How to adjust pulley assembly on drive shaft?

[Henry W]

I am a new turner and bought a used Nova 3000 (I think that is the model). The drive pulley assembly is a single piece with several size pulleys. The position of this assembly seems have gradually shifted on the motor shaft, away from the motor. There is a key and keyway on the shaft, with a set screw.

I have loosened the set screw, wanting to shift the pulley assembly in towards the motor. It does not budge. While I could start to use force here, I thought I would ask advice first.

How do I shift the position of this pulley assembly when it seems stuck?

Henry

 

[Gotcha6]

First of all, be sure there isn't a second set screw on the pulley hidden in a belt groove. Apply a little penetrating oil & let is set a few minutes. Use a wooden block and hammer to tap the pulley back onto the shaft. If the shaft is sticking out past the pulley, a deep socket will work as well, but hit it with a mallet or brass hammer if you must go this route. You want to make contact on the pulley as close to the center and consistently all around so there is no bending of either the shaft or the pulley. If it's a steel pulley and not pot metal, you may have to resort to heat, but if it's slipped out already it shouldn't be seized that badly.

 

[Dudelive]

From the manual this is what it says:

7.Fit the key into the motor shaft
keyway. Align the keyway in the
motor pulley to the motor shaft and
slide the pulley onto the motor shaft.
Leave about 13 mm (1/2-inch)
between the pulley and motor.
Loosely secure the pulley to the
shaft with a M8x10 set screw with
an Allen wrench.

So be sure there is that space I am guessing. The picture shows one set screw and one keyway, with the larger pulley towards the motor.

If this is the Nova 3000, manual can be got below:
http://www.teknatool.com/products/Lathes/3000/downloads/Nova3000manual.pdf

 

[Henry W]

Thanks for the offer of the manual, but I have it. The given description does not really help me - because I can't slide the pulley assembly on the shaft.

Well I had a few clues that the pulley had shifted.
- the first was that the gap to the motor was more than 1", not 1/2".
- Second, the pulley did not align very well with the mating pulleys in the lathe headstock (approximately one belt width off).
- The third clue was that the smallest portion of the pulley, farthest away from the motor, was rubbing on the casing as it turned, and I doubt it should be.

I guess it's OK to use a block and a mallet - which I tried without much persuasive force - to no avail.

I have not yet used any penetrating oil - that's next - as well as a little more persuasion.

Any more advice?

Henry

 

[Dudelive]

Not knowing what material the pulley is made from, I would tilt so as to get penetrating oil in between pulley and shaft. Be sure there is no rust on the shaft between pulley and motor, polish it . Let the oil soak overnight and check to see if it needs more sprayed next morning. I would use a heat gun NOT a torch to heat the pulley. The heat should cause the pulley to expand allowing movement. If it moves keep it sprayed so as not to cause the pulley to gaul and get real stuck. Move a little soak a little heat a little.

Be careful tapping on the pulley. The motor can get damaged if you hit it too hard you can possibly damage the endbell or endbell bearing of the motor.

 

[Henry W]

Thanks for the replies. Your description of how to move/remove this is very helpful.

I guess it would help me if I had a mental picture of what this assembly looks like.
- Is the motor shaft a straight cylinder - with a key way cut into it at the appropriate spot? That's what I am guessing at least
- What is the "endbell or endbell bearing of the motor" that you describe? I have not heard those terms before and I haven't used Google or Wikipedia to try to determine their meaning.

Henry

 

[DaveD]

I don't know about that particular machine but make sure there is not a SECOND set screw under the first one.

Some motors you can look at the end of the shaft and see that the keyway is cut pretty much the length of the shaft. If you have this kind you can sometimes put a thin, flat bottomed punch in the groove and tap the key itself to break it loose. it has to be a flat bottomed punch though.

You don't want to hit it very far because it (the key itself) could end up hitting into the machined end of the slot that rises up to the shaft diameter. In this case you will just jamb the key in there even harder and have a heck of a time getting it apart.

On other motors the 'key is actually a half circle kind of key set down in a half circle cut in the shaft. You can't see this kind until you get it disassembled.

You could also use ome 'PB Blaster' penetrating oil and a heat gun on the pulley. Once you get the pulley 'warm' take an ice cube and put it on the end of the shaft to cool it a little for a few seconds.

Lastly, If you can get some 1x lumber behind the pulley then take the motor out of the machine, flip it so the shaft is vertical with the pulley facing up, put two boards behind the pulley, support it by the pulley on the boards and tap on the motor shaft with a soft faced hammer or put a piece of board on the shaft to hit.

Be sure that you support the motor somehow so if the shaft comes loose the motor doesn't crash to the floor.

If all that fails then find someone with an arbor press to press the shaft out.

The pulley is probably pretty fragile so don't go banging on it around the outside edges.

 

[Henry W]

Dave: Thanks for the ideas

I have the motor off the lathe - and as far as I can tell this is a square key in a slot that only goes partially along the motor shaft.

I may use your ideas to break this free.

Henry

 

[DaveD]

Also dump penetrating oil down the set screw hole once you take the setscrew out.

Henry, I just sent you a PM.

 

[Henry W]

Pulley position adjusted on lathe shaft

All: Thanks for all the input on how to adjust the position of the pulley stack on motor shaft of the lathe.

I removed the motor from the lathe and suspended the motor inside a metal pail, supporting it by the lathe mounting plate; this mounting plate was fixed to the motor case and located between the motor and the pulley. I had sprayed some penetrating oil on the shaft in around the key and let it sit for a while. I then forced long thin wedges between the pulley and the mounting plate to gradual shift the pulley assembly off the shaft. It held tight to the last moment.

I then cleaned up key and keyway of accumulated grit and reassembled the pieces. With clean and burr free pieces I now have a 'feel' for how easily this piece should shift along that shaft.

It works fine - as long as I remember to tighten the set screw once the motor is mounted and pulleys aligned.

Henry

 

[Gotcha6]

Congratulations! You're now a Motor Mechanic.:icon_thum
Now, git back t' turnin'!:eusa_danc