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Can't figure out how to align lathe pulleys

ovidiumght

Plastic
Joined
Oct 26, 2018
I bought a few months ago an old italian lathe. It was built in 1933 and it was in a rough condition, but I can see the original owner took great care of it. (I think it was neglected by the person that sold it to me, he was not a machinist).

If you have any information about this lathe it would be greatly appreciated. The brand is Mercurio made by a company called vdf or vfd. Couldn't find any other info on it.

Now my problem. The flat belt cone pulley on the bottom of the lathe is not alligned with the cone pulley in the headstock. This causes the belt to rub against the whole left side of the inner headstock wall. This didn't happen when I first tested the lathe.

I took the whole lathe apart, cleaned and oiled it and now this is the problem. Do you think I am missing any pieces or I did something wrong?

Any ideas are welcomed.

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There is a famous lathe that uses flat belts, South Bend.
Here is a copy of the manual. It shows how to adjust the belts. Probably similar. On some machines the lower flat belt drive can be offset buy threaded rods the intermediate section hangs on. Also if you use a thin straight-edge like an aluminum yard stick and rest the side against the top and bottom pulleys.

http://vintagemachinery.org/pubs/1617/17726.pdf
 
Shafts need to be parrallel in that arrangement. Belts will track to the high side of a pulley. Lift or lower one end of the countershaft and spin it over by hand/apprentice until it's where it needs to be.
 
Did you disassemble the lathe when you moved it? Is it possible you mislaid some parts? If you misplaced a spacer washer (thrust washer)on the lower pulley that could have shifted its axial position. If there were shims under the bracket for the lower pulley and they were lost or put in the wrong locations that could have put the shafts out of parallel.
 
Thanks for the answers.

The thing is the lower pulley is more to the left than the headstock pulley. It seems to be that way from the factory. This isn't about some small missalignment, I see no way how this system could work. I thought maybe I am not seeig something obvious.


I did take it apart but didn't miss anything AFAIK

Here it is before taking it apart:

2:ROFLMAO:627_183943.jpg - Google Drive
 
The problem is not a small missalignment. The lower pulley is at the left edge of the lathe and the tailstock pulley is in the middle. The difference is 15 cm, it's not a fine adjustment.

I wonder if this might be a shaft driven lathe that was later converted to use a motor. It sure doesn't look that way.
 
I also want to mention tha I am not a machinist, and this is my first lathe. So it might be something obvious I am missing.
 
Get more photos and better photos. Concentrate on the area where the lower belt pulley is mounted and how it is attached to the machine or to the floor.
 
Is your problem that the belt is rubbing on the inside of the gallery? If so there might be some missing rollers in there, or that they are just seized.

Like these ones on my friend's belt-driven Empire lathe
 

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Your second set of photos are much better. The hinged casting that the bottom cone pulley is shafted to, looks like it should slide further towards the outboard end. In the first picture, it looks like the outboard pin is not seated all the way into the hole.

If it is possible, remove the belt and take several pictures of the bottom pulley assembly, at all different angles.

Maybe you are missing a simple bushing... ?

Brian :)
 
It's true that the bottom pulley can be moved along it's axis a few mm.

After playing with it for a bit I notices that if I let the flat belt a little loose the rubbing is not so bad.

Peter was right, the rubbing is inside of the gallery.
 
Likely, Peter is right and you're missing a roller inside the gallery.

However, I do have another question: how is the bracket holding the lower pulley attached to the pedestal? Are there threaded holes in the pedestal, or circular slots and a plate with threaded holes on the other side of the pedestal wall?
If it is the latter, I suspect that the pulley could be adjusted in position to tension the belt and your problem is that the belt is too long. But I could be completely wrong. Hard to guess from the pictures.

Paolo
 
Remove the leather pin or pin in the belt and put the belt on the outside of the casting in back, you can eyeball the OD of the pulley through the opening and if you look outside the casting it's a clear shot from top to bottom. You or the old owner installed the belt in the wrong location. The also could be a tightening pully missing in the center, I see 3 mounting holes. But I am pretty sure by loosening the connector pin and sliding the belt behind the back casting and head shaft and reinstalling the pin you will solve your problem. Rich
 
It does look for all the world like there's a clear line but I guess if Ovidiu says it fouls then it must do.

Some better photos would help but looking at this one there seems to be a hole and two large locating dowels on the pedestal below the small back-gear pinion. This might be where a support block for an external belt roller should be mounted.
 

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