hoping to avoid a mandatory spindle pull to clean the bearings by choosing a compatible grease.

Thanks,
Ben
 
Alex,

Thanks for the additional information - I know next to nothing about different greases and their applications, so it is helpful.

The 1R3 has a 2000 RPM spindle and the 1RQ3 has a 3600RPM spindle - certainly nothing like CNC machines these days, but not low speed like a big hulking horizontal of yore. Van Norman specified the same grease for both machines, and it is the VN part number 19249 which was cross-referenced to Chevron SRI 2 in this thread: http://www.practicalmachinist.com/v...rnia-roll-grease-van-norman-89257/#post197927

Based on your warning to clean out the old grease thoroughly, that would imply an incompatibility. Can you elaborate? I was hoping to avoid a mandatory spindle pull to clean the bearings by choosing a compatible grease.

Thanks,
Ben

Ben, you're going to use a polyurea grease which I think it's the grease most incompatible with ALL the other greases. It's compatible only with itself as far as I remember. Even smallish remnants of another ( incomp. ) grease may cause hardening, softening or oil bleeding. Not worth taking a chance. Then, there is something else : small cakes of old grease - hardened bits tend to contain steel particles which acted initially as some sort of catalyst. If they're not cleaned thoroughly they will release them and you don't want them back. :)

I tend to be very suspicious on "Company recommends..." because often there is no actual investigation behind the recommendation. The best of them often change their mind or simply and intentionally recommend the wrong thing. For example, the recommended grease for MAHO1000 ( a BIG machine ) is ....NBU15 from Kluber. That's a joke but one which made money for MAHO and Kluber. If your spindles live more or less around 1500rpm, then the grease you have chosen is excellent. If they live around 3-600 rpm with large face mills etc then I would go for a thicker oil cSt 220.

I clean bearings with paint thinners followed by acetone. You may see an alarming amount of scoring, pitting etc but in most cases it's absolutely inconsequential. With new grease there is a distinct tendency to set the bearings too lose - I'd err the other way. Reason is the oil in the old grease has been churned a lot and has become thin while the thickener has thickened. The thickness of the thickener has little to do with anything within reason.
 
Alex,

As before, thank you for the information. I figured I was safe choosing a cross-referenced "replacement" grease, but I was considering pulling the spindle anyway; the info in this thread pushed me off the fence. Once I get a bit of time I'll pull out the spindle and clean out the bearings.

Thanks,
Ben
 
Alex,

As before, thank you for the information. I figured I was safe choosing a cross-referenced "replacement" grease, but I was considering pulling the spindle anyway; the info in this thread pushed me off the fence. Once I get a bit of time I'll pull out the spindle and clean out the bearings.

Thanks,
Ben

Glad to have been of some assistance.

I suggest you note down the run out of the bearings on the outside of the spindle nose and mark the position of the inner races on the shaft. This might help with some tweaking later particularly if the spindle ran loose and there was some wobble.
 
The best of them often change their mind or simply and intentionally recommend the wrong thing. For example, the recommended grease for MAHO1000 ( a BIG machine ) is ....NBU15 from Kluber. That's a joke but one which made money for MAHO and Kluber.

NBU15 seems to be recommended for everything. What would be the correct grease for the Maho 1000 spindle? And where is NBU15 appropriate?
 
NBU15 seems to be recommended for everything. What would be the correct grease for the Maho 1000 spindle? And where is NBU15 appropriate?

I would use a good OEM wheel bearing grease - say, what Mercedes Benz or WV use. They DO spend time and money on testing and suppliers know what will happen to them if they miss. The bearing of a wheel with disk brake takes the sort of punishment a spindle never sees. From -30C to almost red hot. And they seem to last pretty well. :) Over 200k miles in my present car and the bearings ( like in most modern cars ) are preloaded angular contacts. My go to grease is Multifak EP2 but I am sure with some digging one can find better. Multifak is a softish, buttery grease which works from the get go.

I use Kluber in small HF spindle bearings and it works fine. But I wouldn't put it past fine. Both SKF and ********* have alternatives which are a fraction of the price and seem better. Notice that Kluber has a ton of greases for which NO meaningful data is ever available. Like a 4 ball or Timken test.
 
Glad to have been of some assistance.

I suggest you note down the run out of the bearings on the outside of the spindle nose and mark the position of the inner races on the shaft. This might help with some tweaking later particularly if the spindle ran loose and there was some wobble.

Alex,

I checked just now and the spindle has about 3-4 thou axial end play, measured as follows: set the spindle horizontal, tap the front of the spindle with a block of wood and a small sledge, zero a tenths dial indicator, tap the back of the spindle. So that's set a bit loose right now.

The spindle has basically zero radial runout, I only have a 5 tenths test indicator but it barely moves; I would estimate 1-2 tenths runout. I measured this on the taper. Any reason you say to measure it on the outside of the spindle nose?

A question about what grease to use when reassembling. The spindle can run from 55-2000RPM (and even lower as it's on a VFD), and I have already used 4" and 5" face mills running between 310RPM (cast iron) and 1200RPM (aluminum). I'll be running end mills in aluminum and needing every bit of speed it has, and I also will be running big face mills and HSS horizontal slab mills at low RPMs. I'd really like to be able to use the entire range without feeling like performance is compromised or I'm hurting the machine. The cSt 220 grease you mentioned may be too thick to run at high speed and perhaps the Chevron grease I'm running now won't protect well enough at low RPM. Any further thoughts on this?

Thanks,
Ben
 
As a point of reference, plenty of Deckel and Aciera Euro-mills use roller bearings in their 40-taper spindles, and the speeds span ~30 RPM to ~3000 RPM. The original OEM grease was Kluber Isoflex Super Tel. I have mine currently greased with Kluber NBU-15. I have no issues or worries at either end of the speed range, as long as I don't over-pack the bearings with grease. A little dab on each roller is all that is needed. MBU-15 base oil is fairly thin, around ISO 21.
 
Alex,

1. I checked just now and the spindle has about 3-4 thou axial end play, measured as follows: set the spindle horizontal, tap the front of the spindle with a block of wood and a small sledge, zero a tenths dial indicator, tap the back of the spindle. So that's set a bit loose right now.

2. The spindle has basically zero radial runout, I only have a 5 tenths test indicator but it barely moves; I would estimate 1-2 tenths runout. I measured this on the taper. Any reason you say to measure it on the outside of the spindle nose?

3. A question about what grease to use when reassembling. The spindle can run from 55-2000RPM (and even lower as it's on a VFD), and I have already used 4" and 5" face mills running between 310RPM (cast iron) and 1200RPM (aluminum). I'll be running end mills in aluminum and needing every bit of speed it has, and I also will be running big face mills and HSS horizontal slab mills at low RPMs. I'd really like to be able to use the entire range without feeling like performance is compromised or I'm hurting the machine. The cSt 220 grease you mentioned may be too thick to run at high speed and perhaps the Chevron grease I'm running now won't protect well enough at low RPM. Any further thoughts on this?

Thanks,
Ben

1. That's around 75-100 microns - that's horribly loose. But I don't think it caused any problem. Maho on 700/1000 says 5 microns for a Gamet tapered roller set, one at each end. Others, SAME bearings want from zero to some degree of preload. All lathes, very similar bearings, 68cSt oil,need pretty high preload. Gawd knows.... :)

2. The unloaded runout is usually very low, often zero because the grease/oil inside averages everything. The real runout would be with the spindle bearings washed and bone dry. The reason to measure outside is because the inside taper is often damaged and as a rule less concentric with the bearings than the outside of the nose. Unless the spindle was "ground in place". A treacherous endeavor... Measure in the middle, between the tabs. Next to the tabs is distorted both in and out.

3. I think your first choice is 100%. Anything over 68cSt ( lathe bearings which are heavily pushed do fine in that ) is going to be OK. 220 might be a bit much though I am experimenting with one now and I can't get the spindle to complain. I use 220 in my ( two ) mills as I run everything at 300rpm - my middle name. I found a very impressive grease with a Timken rating twice anything else, but it's a 250cSt. Might be a bit much.
 
1.As a point of reference, plenty of Deckel and Aciera Euro-mills use roller bearings in their 40-taper spindles, and the speeds span ~30 RPM to ~3000 RPM. The original OEM grease was Kluber Isoflex Super Tel. I have mine currently greased with Kluber NBU-15.

2.I have no issues or worries at either end of the speed range, as long as I don't over-pack the bearings with grease.

3.A little dab on each roller is all that is needed. MBU-15 base oil is fairly thin, around ISO 21.

1. The original OEM grease was there to support another German business - it's what they do over there. It was rubbish in those specific applications. I've seen A LOT of spindle insides and on Deckel/Maho/Aciers you almost always see the front bearing outer cone/race blued. On Maho 600/700/800/1000 the outer cone is machined in the spindle housing ( there are exceptions ) and once buggered, it's a new spindle. If you re-lap/reground it slightly the discoloration will not re-appear with the most ordinary wheel bearing grease. Notice that electric motors run 3600 rpm for decades with that sort of grease at much higher temps and with much larger deep groove (!) bearing diameters. Depending on what you do with it, your spindle should be fine - The Airbus planes land on Nyco GN10/14/22/24 which is thinner than NBU15. But they don't drive on it... :)

2. There is nothing wrong with overpacking the bearings with grease provided the grease has some place to go and you warm up the machine for a couple of minutes before work. There is a lot wrong with having very little grease ( a dab..) in the bearings. Far less heat transfer and far quicker chemical degradation from metal contact - like 10 times quicker. Less grease to be churned, much quicker thinning of the oil. etc. High speed, different concerns altogether.

3. Carry on, it made money for me. :) NBU15 was given over the years with various viscosities. Memory serving, started around 14. I could never find any relevant data about it though in HF spindles performs well. But so do the Nyco/SKF/********* greases for a less than a fraction of the price. Bottom line is that if spindle gets hot and you can't stop it to cool down you need grease to carry away the heat. You have a lot of shock load, you need cSt's for protection.
 
1. I've seen A LOT of spindle insides and on Deckel/Maho/Aciers you almost always see the front bearing outer cone/race blued.

That's news to me, and probably AlfaGTA and DeckelDoctor, too. I have not seen the issue with Deckel or Aciera spindles.

2. There is nothing wrong with overpacking the bearings with grease.

Okaayyy. Sure. SKF etc., would beg to differ.
 
1. I've seen A LOT of spindle insides and on Deckel/Maho/Aciers you almost always see the front bearing outer cone/race blued.

That's news to me, and probably AlfaGTA and DeckelDoctor, too. I have not seen the issue with Deckel or Aciera spindles.

2. There is nothing wrong with overpacking the bearings with grease.

Okaayyy. Sure. SKF etc., would beg to differ.

1. I believe you but then, how many spindles have you seen opened ? Three ?? The overheating of the lower bearing on the vertical spindle was a very common problem with those machines in production. A homeshop machinist might never see this problem. I've no idea who are AlfaGta and DeckelDoctor but you shouldn't presume what they've seen or what they'll say. I am quite curious as to their experiences as Deckel and Maho changed the spindle grease a few times and I would like some info on that.

2. On low speed spindles like Deckel or Maho there is ample space inside the spindle for the grease to move. One fills the bearing with grease as well as possible, adds something over and under the bearing and then runs in the spindle at low rpm to distribute the grease. A lot of grease will just be evacuated. To my eye, aprox 1/2. Next time I'll service a spindle I'll measure. The SKF recommendations are generic i.e. the bearing may run up to nominal speed. That'd be around 4 times the rpm on a Deckel/Maho. And SKF uses way more grease than "a dab" inside their bearings with RS1 shields. That tells us something. This is a field where one shouldn't rely blindly on manufacturer's recoms - manuf is known to have made big cock ups with spindles. :) The factory my dad worked for before retiring had a fair amount of M800s and the manner the Maho people serviced the spindles was nothing like the BS in the manual. But then, a mistake would've been very costly and swiftly recovered - that wasn't a plant tolerant towards suppliers and packed a big punch.
 
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