Lathe - Barber Shop Pole Pattern, Loose Carraige?

I have a 12inch, and the slowest feed is like ,004 per rev, that's ALOT of material for light duty machines
 
chevydyl said:
I have a 12inch, and the slowest feed is like ,004 per rev, that's ALOT of material for light duty machines
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Plenty big enough for good tool pressure.
Try just cramming it in manually until it does not chatter. Chatter is the mortal enemy of carbide.
 
.004 is a reasonable feed rate for parting with a low hp less than rigid machine. Like Joshua said, you have to keep the parting tool in the cut and moving on flexible machines or the chatter starts, once the chatter starts on a light weight machine, you are done for, either lousy finish, broken cutter or worse. If .004 feels to fast practice hand feeding with the lathe off, to master a steady feed. Dead on center, dead square and power thru, using either carbide or HSS. If using HSS make sure its sharp with a little relief to one side, that lets the cutter start with less than a full bite. If the part that matters is in chuck , I like that side of cutter to start first, just a slight relief is all that is needed. A great way to practice parting with less drama is to use aluminum or plastic, a bit more forgiving and the principles are the same. From there I would move up to 12L14 steel.

michael
 
coolidge said:
Yeah that's some zen spooky stuff there, maybe its unique to link belts. The different speeds make sense, the motor spins at a constant rpm no matter what feeds and speeds are set to, that was the clue that it was the belts.
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Not sure, but this video might be worth watching anyhow.

 
Appreciate the video Andre I will check my link belts for a damaged link. I may also just remove one of the belts, one is a bit looser than the other which could be generating some odd harmonics. Just for general info I measured the vibration with the factory rubber belt, the best made in USA variable cogged belt money can buy, and this link belt. The link belt produced the least amount of vibration at the chuck by far.
 
I tried a pair of heavy duty link belts on my General cabinet saw. The belting I have is a little heavier and goes together with brass pins. They did seamed a little quieter but I could never get them tight enough to not slip under heavy load. Quite possibly one was longer than the other when assembled. Went back to a pair of regular belts and no more slip. Maybe they work in a single belt application, but I sure wasn't impressed with them in a twin belt arrangement.

Greg
 
Yeah I have never had problems parting before, I've never tried to power part either, that was a first and the last on this lathe in particular. More than likely it was a chip clearing issue, after the crash when I would manually feed the chips would clockspring and get stuck, having to back all the way out to clear it, parting 2inch, with lube
 
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That's not an "issue", that's a "feature".

You need to charge extra !!
 
Update: NOT FIXED!! :burned up:

On close inspection I could still see a faint spiral pattern on facing. So I took one of the belts off to lessen tension on the drive shaft and the spiral pattern returned to the OD. So I tightened up the belts a bit more and I didn't like the sound of that. They were not super tight, there was still some deflection but the head stock didn't seem to like that noise wise. So I went back to the rubber V belts, readjusted and the spiral pattern remains. Then I went through the whole lathe, snugged up the gibs, changed chucks altogether. Re-adjusted the spindle pre-load per the instructions and nada. The drive shaft (that connects to the motor via the belts) seems tight. I don't know what the hell. Any chance if the lathe is out of level or has a bit of twist in the bed that it could cause this? I'm grasping at straws at this point.

I know this I'm done with China metal working machines.
 
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