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[shaunburgess]

Guys (this is generic term non-gender specific),

My wife's lathe (made by her engineering sister), has developed a serious problem. We put a Nova midi chuck on the headstock (i have no idea about lathes) it now has a pronounced wobble and everything turned is now oval shape. I suggested we ditch above lathe a buy a new one but apparently this is not a good idea as it has sentimental value, but little else, therefore i have had to work out what is wrong without taking it apart. I think the bearings in the headstock are shot and not running true, would the resulting oval shapped turning be caused by this? The lathe is belt driven with the pulleys in between to bearing casing's driving a shaft which the chuck is screwed onto, the only other thing that i could think of being "out" would be the actual shaft, but this was machined as part of a school course, and it would have been checked by both student and teacher (i hope) and idea's? :confused:

[Captain Chaos]

Hello Shaun,
It seems to me that the bearings in your headstock could be worn rather badly. Is there any noise ( either knocking or rumbling ) coming from the the headstock area when the lathe is being used? When the lathe is turned off grab hold of the chuck / spindle & see if there is any vertical / horizontal movement in the shaft / bearing assemblies. Also pull the shaft to check for excessive end float - there should be virtually nil movement in this direction.
Failing that, is there any wobble in the chuck when the spindle is rotated slowly? If so, the end of the shaft could be bent, due possibly to a severe dig in? :eek::eek:
If the bearings / housings are worn, it is just a case for replacement. Take the old bearings to a bearing supplier (BSC, CBC etc.{ South Oz } ) & they should be able to match the bearings for you. If the shaft is bent, then I think that a new shaft is the best way to go.
I hope that this is of some help to you AND the Bride.;):)
Regards,
Chaos ( Barry )

[Sprog]

Is it only with the chuck fitted you are getting oval turnings?
If so:-
Are the chuck jaws fitted to their corresponding jaw slides 1 to 1, 2 to 2 etc.?
Are the jaws fitted correctly to their jaw slides as per the instruction manual?
Is the chuck bottoming on the headstock spindle shoulder or is there a gap?
If there is a gap you need to fit an appropriate washer between the chuck and the shoulder.

[soundman]

:eek: wood turning wife? :eek: engineering sister?
Sounds like you could be in one heap of trouble. :D

As before jaws in the right way would be a good start.

If all else fails. convert the "airloom" lathe to a disk sander and buy a new one. Airloom disposal is punisable by death or worse, airloom conversion may be permisable. :rolleyes:
cheers

[tonysa]

can I hijack your thread shaunburgess and ask whats involved generally in replacing bearings on spindle and headstock.

Puller, soft metal drift and or heat ???

[gatiep]

Is it only with the chuck fitted you are getting oval turnings?
If so:-
Are the chuck jaws fitted to their corresponding jaw slides 1 to 1, 2 to 2 etc.?
Are the jaws fitted correctly to their jaw slides as per the instruction manual?
Is the chuck bottoming on the headstock spindle shoulder or is there a gap?
If there is a gap you need to fit an appropriate washer between the chuck and the shoulder.
"
If so:-
Are the chuck jaws fitted to their corresponding jaw slides 1 to 1, 2 to 2 etc.?
Are the jaws fitted correctly to their jaw slides as per the instruction manual?"

That will still give a round object but with an offcentre center.


"Is the chuck bottoming on the headstock spindle shoulder or is there a gap?
If there is a gap you need to fit an appropriate washer between the chuck and the shoulder"

This is a big possibility and maybe the thread on the spindle nose is not 100% perfect fit.

If the bearings are shot etc they'll make a noise long before they allow the shaft to wobble.

[Ashore]

shaunburgess as to your post

"therefore i have had to work out what is wrong without taking it apart."
This is always a difficult way to solve a problem
"The lathe is belt driven with the pulleys in between to bearing casing's driving a shaft which the chuck is screwed onto"
This I can't understand, what do you mean in plain English
Perhaps a picture would help as your grasp of the technical leaves much to be desired.

As far as the job wobbles I would strongly suggest that you correct the problem before allowing you wife to use the lathe again as I fear there could be greater problems .



. The trouble with life is there's no background music.

[shaunburgess]

Thanks for your input guys, i will take pictures tonight and try to explain problems in plain english using pictures.

The chuck "should be o.k." as pre assembled when we purchased it at the www show we use an insert which was machined by engineer's so that should be ok as well. It seems the shaft was not spinning stright (or round) before the new chuck went on but the wobble is being increased by the weight and or length of the chuck. Hopefully the pictures will show problems.

Thanks