Thread: Loose Cone Pulley?

Hi,

I've noticed over time my cone pulley has become loose on the spindle. It has about 1 mm free play. I've looked over the ToT and Hercus 260 Maint Manual and can't seem to find where to tighten it (I think but not sure could be page 11 Removing/Replacing headstock spindle).

Am I missing something? Any help would be appreciated.

Ben.

The cone pulley is bushed and floats on the spindle.
It transmits torque to the bull gear via a retractable pin.
The bull gear is keyed to the spindle, and unlikely to develop 1mm of play I think.
Could be the pin or its holes in the bull gear or cone pulley end face is worn.
Or, backgear has been extensively used without ensuring lubrication (grubscrew in a pulley V), leading to wear.

Jordan

Hi Jordan,

The bull gear isn't loose, the cone pulley is. I forgot to mention that in the last 3 months (or longer) I've noticed old rusty brown oil coming out of the cone pulley and flinging around. I've always oiled the back gear even though I've haven't used it much.

I understand what your saying about the pin in the bull gear. I'll have another look in the morning and maybe take a photo.

Ben.

Hi,

Used my lathe some today.

The cone pulley is definitely loose on the spindle. It has left/right movement of less than 1 mm. There's oil leaking out, you can see it in the photo - brown oil.

There is wear in the bull gear pins but not that much.

Any ideas?

Ben

If you look at the cone pulley, at the bottom of the second Vee groove from the left, there is a threaded hole blocked with a grub screw. You are supposed to regularly remove this grubscrew and to squeeze oil into to lubricate between the main spindle and the cone pulley. If I remember well, the cone pulley has no bushing as such, it runs directly on the spindle (if I remember well, it is years ago I had it apart...). There is a coarse "cross thread" of about 20mm pitch cut into it as an oil groove. Of course, the oil comes out at both ends of the cone pulley and makes a mess. In the US the Southbend lathe users (the 260 is a Southbend license) have replaced the oil with a special grease that seems to last for many months, it is called Synco Superlube and is a synthetic grease with added Teflon (PTFE). It is quite expensive in Australia, but if you are patient you can find it on eBay - I got two tubes of 100g each from a Korean seller for under $50 including postage. This grease look milky/semi transparent, a little like vaseline.

If your cone pulley has one mm play it means it has been running dry and is now worn out. You have a problem. No oil will stay in there for longer than 10 minutes. No grease will stay in there for longer than a day. You have to remove the spindle to check the cone pulley and assess the damage. Then either find a replacement cone pulley, or you try yo make a bushing for it. Hopefully only the cast iron pulley is worn, and the spindle is not scored too much. Next time oil the cone pulley daily when using the slow speeds, or else use the Synco PTFE grease that should last several months before you need to add a squirt. Chris

PS: This is the Synco website, at the left menu click on "case history and endorsements", then click "endorsements", then click on "Southbend lathe bearings", then you will see a page where the Southbend lathe factory recommends this grease specifically for their cone pulleys (and only for the cone pulleys, everywhere else they recommend oil).
http://www.super-lube.com/synthetic-...se-ezp-49.html

Thanks for the reply CBA.

I spoke to Mal last night as well. I would be lying if I said I oiled the spindle every time I used it, so I think that is the problem. I only noticed the brownish oil coming out in the last six months or so. Bummer. I've been using a air compressor oil mixed with a little bar oil for pretty much everything in my workshop, I'll try something heavier in the cone pulley and see how that goes.

On a side note, I think we used to use a similar grease on our heavy weapons over in the sand pit(s) as it didn't attract as much sand as normal oil.

Thanks Ben.

Ben
There seems to be corrosion (rust) on the large diameter of the cone pulley, Cannot figure where that has come from, however it may be linked with the problem presented.
Just a note of caution, I am often removing the 1/4" BSW slotted grub screw on my 260 lathe to lubricate it.
It is very, very easy to drop it & lose the grub screw, however in 22 yrs that has not happened, but I came close yesterday.
Suggest placing a piece of paper under the cone pulley before attempting to undo it, & then use a magnetised screwdriver which will grip the screw as it is undone.
Same for reassembly.
regards
Bruce

Originally Posted by bwal74

The cone pulley is definitely loose on the spindle. It has left/right movement of less than 1 mm.

If the play is only in the left-right axis, you might be in luck.
Side play can be more easily dealt with, by shimming or making a longer spacer to the left of the cone pulley perhaps, taking care not to interfere with the taper bearings' adjustment.
Sorry about saying the cone pulley is bushed - my mistake.

Jordan

Originally Posted by Abratool

Ben
There seems to be corrosion (rust) on the large diameter of the cone pulley, Cannot figure where that has come from, however it may be linked with the problem presented.
Just a note of caution, I am often removing the 1/4" BSW slotted grub screw on my 260 lathe to lubricate it.
It is very, very easy to drop it & lose the grub screw, however in 22 yrs that has not happened, but I came close yesterday.
Suggest placing a piece of paper under the cone pulley before attempting to undo it, & then use a magnetised screwdriver which will grip the screw as it is undone.
Same for reassembly.
regards
Bruce

Hi Bruce,

I'm not sure if your referring to some staining on the actual cone pulley, if yes then that's been there for as long as I've had the lathe. The actual brown oily fluid is the oil that 's coming out of the cone pulley and getting everywhere. I've left my feeler gauges at work so I've yet to accurately measure the left/right movement of the cone pulley but I believed it to be significant. As I said before it didn't happen when I first bought the lathe (the internal of the headstock where much cleaner). And I must admit, I didn't lubricate it every time I used the lathe so that could be the cause of the problem.

I've yet to drop the grub screw but sure it will happen sooner or later. I use a magnetized screwdriver as well.

Cheers Ben

Ben, just in case you do not have seen this:

Hercus_260_Headstock.jpg

There is no problem with left to right (as in, along the axis of the spindle) play in the cone. There needs to be some room there to allow the bearing preload nut to actually close up the inner bearing races as required. If there was no play, it would lock up the left bearing's inner race against the pulley and prevent it from rotating, as well as stopping the bearing from having any more preload being added, so that end, the play is essential. Mine has quite new bearings in it and i have about a mm of play in it.

Play on any other axis is a problem though, as said above, all yer oil would fall out pretty quick. I load up the inside of the cone with oil every time I run the lathe in backgears. If its direct drive, there is no need to oil up. If it was flinging rust laden oil, thatd be reason enough for me to pull the spindle and assess whats going on in there. Rust is not a good lubricant. Just to be clear, youre adding oil under the screw at no. 121 and 132 on the above diagram? There is a bunch of other ones on the headstock, but those two are crucial to the backgears running right.

Hi Scotty,

I am definitely putting oil in those two spots. There's 0.35mm of left/right play in the cone pulley and it does fling oil pretty every time I use it.

It is concerning me. I might see if I can get Mal around here to have a look. I think I do need to pull apart the spindle.

Ben

.35mm is fine. If you think its flinging excessive amounts of oil, the clearance between the pulley and the spindle might be too large. If you relax the belts, can you move the cone backwards and forwards? Mine flings a little oil, but there's a lid and its never enough to concern me.

Hi Scotty,

I don't have to loosen to the belts to move the cone pulley backwards and forwards. I did think this was simply the bull gear pin hole being a bit big/worn? It probably moves about a mm or less.

Ben.

Hi Ben,
There are 3 different directions of play possible here, to me they are getting confused...(or is it just me)

There is the axial (side to side) play, the pulley moving along the spindle from left to right;
There is the rotational play, the pulley having play on the bull gear pin,
And there is the radial play, how much clearance the pulley bore (which i'm surprised isn't bushed with bronze-it is on the Mars) has on the spindle.

The first 2 are not a big problem, but the 3rd is.....

Ew