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Lathe bearing wear

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OldWood

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I have Wadkins Bursgreen lathe which must be in the order of 40 years old and have compared its running noise with the Graduate that a friend has. I always feel that the Graduate is more noisy and although there is no apparant bearing slackness, I have offered to check this lathe with a dial gauge for bearing wear.

I tried checking my own lathe this afternoon, setting up the gauge on the underside of the chuck and applying load from the top downwards. The deflection I was getting was dependent on how much I pressed down with a maximum in the order of 2 thou (inch) when I applied quite a lot of downward weight. The deflection was sort of linear with force rather than a step which would have indicated bearing slackness I think.

Can some one supply some knowledgeable opinion on this - is this a valid way of checking bearing wear for instance ?

Thanks
Rob
 

plymouth pirate

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OldWood":3ot49xja said:
I have Wadkins Bursgreen lathe which must be in the order of 40 years old and have compared its running noise with the Graduate that a friend has. I always feel that the Graduate is more noisy and although there is no apparant bearing slackness, I have offered to check this lathe with a dial gauge for bearing wear.

I tried checking my own lathe this afternoon, setting up the gauge on the underside of the chuck and applying load from the top downwards. The deflection I was getting was dependent on how much I pressed down with a maximum in the order of 2 thou (inch) when I applied quite a lot of downward weight. The deflection was sort of linear with force rather than a step which would have indicated bearing slackness I think.

Can some one supply some knowledgeable opinion on this - is this a valid way of checking bearing wear for instance ?

Thanks
Rob

Try lifting the shaft and that will give you any idea of wear. The shaft is lying by its own weight at the lowest point so pushing down is going to achieve very little.
 

flh801978

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I have had endless problems with a graduate lathe that a friend has. He was concerned that he was getting catches because of a looseness somewhere on the shaft and lack of concentricity.
firstly the new patriot chuck he had bought exhibited eccentricity in the order of 5-10 thou so that went back to be exchanged for a new one which luckely was smack on the chuck itself but the alloy back plate was still out but we let that pass
I have fitted 2 other spindles with the unsealed bearings ( one new set and one used set) no amount of grease would quieten them down so I eventually fitted sealed bearings ( 2RS) the lathe is now silent
However we were concerned to see that we could lift the spindle up and down about 2 thou using a dial gauge off the body of the lathe...if i used the bed the error was greater leading me to believe that cast iron isnt quite as ridgid as some make out..bed bolts were tight....
this movement was only up and down nothing at all side to side leading me to think that the bearing housing in the pedestal was at fault so I removed the shaft again measured the housings which are 80mm dia there was no wear in these using bore micrometers to measure... I reassembled again and spent a long time setting the end float and the movement has been taken out.. I can only assume that the movement was to do with the balls clicking against each other when some end float was present....you could actually hear a click when lifting the shaft with chuck mounted or a long bar through the spindle.
the bearings were new skf bearings too

having said all of that i have 2 graduates set up in my workshop and neither of those show any movement anywhere and I have found the end float to be not that critical

At the moment hes happy with it...time will tell if the play returns
 

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