stopping parting chatter

[savarin]

Attempting to part off the end plates for the possible steam engine produced the most horrendous screaming chatter I have ever heard.
I really thought I had solved all these problems by using the solid plinth for the tool post.
I tried everything to try to solve it but nothing worked.
Then I had a thought, some time ago I had replaced the taper roller headstock bearings and set them to the correct preload but hadnt seen a need to touch them since.
The bearings didnt feel loose but Yep, a small increase in pre-load and and all is well in the world.
Back to parting like a dream.

 

[Reddinr]

Best way to stop parting chatter? Stop talking about it! Well, it was funny in my head...

I'm going to have to check my pre-load which I have not done in a long while. I have a big honking lathe and still have parting issues from time to time. I've done the other fixes that are normally done but still problems. Thanks for the tip!

 

[savarin]

I hope it works. For my lathe its tighten up till a good pull on the chuck with no belts connected and it should just make 1 turn.
If the headstock gets too hot to touch after 10 mins its too tight. comfy warm is ok.

 

[RJSakowski]

My very first experience with tapered roller bearings was on my 1963 Buick. Being used to ball bearings, I put a significant preload on the wheel bearings only to find that I ruined the hub when the bearings heated up and swaged the hub as a consequence.

Tapered roller bearings should be adjusted after the machine has come to working temperature. If the bearings are too hot to touch, there is too much preload and it will lead to bearing failure.

edit: A roller bearing will have only one point of contact in a true rolling mode points along the line of contact other than that singular point will be slipping which causes friction when overly tightened. Not true. The rollers actually have a slight taper to provide a true rolling motion over the line of contact.

Thanks for correcting me, pstemari.

 

[tjb]

My very first experience with tapered roller bearings was on my 1963 Buick. Being used to ball bearings, I put a significant preload on the wheel bearings only to find that I ruined the hub when the bearings heated up and swaged the hub as a consequence.

Tapered roller bearings should be adjusted after the machine has come to working temperature. If the bearings are too hot to touch, there is too much preload and it will lead to bearing failure. A roller bearing will have only one point of contact in a true rolling mode points along the line of contact other than that singular point will be slipping which causes friction when overly tightened.

What model was your Buick? I had a '65 Wildcat. Too big; didn't like it. But the '60's Skylarks were nice.

 

[RJSakowski]

What model was your Buick? I had a '65 Wildcat. Too big; didn't like it. But the '60's Skylarks were nice.

I had a number of Buicks over the years from 1966 to 1978. My first was a 1958 Buick Roadmaster 75. It had a Wildcat 364 cid engine with torque converter shifting, airbag suspension instead of springs. It was was fastest ride ever. The speedometer went to 130 and then started to roll over. I once made a trip from Madison, WI to Stevens Point WI, a distance of 100 miles in 58 minutes with one tire change along the way. I bought a set of four Michelin radials when I got back to Madison. On a stretch of straight road, I passed around twenty cars in one go. Thankfully, there were no cops and cell phones hadn't been invented yet. There was more chrome on the inside than others cars had on the outside and it had heated seats.

My second car was a 1963 Buick Electra 225 that my ex bought while I was in Ft Riley, KS. That was the one with the roller bearings. We took that car out to the west coast and cruised at 120 mph in those states where the speed limit was R&P.

Number three was a 1962 Buick Electra convertible. It was my favorite. With the top down, it was a sleek car. With the lower than normal center of gravity, it cornered well. I used to enjoy cruising the back roads with the hills and curves. It was a $25 car. Some kids had taken it joy riding and had managed to spin off the oil filter so they dumped it. The owner saw no oil pressure and figured they blew the engine and he just wanted it gone.

 

[benmychree]

Another way to stop chatter is to buy a big heavy lathe ---

 

[mikey]

Tapered roller bearings should be adjusted after the machine has come to working temperature.

RJ, are you sure about this? My experience suggests otherwise but perhaps I've been doing it wrong.

 

[SamI]

RJ, are you sure about this? My experience suggests otherwise but perhaps I've been doing it wrong.

It depends on the sped you run your lathe at. If you rarely use higher speeds I doubt it would make much difference either way but after 20 minutes or so at max speed the bearings, and therefore the spindle can get rather hot. As the spindle heats it expands which increases the preload further increasing heat build up. My guess would be that the bigger the lathe the more of a problem this becomes - after all a longer spindle will expand more for a given temperature increase.

 

[RJSakowski]

RJ, are you sure about this? My experience suggests otherwise but perhaps I've been doing it wrong.

Maybe checked would be a better word than adjusted.

It would depend on the recommended procedure for the machine. Ideally, you want zero axial or radial end play under operating conditions but not so much preload so as to cause adverse friction and subsequent overheating. Since the separation between the bearings varies with machines, the thermal expansion of the spindle and therefore the amount of preload will also vary. But the final decider should be the spindle temperature.

In absence of machine specific instructions, I go by operating temperature, and axial and radial play as these are the conditions in which the machine is used.