Slight wobble on in Fobco Star

[jweaver]

A few months back I managed to get a Fobco Star for a good price.. It was used in a woodwork shop and was very dirty.. But it cleaned up nicely and I am over the moon with it.

But a few days ago, I had to drill some holes and used one of the new (cheap) bits I bought of eBay.. I felt a vibration in the piece I was drilling and when I looked at the bit, the tip was 'wobbling' as it rotated.. I checked another bit and it was the same... But since I had never noticed this before, I assumed the bits were bad.. That evening I tried more bits and found a slight wobble on all of them.

I then dug out my dial gauge. I put a drill in the chuck and ran the dial gauge around it as close as I could to the chuck, and measured a deviation 0.05mm...

To be honest, I dont' use it for any precision stuff, but it would be nice not to have this wobble.. Whats the most likely cause? Obviously the shaft could be bent, or it could be a dodgy bearing.. But equally the chuck might not be on 100% true.. Problem is, I still havn't worked out how to get the chuck off, or what drift I need.

Does anyone have any thoughts or advice?

Jon

 

[Spindle]

Hi

It sounds like the chuck is either incorrectly seated on the taper or the spindle is bent. You wouldn't see a 0.05mm, (2 thou), run out so it must be being 'magnified' at the drill tip. Cleaning the taper and selective re-assembly would be my first choice once you've ascertained how to get the chuck off.

Regards Mick

 

[jweaver]

Hi

It sounds like the chuck is either incorrectly seated on the taper or the spindle is bent. You wouldn't see a 0.05mm, (2 thou), run out so it must be being 'magnified' at the drill tip. Cleaning the taper and selective re-assembly would be my first choice once you've ascertained how to get the chuck off.

Regards Mick

I just realized I posted this in the wrong section.. Sorry.. Although "Buying Advice" isn't entirely the wrong.

Cheers Mick.. I hope its not a bent shaft, as I can't be bothered to strip/rebuild it... And since its not THAT bad, I would probably live with it.. My problem now is removing the chuck.. I looked before and still can't work out how to get the chuck off...

 

[wizard]

http://store.lathes.co.uk/print/mf70

 

[jweaver]

http://store.lathes.co.uk/print/mf70

Got the doc already. It came with the drill... .And this is what puts me off disassembly, as its just too big a job for the time I have right now.

But the doc hasn't helped me understand how to remove the chuck.. It seems there are quite a few different variants of the Fobco, and I am struggling to work out the drift I need.

The only other Fobco I have seen had a slot in the quill which is revealed when you wind the chuck down.. You simply insert a drift into the slot and knock it through, pushing the chuck down/out.. But mine doesn't have this.

 

[chippy1970]

Take a photo of the chuck so we can see. On my fobco which I refurbished a year or two ago, it had a collar above the chuck that you wind down which pushes the chuck off.

Stripping them down is very straight forward with the right tools. I posted a thread about mine which will help you

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[wizard]

http://www.lathes.co.uk/fobco/

the chuck may be on a J taper that will need a wack with a hammer

 

[jweaver]

See attached.. Sorry they are a bit dark.. Did it very late last night.. Hope someone can give me a clue how to remove the chuck!

 

[wizard]

whats the number on the chuck

 

[jweaver]

whats the number on the chuck

No. 34

 

[wizard]

A 34 is a j taper the spindle should be hollow so drop a metal bar down it and whack it with a big hammer

 

[jweaver]

A 34 is a j taper the spindle should be hollow so drop a metal bar down it and whack it with a big hammer

Oh yes.. Thats a good point.. i have seen pics of the No 34 chuck and didn't think of that.. So I should be able to open the lid.. And put a bar right down the inside? I will give that a try tonight...

 

[jweaver]

A 34 is a j taper the spindle should be hollow so drop a metal bar down it and whack it with a big hammer

Didn't work.. The top of the spindle isn't hollow

When I take the top cover off and wind the chuck up and down, a SOLID shaft comes up and down in the of the pulley.

So there is no way to hit it from the top! Does anyone have any other ideas? I guess I need some kind of drift/wedge which fits it in the narrow gap at the top of the chuck!

 

[wizard]

Put something like a big allen key in the chuck and whack it with a hammer

 

[jweaver]

Done it... I went back to take a look and found that when I loosed the bolt holding the "depth stop" mechanism, it slide up revealing the screw collar that had been mentioned.

I twisted at and then turned to mole grips and finally a hammer and punch, and to cut a long story short the chuck dropped off.

Contrary to what was said above, the drill shaft had the male taper, and the chuck a female, so it wasn't hollow

Anyway.. I measured at the taper and it was off by approx 0.015mm.. I cleaned the taper and put the chuck back on and still have a wobble.

So I guess that 0.015mm at the taper gets amplified the further away from the source you get which is why I am seeing it at the tip. And I can't imagine that I will ever get it running better than 0.015mm so I guess I will have to live with this.

Thanks for your help.

Jno

 

[jweaver]

Done it... I went back to take a look and found that when I loosed the bolt holding the "depth stop" mechanism, it slide up revealing the screw collar that had been mentioned.

I twisted at and then turned to mole grips and finally a hammer and punch, and to cut a long story short the chuck dropped off.

Contrary to what was said above, the drill shaft had the male taper, and the chuck a female, so it wasn't hollow

Annoyingly, I looked at the workshop manual and this whole process was documented.. I can't understand how I missed that!!

Anyway.. I measured at the taper and it was off by approx 0.015mm.. I cleaned the taper and put the chuck back on and still have a wobble.

So I guess that 0.015mm at the taper gets amplified the further away from the source you get which is why I am seeing it at the tip. And I can't imagine that I will ever get it running better than 0.015mm so I guess I will have to live with this.

Thanks for your help.

Jno

 

[Spindle]

Hi

You could have a damaged jaw face in the chuck - open the chuck fully and examine the crests of the jaws for burs or damage.

Looking into the chuck:

Take off any damage with needle files or slip stones.

Regards Mick

 

[chippy1970]

Done it... I went back to take a look and found that when I loosed the bolt holding the "depth stop" mechanism, it slide up revealing the screw collar that had been mentioned.

I twisted at and then turned to mole grips and finally a hammer and punch, and to cut a long story short the chuck dropped off.


Thanks for your help
Jno

Yep same as mine then

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[gerrypb]

Hi, I have just bought a Fobco Universal 16 MT that needs lots of TLC. Can anyone help with the play in the quill assembly? There is barely any play in the spindle/quill angular contact bearings, spins freely and no run out. However the whole quill rocks in the lower machined part of the head casting. There is 0.003" between the quill OD and the casting ID BUT what supports the top of the quill? The drive pulley bearings are tight and there is no movment there but the top of the spindle is loose in the drive pulley and as far as I can see that is all the supports the top of the quill. Any help very gratefully received. Gerry