Headstock pulley removal - Nova 3000

[Henry W]

I have a Nova 3000 lathe and have already appreciated your assistance in remounting the pulley set on the motor. Now I find that i want to pull the headstock pulley set. Here's why.

When I remove the drive belt and spin the headstock by hand there is a definite point at which th ere is a grab - a stopping point. This a mechanical stoppage that is fairly easy to overcome; even spinning it by hand quickly it will make it past this point. However it sounds like a grinding action that well, just doesn't sound right.

I have access the pulley set once the cover has been removed; I see a small key on the drive shaft and on the pulley set. I have removed the set screw on that key and now want to remove the pulley and find out what is grinding there. How do I do this? It is a 6 or 7 step pulley set that is covered on three sides by the headstock housing. The end is open now that I have removed the cover, and the side where the motor pulley set was is the open side.

How do remove that key? How do I remove the pulley?

I do not feel any play in the bearings (I assume there are bearings there), and the grinding almost makes the (Aluminum?) pulleys sing (resonate) when the rotation by hand is at the right speed. That makes me fairly certain there is something grinding in/on that pulley.

Henry

[froglips]

I've seen the same sort of issue when the key was missing.

Do you ever have slipping?

Last Nova I worked on, the third side of the headstock was a screwed in thin metal cover. Had to remove 2,974 tiny screws to remove that cover. Then there were bolts holding the motor to the rest of the headstock.

The pulley "should" slide off the motor shaft and the key remains wedged in a groove cut in the shaft.

I'd wonder if something in that connection has gone bad. We ran a bandsaw without a key for a year. There was enough friction that the pulley held, but over time, the free spinning of the shaft inside the pulley wore it down till it slipped under pressure.

I relay this, as there was a physical sensation of grabbing when I'd rotate the pulley by hand.

Could be your key has sheared or isn't in the groove. The wrong size key could also be a factor.

Or, I'm totally wrong and its something else entirely

Jim

[Mike Davis]

Before you remove the pulley try this.

Mount a faceplate so you have something to grip. Hold the faceplate and try to turn the pulley.

Does it move on the shaft?

Can you tighten the set screw enough to stop the movement?

Is there something else rubbing against the pulley, shaft or ???

[Henry W]

I not only saw the key in place - I was able to move it down the shaft a bit when I pushed on it. So the key is in there and is holding the pulley in place.

Mike - I already tried what you suggested to determine if the pulley/shaft was slipping. It was not and there was no play there. I removed all the covers and the motor, and was able to see all this. No slippage or relative movement.

I want to pull off the pulley set because it seems like there is something in there causing that binding/grinding.

If the key is supposed to slide - it does. That's good. But how do I remove the key so that I can remove the pulley?

I'll have another look at it tonight, but I'm not sure what I am going to try.

henry

[Mike Davis]

The key should not move at all. If the key in in the slot and the screw is tight there is nothing that should be making a noise in there. It all works as one piece of steel, no internal movement at all.

If you have binding/grinding it has to be in the bearings.

[TedAS]

Henry,
Here is a link to the Nova Manual Scroll down to the parts list and find part #13 "Wire Form Circlip"
It looks like this clip may be inside the large end of the pulley to keep it from sliding on the shaft.

Ted

[Henry W]

A status update:
I have tried to remove the pulley set and have been able to slide it about 3/4 of an inch off the shaft. The key was relatively easy to remove, but the pulley set is simply stubbornly affixed to (frozen onto) the shaft. The motor pulley set was similar when I needed to realign that. Now that I have freed the motor pulley from the shaft once, it moves easily enough once the setscrew has been removed. I am hoping this situation repeats itself once I am able to free the pulley set from the shaft. Getting it free from the shaft remains the challenge.


Ted: Thanks for the online link to the manual. I had Googled this and always got an error trying to get onto Teknatool's website. The manual looks like the hard copy I have, although I don't recall much of that detail in the hard copy. Maybe i am just looking with "fresh eyes" now that I have tried to dissemble it.

I think that circlip is there for the bearings. Given the geometry inside that headstock casing, I can't imagine how it would be possible to install that circlip on the inside of that headstock pulley.


Henry