Turning Question

Thanks for all of the great ways to check. I will try today with a dial indicator. The first cuts cut equally all the way, other than the fact I was a little off centre on the tailstock end. I welded 4 nuts to a piece of plate and put that to the inside and then tacked the pipe to the plate. I sharpened the tool for the last pass. It took all afternoon to make three passes on 48". I cleaned the ways after each pass and put more way oil on.
Could it have been backlash in the cross slide? I had chips on the first passes, but the third pass I was getting long cuttings coming off. I had a long handled hook that I was pulling them back and it felt like the cross slide pulled back, but not sure. That's when it stopped cutting.
 
Tozguy said:
If both lathe wear and work deflection are at play, then it would easily explain a difference of .007'' over 24'' (.015'' on diameter).
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:+1: Yup, that's my guess. And some tool wear.
 
Found the problem, I am embarrassed to say I didn't tighten the tool bit up after I sharpened it. When I started cutting at the one end it cut for about a foot and then stopped. I then backed it out and changed it to start from the other end. The same thing happened.
So this morning I went out and started measuring with a dial indicator and thought that's weird. Then I checked to make sure everything was tight and the tool was loose:faint:. Rookie mistake. Made one more pass and it cut evenly the whole way.:encourage:
 
Good on you Martin for finding the cause. If you ever find a way to never forget/overlook anything please let me know.
 
Martin W said:
Found the problem, I am embarrassed to say I didn't tighten the tool bit up after I sharpened it. When I started cutting at the one end it cut for about a foot and then stopped. I then backed it out and changed it to start from the other end. The same thing happened.
So this morning I went out and started measuring with a dial indicator and thought that's weird. Then I checked to make sure everything was tight and the tool was loose:faint:. Rookie mistake. Made one more pass and it cut evenly the whole way.:encourage:
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I was told many years ago when I was an apprentice that it's never a mistake unless you can't fix it. Learn from it and move on. And glad you found the problem.

Tom S.
 
John Hasler said:
I've done that. I've also failed to lock the toolpost down, forgotten to lock the compound, and not locked the carriage when facing.
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I think I have done all of those mistakes on one cut! 8^) And I don't think any of them have ever ruined the work, making it unusable after correcting the problems. Kick myself in the butt and move on...
 
I didn't see that coming... Well now you know your problem, it's YOU! :D Bet you won't do that again!(Soon anyway.) The good news is your lathe is good!:congratulate:
 
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I'm more likely to make left/right errors, either making both sides the same when something should be reversed for the other side, or assembling something upside down, then flipping it over, then going "oh, right, it was upside down" and then cutting it apart...
 
i had a toolholder not clamped in the qctp
found out after i was done when taking it out
i had actually parted a steel rod with the toolholder not tightened down....
 
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