M6-72 Dust Cover

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Voda2000

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When I got my lathe there was a bunch of “stuff” with it that was unidentified. While lubricating my lathe today I noticed one of the random parts looks like M6-72 the inner dust covers for the headstock bearings.

I can see the one on the left hand bearing but the right hand one doesn’t appear to be installed. How critical are these?

I really don’t want to take the headstock apart if I don’t have to.
 
Voda,

I've never actually seen a 101.21400 or 618 but although in the parts manuals they call the M6-89 collar to the left of the small spindle gear a Spacer instead of a Collar, I assume that it must have set screws in it. If so, loosen those set screw as well as the one in the bull gear and you should be able to slide small gear, cone pulley, and bull gear a little bit to the left, probably enough to see in between the bull gear and the headstock casting.

To put everything back if you aren't going to pull the spindle, slide the M6-89 spacer (collar) as far to the right as the step in the spindle will allow and tighten the set screws. Pull out the direct drive pin from the right side of the bull gear and slide the bull gear firmly against the cone pulley, turn loose of the bull gear and tighten the set screw in the bull gear. After tightening the set screw, confirm that the pulley and small gear are free to rotate. There should be about 0.002" to 0.005" of end float in the pulley. If not, loosen the bull gear set screw and try again. When the end float is OK, re-engage the direct drive pin.

If you haven't ever done it, procedure for oiling the cone pulley bushings is as follows. Pull out the direct drive pin in the side of the bull gear. Rotate the pulley until you can see the oil filler plug (looks like a set screw) in the bottom of one of the pulley grooves, remove the plug and squirt some SAE 20 oil into the hole. Reinstall the plug. confirm that the direct drive pin is still out, engage back gear, and run the motor for 10 or 15 seconds. Turn off the motor and repeat the oiling steps twice more. Disengage back gear, align the hole in the pulley with the direct drive pin, and slide the pin in.
 
Thanks for the reply.

Just to close this out, it was missing so I pulled the spindle reinstalled it and reassembled the spindle. It wasn’t as hard as I had imagined. I’ve done multiple car and snowmobile bearing over the years and it was about the same level of difficultly.

Everything was oiled again (as per above) and it running a lot quieter than before.

I also found out that the gear on the end of the spindle that drive the gear train was installed backwards and only about 1/2 of the width of the teeth were being used.

I think someone had tried to do some stuff on this lathe before me and didn’t really know what they were doing...
 
OK. Sounds as though it's in much better shape now than it was when you acquired it. Good job.
 
Just to add my 2 cents.... I left off the inner dust cover on the bull-gear side of the spindle on my mill (similar setup to the lathe). It has been that way for several years with no issues. I left it off because it was not staying seated in the head casting bore. I tried to get a replacement, but did not find anything suitable from McMaster.

I don't think the inner dust cover serves much purpose. Maybe it keeps belt dust out of the bearing.
 
Looking at it after I had it apart it looks like it would help keep some of the oil in the general areas where the bearing rides.

I got lucky That the previous owner hadn’t thrown it out and I was able to re seat mine.
 
Jon,

Did you try Clausing? Those particular parts are used in the 619 as well as the mills.

Voda,

That's true. When the machine isn't running, any oil in the bearings will tend to pool in the bottom up to the height pf the bottom of the hole through the dust cover. Without the dust covers, eventually the bearings would drip dry.
 
Yes, Clausing would be my best bet. I will put that on my 'next Clausing order list' along with felts for the oil ports of my lathe. I could also turn my own dust cap and then I could fine tune the fit. I have a suitable hunk of 12L14 and also (?) Delrin.

My thought was that the slope of the inner tapered race will entrap a small puddle of oil at the bottom of the rollers.

Jon
 
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