stopping parting chatter

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.

No, tapered roller bearings are preloaded when cold and the effect of that preload is assessed at running temps. You assess the adequacy of that setting by measuring bearing temp with the lathe hot and by measuring spindle end play and run out as RJ corrected above. Preload is intended to optimize internal bearing clearances and to make sure the bearings run against the race they are intended to contact under load. Setting preload when hot will result in excessive clearances until the lathe heats up and bearing damage can occur so yes, it makes a difference and is why I queried it. RJ knows his stuff and I suspected he just misspoke, which he just corrected.
 
.... 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.

Really? I would have expected the roller elements to be tapered, which should eliminate that problem. The vertices of the cones for the inner race, outer race, and rollers should all be at a single point.

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Really? I would have expected the roller elements to be tapered, which should eliminate that problem. The vertices of the cones for the inner race, outer race, and rollers should all be at a single point.

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You are correct. I had never noticed the taper before . Thanks for pointing it out.
 
Adjusting spindle bearings seems to be a delicate procedure. Would there be any point to having an oil sump, pump and oil cooler to keep the spindle and bearing at constant temperature?
 
Adjusting spindle bearings seems to be a delicate procedure. Would there be any point to having an oil sump, pump and oil cooler to keep the spindle and bearing at constant temperature?

If the machine were in use 24/7/365 there would not be a need for any of that equipment.
 
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.
Nice. I've always been partial to Chevrolet. My first was a '55 210 2-door post with a Power Pack. I souped that one up quite a bit before I sold it. My next was one that, in hindsight, I wish I had kept. My girlfriend in '68 or '69 (who has now been my bride for the last 48+ years) knew a guy who was selling his '55 2-door passenger wagon. It was a 6-cylinder 3-on-the-tree that really wasn't particularly cool in those days. Today? Those things are actually beginning to bring as much as a Nomad, if you can find them. Then I had two Fords - but don't panic - they both had Chevrolet drive trains in them. The '65 truck had a 327 V8 with .411 positraction - that thing would fly off the line. The second was a completely tricked out all-steel 1940 Opera Coupe with a Nova suspension, 350/auto/air/PS/PDB/Power Windows, etc. etc. Then back to Chevrolet. Bought another '55 210 post. Ended up being one of the top two vehicles I've built. Loaded to the hilt with everything you can imagine. Sold it to my cousin's husband a few months ago. Built a '65 C10 for my wife that's loaded up just like that car was. That one's probably my favorite build. Just got all the gearing to change the rear-end to a .307 from the stock .377. Cruising should be a lot more enjoyable with that change-over. My truck that is closest out of the bunch to a daily driver is a '54 Chevy 3100. I put a Firebird front and rear suspension under it with auto/air/PS/PDB/etc. Started out putting a 350 in it but didn't like it. Built a 4.3 V6 instead and love it. All of 'em are lots of fun to drive, but I think I'm done building. I have a '59 Apache that I've already done the front end conversion on, but I'm likely going to sell it. Anybody who's ever done these things can appreciate how much work/time/$$ are involved. Been there/done that. Now I'm more interested in butchering metal with my mill and lathe.

Regards,
Terry
 
Mitch is right. Machines like to run. This also goes for tool post and surface grinders. Before tedious (close tolerance) work, crank it up and let it run a good while. Attended of course. Oil , bearings, shafts, and cases all heat up and the machine is much happier. As for parting hum and chatter, I run part at normal sfpm and use cross feed to match. Experiment and you'll find that speed can be your friend.
 
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