Chatter so bad it looks like knurl

[Dranreb]

I used to own a 10" atlas and had timken headstock bearings, i ran mine cold with .0005 clearance which is a little tight they should be about .001. The bearings are not that bad if you look around i got new out of calf. for around $250

Interesting that it ran OK set up like that.

The book says the bearings should be preloaded, adjusted after running the lathe for 30 min to an hour to warm up (a rise of 50deg fahr increases the spindle length by.002 between bearings) the end float should be taken up then the thrust nut tightened by two teeth on the spindle gear to set the preload.

Bernard

 

[Noahfreak]

This talk about vibration on concrete is reminding me of Nicola Tesla's earthquake machine. He figured out that if you vibrated a relatively small pendulum at the right frequency it would resonate and you could get the whole building it was sitting on to shake. It's unlikely but maybe something similar is occurring with the slab your lathe is sitting on? Obviously if it's just causing chatter you probably wouldn't feel it moving through your shoes.

 

[Thorn3]

My lathe once had this problem. Went through the same checks you are. Turned out to be the motor itself. It was inducing a vibration into the bed, which in turn conducted it to everything else. All cuts were 'patterned', sometimes in beautiful ways, depending on rpm and feed rate. The solution was to replace the motor. Problem completely gone. It wasn't a motor bearing problem... it was a magnetic field problem. Without pictures, it is hard to see if your problem is the same.

 

[Kernbigo]

I now own a south bend 9" wide bed, and still have a similar problem. When,and if ever my spindle bearings get a little dry i get a bad spiral chatter. If i have my 5" chuck on it is not a bad as if i have my 8" on.I'am going to add some oil grooves to the plain bronze bearings this winter and see if that helps.I run my bearings real tight which does help,+.0005.Like you i tried every thing tell i found it coming from the spindle bearings. Different motors, belts, tight bearings, loose bearings etc.

 

[outsider347]

I now own a south bend 9" wide bed, and still have a similar problem. When,and if ever my spindle bearings get a little dry i get a bad spiral chatter. If i have my 5" chuck on it is not a bad as if i have my 8" on.I'am going to add some oil grooves to the plain bronze bearings this winter and see if that helps.I run my bearings real tight which does help,+.0005.Like you i tried every thing tell i found it coming from the spindle bearings. Different motors, belts, tight bearings, loose bearings etc.

How was the chatter if you turn on centers?
My thinking was that if the chatter went away , or at least changed while on centers, it was bearing related. Mine is just as bad turning on centers.

Hope to get to the shop with all these suggestion tomorrow
ed

 

[hman]

I don t remember any directional info on the packageing sleeve when I inst. it.
I may be wrong though.
I have a new link belt in the package, & I will check
Anyone know if the link belt is directional?

ed

Indeed, the link belts you get from HF don't have directional info on the packaging. I did some web searching ... forget exactly which site gave me the info. But the recommended direction is "tabs trailing." That is, the little tabs on the inside of the belt should point away from the direction in which the belt is running.

Of course, if you're using such a belt on a lathe with a reversible motor, you'll be running it both ways. I'd suggest you set the belt up with "tabs trailing" in the forward direction, as this is used much more often.

 

[george wilson]

Happy trails to you !

 

[Jimbo]

Verify that your pulleys on your motor and head are truly aligned. This includes that the motor pulley is not canted up, down, left or right. Something easy to do when reassembling. Use a long straight edge against the side of the pulley (not running of course lol) to get a better view of the angle. A slight misalignment will cause the belt to vibrate. Also check the pulleys for dings that might of happened during the moves. Check the alignment of the head with the ways, once you remove the head from the ways you have to do the alignment. I found out the hard way when I moved mine that you cannot just put it back where it was and it does take time and patience. If all that is ok then take apart your carriage and compound slide, inspect the ways for dings, use your fingers they will feel things you can't see. Re-assemble inspecting each part and way. Good luck.

 

[chips&more]

When we re-assembled the spindle, we did put a good bit ( not really measured, but I trust my friends sense of feel) of pre load to the brgs. I think that thats how we got .0035 out of the spindle runout

Sorry to hear. I know how frustrating the chatter can be, I really do! My experience has taught me that most of the time it comes from “something is wrong with the head stock spindle assembly”. And sorry again, not understanding the 0.0035” thing. You do not want any play, no end shake, no nothing in the spindle bearings. They should be installed with a “pre”-load. The pre-load adj on my lathe is to give the spindle with faceplate attached one snappy turn. If the spindle just makes one revolution, the adj is good. I do not know the pre-load adj for your lathe, but it should be alone the same scheme…Dave.

 

[chips&more]

How was the chatter if you turn on centers?
My thinking was that if the chatter went away , or at least changed while on centers, it was bearing related. Mine is just as bad turning on centers.

Hope to get to the shop with all these suggestion tomorrow
ed

If you get chatter when turning between centers, then it’s probably not headstock related. I would then be looking at your carriage for the cause. Look for a crack(s) and/or something that is causing spring back in the tool pressure…Good Luck, Dave.