Grizzly 4003G Lathe Chatter Problem

Okay, So I took a cut at 0, 45, and 90, chatter marks every angle, regardless I took everything apart to clean the gibs out and afterwards the problem remains. I also swapped to my brand-new four-jaw chuck to make sure the chuck was not the problem, same results with the four-jaw. I used to get glass-smooth finishes on aluminum with aluminum inserts on my machine...now I get a chattery finish that looks a bit like galvanized metal...

Im trying to keep a Thomas Edison sort of mood going now... "If I find 10,000 ways something won't work, I haven't failed. I am not discouraged, because every wrong attempt discarded is another step forward", Thomas A. Edison, Encyclopaedia Britannica
 
Do you get chatter when you feed manually vs power feed? Do you get chatter when you do a face cut?
 
I get chatter when I am power feeding and feeding by hand. I haven't paid much attention to facing cuts, but I will check tomorrow.

Reading through the instruction manual it suggests that spindle bearing preload might be the culprit. This is new to me, So I'll risk feeling silly...What is and how do I measure end-play on my lathe?

In case I failed to explain myself properly here is a link to the manual online, page 76.
 
Since you have already adjusted the gibs I'm going to suspect the tool post next. But first, did you check the compound slide gib also? Better yet, lock the compund slide & try again. If that's not it, are you using a QCTP? If yes wedge or piston type? Chips could have got caught somewhere preventing solid lock up.

You lathe is not old at all, I wouldn't suspect it to be the bearings or preload but it is possible.
 
Unfortunately I had something come up and Im out of town for the better part of the day today, but before I left I checked my toolpost, Its a piston type. Everything is locking up solid. I didn't have time to lock my compound slide but yesterday I tightened the gibs up to the max so I couldn't move them at all, and still chatter.

I also set a indicator up on surface where the chuck mounts (its specific name eludes me) and pushed on the spindle from the other side, I got 1 thou of movement. I also set it up inside and got 1 though of side-to-side play. Would this be considered normal or should there be none at all?

-James
 
Sorry my suggestion didn't work for your lathe. It worked for mine like magic. Obviously your lathe has a different problem. Do you need to tighten the spindle up a bit? There are spanner nuts on the spindles that can be tightened to bring the angular surfaces of the bearings closer together,or just put more tension on them. Get them too tight and the headstock will get hotter in use,so be careful.

You might also make sure the bolts that bolt the headstock down to the bed are all tight. Modern Asian lathe headstocks sit on a ground flat area at the right hand end of the bed. The V ways do not go under the headstock. The head can be adjusted to make the lathe turn a true cylinder. If your lathe turns a true cylinder AND faces flat,you are lucky. It is within gov't. specs for lathes to face a little hollow. This is considered good for making flanges. I prefer my lathe to face dead flat,and luckily,it does.

I'm suspecting that your lathe needs the spindle adjusted a bit tighter,but I could be entirely wrong since I'm not there to examine your lathe.


Edited: Senior moment this A.M.,aided by strong pain killers for broken fingers: I could not recall the correct name for the spanner nuts earlier. Thanks for the post below for the jog!:)
 
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https://d27ewrs9ow50op.cloudfront.net/partslists/g4003g_pl.pdf Check out this parts drawing for your lathe. Part#156 in the drawing are the spanner nuts to tighten up the taper bearings. Tighten them up enough to remove the slop but not so much that they overheat. One nut locks against the other. You need to loosen the one closest to you first then turn in the inner nut, then lock them back together.
 
Success! So it turned out that snugging up the spanner nut for the taper roller bearings solved my problem. When I pulled the cover off to access the nut, I was a little concerned when one nut with a spit in it and two set screws in there instead of two spanner nuts. I would post a picture but I'm not sure how to clear up more room for my attachments.

As everyone should, I celebrated by blowing up 4 pounds of tannerite! :))

Thank you everyone for the help and advice, without all the extra help this process would have been much more difficult. Hopefully I can whip up a fantastic thread to pay everyone back!

Thanks again,

-James
 
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Yup, congrats, good to hear!
 
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