Side Play Issues....

[captainneek]

Hello everyone,

today's problem is too much side play on my Boley & Leinen  8mm. lathe. The end play is of course adjustable but how does one go about reducing the side play on cone bearings, is lapping advisable ?  Any thoughts, hints or advice will be greatly appreciated.

Cheers, Mike

[HectorLooi]

I don't understand what you mean by side play. With conical brass bushings, when the end play is adjusted correctly, there shouldn't be any side shake.

Do you mean that the spindle can rattle around in the headstock? Or is there a waggle of the round bar in the collet?

What kind of collet are you using? Have you tried another collet or chuck?

[captainneek]

Hi, this lathe has hardened steel conical bushings and even with the adjusting nut tightened up so there is free  rotational movement of the spindle but no end shake, the spindle can still be moved axially by a small amount. At the moment I am using a three jaw chuck.

[HectorLooi]

Hmm... Sounds like a very well worn lathe or the front bushing has drifted. You could try putting a washer under the locking ring to apply more pressure on the back bush. I adjust the amount of play on my lathes by tightening the ring until the spindle locks up , then back it off until the spindle can turn again.

[nickelsilver]

It would take many thousands of hours of abusive use to wear the cone bearings to the point that they had radial play with the bearings snugged up to zero axial play. For the spindle to turn there has to be some play, let's say it's adjusted to a bare minumum to allow oil to flow, like 0.005mm: if checking something like a 3 jaw chuck that will be perceptible. If using an indicator to measure it might seem like a lot; but in use, the oil creates a hydrodynamic film that is very rigid.

 

You have one of the highest quality lathes ever made- I would be curious to see what the bearings look like. For them to be worn they will look horrible. But bottom line, there is only one adjustment, the adjusting nut at the rear of the spindle. The cone bearings (which have two conical bearing surfaces each) should adjust both radial and axial play simultaneously.

[HectorLooi]

15 hours ago, nickelsilver said:

It would take many thousands of hours of abusive use to wear the cone bearings to the point that they had radial play with the bearings snugged up to zero axial play.

Or just one episode of severe abuse, like bashing the spindle in the wrong direction to remove the spindle.

[HectorLooi]

Hmm... On further thought, bashing it in the wrong direction would actually close the distance between the bushings and make it tighter.

Not suggesting that you bash your spindle in.

[captainneek]

Hello both,  I will follow Nickelsilver's suggestion and try and send a couple of photos so we can see what we're dealing with.

In the meantime, thanks for your comments 

[captainneek]

Hello, dismantling the headstock to take some photos I discovered the cause of the problem....it was hardly noticeable. Under magnification I noticed that the locating pin for the collet (in this case, the 3 jaw chuck) was slightly proud of the spindle. A smart tap with a fine punch (and with a collet inserted in the spindle)  and the pin moved below the surface. After a quick clean, lubrication, rebuild and test run the lateral runout is acceptable.......problem solved .

Thanks again to HectorLooi and Nickelsilver for their interest and suggestions.

Mike

 

[HectorLooi]

I had this problem with my first lathe. Some collets have a shorter cutout and when tightened fully, it will push the index pin out. 

Check your collets for any with short cutout grooves. I had to use a grinding disk to cut the slots longer on a few of my collets. 

[captainneek]

Great idea, thanks for the tip.

Cheers, Mike