help with lathe turning

D

dcheff

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I am new here so let me say thanks for the great amount of info on this site. secondly sorry for my poor typing skills.

I just bought a rockwell 11" lathe from my friends dad. when picking it up he used chains and a front end loader to load it onto my trailer. i noticed after he set it down that he had one chain wraped around the table and the lead screw. after i got it home and installed it i checked the lead screw and it is bent slightly. when using the automatic feed in either direction, at any speed, cutting any material it leaves small noticable lines usually about 3/16" apart from each other all the way down the length of the work. whil cuttin i have noticed that the timing of the lines is exactly one line per revolution of the lead screw.

I tried adjusting the half nuts, went through with the manual and adjust everything to try to eliminate any possible problems. it is still there. could a slightly bent lead screw cause this or should i be looking else where?
 
If you're positively absolutely definitely certain it's the bent leadscrew then there are some instructions over on the other forum on how to straighten it (I might get in trouble with a link so you'll have to Google the term "straighten leadscrew")
But that might not be the problem. When you change the feed rate instead of the speed does that change the width of the line? You might just be seeing the normal result of feeding at a rate faster than the width of the cutting tip. Try changing the feed rate down to the smallest setting possible and see if anything changes. I don't know the Rockwell lathes so I don't know if you're just flipping levers or changing gears to do so.

Joe

EDIT: You said you were new here so let me just say "Welcome to the Hobby-Machinist - the second friendliest place on the entire internet."
 
im positive the lead screw is slightly bent, its not majorly bent but its is slightly bent. also when the half nut engage it it lifts the lead screw up a bit like it is out of alignment. i will take a picture of what it does tonight. the lines are always there, i usually cut on the slowest feed speedso if anything i am feeding to slowly. i am not positive that the lead screw is the culprit, just what i am thinking but i am a novice with this stuff hence why i asked lol.

ps what is the friendliest place on the net?
 
First off let's address the line. When you have the auto feed engaged the half nuts cannot be engaged. They are locked out. Now a bent lead screw is a big problem. There are only two options, straighten it or replace it. The choice is yours. If it were me I'd opt for the new lead screw. There are machinne shops that are equiped to straighten them. You will have to look around.

"Billy G" :))
 
by auto feed i meant that its feeding left to right or right to left. not in or out, i havent really played with that function yet. do you guys know of anyone or any machine shops that can make a new lead screw for me?
 
Here is what I would do, I take it off put it between centers and fine the high spot with a Dial Indicator. The if you have a torch heat a small circle on the high spot then cool it with water.

Don't heat all way around just where the highest place is. Repeat if you need to.

Paul
 
No matter which feed is engaged Dan, right to left or in and out you should not be able to engage the half nuts. I will see if I can locate anyone near you.

"Billy G" :thinking:
 
hmmm ok. i thought the half nuts were the parts that engaged the lead screw to do the left to right feed. but as i said im a noob in this area. not arguing with you just trying to learn.
 
i sent the seller a question asking for all specs. thanks again for the help. i will let you know if this will work for me or not.
 
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