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10k Spindle refresh questions

PmGRacer

Aluminum
Joined
Dec 18, 2008
Location
Oakland Twp. Mi
Hello gentlemen. Over last few days I have torn down spindle of my 10k to replace the roller thrust bearing with a SKF 51107 roller thrust bearing. As you would guess a few unexpected items needing attention popped up![emoji33][emoji1]

First, the faces of the Bull gear and the Cone pulley looked like they got in a fight that everybody lost.
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I wasn't pleased with this blatant disregard for maintenance but all I could do is repair it. I chucked up the cone pulley and did a clearance cut up to the diameter of the damage.
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This gave me a "boss" to do a clean up pass on. The clearance between boss and cone face is only 0.005". Next I put the cone on a surface grinder and ground the face until it cleaned up.
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Next I rotated the cone every 45 degrees on the chuck leaving the wheel at zero to spark out the surface. I did 8 "clockings".
I then did the same to the Bull gear hub face.
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Once I cleaned it up I cleaned off a granite surface plate and started lapping the faces with 280,400,600 and 1200 grit paper.
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Both finished:
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I have only used spindle oil to lube the cone but I believe the face damage was already done when I got the lathe. Based on the research I've done in the forum, Roy Dean Grease isn't happening for me. Not sure if I'm going to use the Soy based lithium either. I am thinking of using Vactra Way lube often. I prefer to use oil over grease-quirky I know[emoji12]. Question here is should I make a relief in the cone face for oil to travel between the faces? Logic tells me I will be doing this repair again if I don't ensure proper lubrication often.


I did order new capillary oilers for the spindle. I am working on cleaning up the bearings, oil sling gutters and the oil wells. Is there any solvent that will cut the old oil build up off the bearings better than mineral spirits? This is the state of the bearings now:
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They don't look fantastic but I believe they are still good. The spindle had 0.001" play before I removed it and has always left a good finish on my work pieces. It looks like at one point the oil got hot and started to burn but the bearing surface looks ok. The burnt oil will come off with some work using min spirits on the blue shop towel. I do not want to use Scotch Brite or any other abrasive; just patience and solvent.

The spindle needs some polishing on the cone diameter. I want to make a brass/bronze lap and use lapping compound to bring surface back. I will post that if I make that happen.
Sorry for the long post gentlemen. I will post updates as I put it back together.


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That kind of mark on the pulley/bullgear, normally results from the bullgear not properly pressed onto the spindle. instead of the spindle pressing against the thrust bearing and the pulley floating freely, the bull gear is pressing against the pulley which presses against the thrust bearing. And when in backgear, since the pulley is rotating at a different speed than the bullgear, it leaves this type of mark. The solution is when pressing the bullgear back onto the spindle, place a spacer between the bullgear and pulley. the pulley should float freely when the takeup nut is snug.

As far as lubricants go, on my machine, when I used oil, the pulley and backgear would always stick after sitting for a while. I now use superlube. I have been using it for several years, and the pulley and backgear does not stick. Also the thrust bearing is the most neglected bearing on the machine, make sure it gets lubed regularly.

stay safe and have fun.

Joe.
 
Thank you Joe.[emoji846] The cone/bull gear assembly may not be factory in my machine. My lathe is a newer one that should have a "grease" stamped cone, mine is stamped "oil".

The guy I bought the lathe from had 4 or 5 10k's he bought from a trade school out East. It looks like the cone is not original to my lathe. Also there is some material missing from some of the cone gear teeth but no material missing from the back gear. He may not have assembled the spindle properly when he swapped the cone for whatever reason.

After doing some research on lapping this morning I came across info that explains why the oil is brown and hard on the bearings. Either the current spindle or possibly the original developed high spots that started wearing down. That left metal particles in the oil which probably heated up during use browning/cooking the oil. The way the wicks look, I would say very few folks ever oiled the spindle during its life regularly.[emoji35]

I will clean my the bearings best I can and use a bore gauge to check for concentricity. The spindle bearing journals don't look too bad, probably could use a good polish. For that I am considering making an external lap. I have seen a "belt" sanding attachment on a lathe used to micro polish engine crank journals but I don't know how accurate that is. At least lapping with very fine abrasive I know the spindle would still be round.

I have seen suggestions on using the NGLI-1 Superlube for the cone. That might be something to consider.



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I have seen a "belt" sanding attachment on a lathe used to micro polish engine crank journals but I don't know how accurate that is. At least lapping with very fine abrasive I know the spindle would still be round.

The polishing belts used on crankshafts are not accurate in maintaining journal geometry, but they only take off .0001 or less when used properly, so it is not much of an issue for most crankshafts. Many South Bend spindles were superfinished, which means they used a microabrasive film backed up by a hard shoe that had the correct profile and geometry built into it for each surface that was done. Not unlike lapping.

Having said all that, in my opinion your spindle does not look that bad. I think you could give it a quick polish with some gray scotchbrite and wd40, or even crocus cloth if you have any, and put it back in service. If there are any large burrs or up-stickers you can stone that spot, but over all I think a quick clean up will have that spindle fully functional. You will not affect the accuracy of the machine by doing this, and once the spindle is lubricated and adjusted it will run nicely for a very long time.

Hope that helps.

Marc
 
Thank you Mark. I agree on the crank polishing. The bearing ends look good to me. Would I like the original superfinish intact-absolutely! That said, looking pretty has nothing to do with producing accurate parts. Up to this point I have been happy with the accuracy of the lathe. The bearing journals should be ok once I clean the bearings and install new wicks. I oil the bearing cups at every use so with everything clean further deterioration of bearings should be lessened.

My area of concern is the cone journal. There are ridges on the shaft. The cone bore looks ok. I'm sure this is not the original cone now. I cleaned the cone bore and spindle with min spirits, dried then lubed with spindle oil and installed cone on spindle. It spun smoothly and freely. Thinking maybe to leave well enough alone, grease and assemble.


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Thank you Ted. Glad to see they are still available.

My oil wicks came today (thank you Steve Brooks!) so I put the lathe back together. I used min spirits to clean the bearings, oil wells and the Head stock. Blew everything dry with shop air. Lubed everybody up and stacked them up.[emoji3] The SKF bearing is very smooth. I do need a 0.032" shim though to take up space the new bearing is narrower by- old is 0.500" thick new is 0.472" thick. I will just order a 1 3/8" bore Torrington bearing washer from McMaster.

Thank you Joe for the spacer suggestion. The Bull gear fully seated and the Cone spins freely! It wouldn't do that before. Also it is much smoother when using the back gear now. [emoji1303][emoji3]

I will have to partially pull the spindle out to slip in the shim but that isn't a big deal. Now if I could get rid of that knock, knock, knock etc when the pin is engaged in the cone...


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I will have to partially pull the spindle out to slip in the shim but that isn't a big deal. Now if I could get rid of that knock, knock, knock etc when the pin is engaged in the cone...

in my experience that is from the belt splice. as the belt splice rolls over the cone the velocity changes enough to cause the torque ripple. it should go away with a load on the spindle, or a belt perfectly spliced.

i was once mistaken on this issue: the thrust load is not carried through the cone pulley. it should transfer to the thrust bearing through the shoulder on the spindle pressing on the bearing, therefore it should not matter if the thrust bearing is 1/32" too thin, except that the face of the flange on the end of the main bearing will rub on the casting. the bearing being too thin should not affect the cone pulley clearance, which is on the order of .002"

the wear on your bull gear and the cone pulley, i have no explanation for that, other than perhaps the belt was set wrong and was pulling the cone to one side. combined with lack of lubrication( i use oil myself) and you can get the galling you observe.
 
The belt is the original black unspliced piece. The cone journal on the spindle measured 1.623" on Bull gear side and 1.624 on the opposite end. Not sure if the spindle is supposed to be 1.625 on size? I did not measure the bore of the cone. I would assume it is supposed to be 1.626 for oil clearance. I suspect the wear on the shaft may be the knocker culprit in my case.


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After assembling the spindle and cone properly I see the cone floats on the spindle as it should. The thrust bearing is supposed to load on the rear bearing diameter journal shoulder, currently it does not. The old bearing was 0.500" thick, the new one is 0.472" thick. When I adjust the take up nut snug the roller thrust is not fully engaged. A 0.032" thick washer should allow the thrust bearing to fully load and position the spindle correctly on the chuck end.

If the cone journal is worn 0.001-0.002" I can see where a knock may develop. I do not plan on grinding the cone journal undersized, hard chorming, grinding then lapping to size to eliminate the knock. Once the thrust bearing is loading properly I plan on living with it the way it is. It is more an annoyance than anything. It doesn't seem to affect the finish of work pieces.


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Got the shim and installed it on Friday. The roller thrust is properly loaded now. Minimal knocking noise now. 100% better. Also lubed up the cone bore and journal and thrust bearing with Shell Gadus NGLi 1 grease. Everybody happy now.[emoji41]


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Sorry for the miss quote. I replaced the original roller ball bearing with a SKF 51107 thrust roller ball bearing. The new bearing is 0.028" thinner than the original that is why I needed a 0.032" thick cylindrical roller bearing washer. Kinda hard to find a 1.375" bore x 0.028" thick washer. The 0.032" washers for the standard roller thrust bearing are flat, inexpensive and fits in the space needed.

The SKF bearing stack up with the washer is 0.504", the original SB bearing is 0.500". The extra 0.004" is not a problem.


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