Question about having a straight mandrel

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angboy

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I have seen people describe on here that sometimes if your mandrel isn't straight that will mess up your pen. I remember people sometimes commenting that a pen would look like the mandrel wasn't quite straight if the pen wasn't completely symmetrical all of the way around, or if the blank seemed higher on one side of a bushing than the other.

When I put my mandrel in the headstock and push the tailstock up to the end of the mandrel, the tailstock doens't line up exactly right. I have to move the end of the mandrel a little bit to get it to sit inside the point of the tailstock. I have checked to be sure that the headstock and tailstock are aligned by putting the pointy thing in the headstock end and bringing them together and they meet perfectly. So that suggests to me that the mandrel isn't perfectly straight.

I got a new mandrel to see if that solved the problem and it still seems to work the same way, with the mandrel not lining up perfectly straight. So I'm wondering if there's something else I need to look at? I haven't really noticed that my pens seem lopsided, it just bugs me when I push the tailstock over, since I'd read how important it was for the alignment to be exact. Are mandrels that exact and precise? That would seem to me to be a lot to ask of a $10 or so thing.

Also, it would seem to me like when I do move the mandrel over a little bit until it sits on the tailstock pokey thing, that that would align things correctly. Am I wrong about that?

Thanks very much!
 
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Have you put the mandrel in and rotated the handwheel to see if the end of the mandrel wobbles as it rotates?
You may want to invest in an alignment tool- http://tinyurl.com/9wq34
You shouldn't have to align the mandrel to the live center by hand, but you already know that. I can't think of another reason unless you have a lot of slop in your spindle bearings but I think you'd have noticed that also. Good luck and let us know if yo find anything.
 
You say the head and tail stock are aligned. What is your mandrel chucked in. A morse taper could have the hole centered but drilled at a slight angle. A chuck could have one jaw slightly off, same with a drill chuck.
 
Thanks for the tips everybody. Frank, I had checked about the lining up of the headstock and the tailstock- I probably didn't make that so evident with my description, since I couldn't remember the technical name of the live center and spur![:I]

They do seem to line up fine. I printed out the article from Russ and I'll try those things tonight and see if I can figure it out. But I will also try lining up the head and tailstock again just to be sure they are in line!

When I first got the lathe, they didn't line up. When I called Jet for help with that, the person kept trying to tell me to move some part that I kept telling him just wasn't on my lathe. He got kind of irritated with me and kept telling me it was there. Anyway, he finally realized he was wrong when he asked again what model lathe I have. Since mine does have the headstock that will move, he pointed out that as long as the misalignment was left to right, then I could move the deadstock left to right.

I haven't moved the headstock recently, but I should probably check that again. I had a mishap the other night when I broke my parting tool and things went flying, with part of the parting tool making it around the open door and halfway down the next room somehow, so that certainly could have messed up the alignment of things!
 
Jim- I use the Morse taper. I actually have two, but your post made me realize I should check and see if this happens with each fo them or only one.
 
Originally posted by angboy
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I haven't moved the headstock recently, but I should probably check that again. I had a mishap the other night when I broke my parting tool and things went flying, with part of the parting tool making it around the open door and halfway down the next room somehow, so that certainly could have messed up the alignment of things!
Click to expand...

Bingo! Betcha that is it[;)]
 
Originally posted by angboy
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I haven't moved the headstock recently, but I should probably check that again. I had a mishap the other night when I broke my parting tool and things went flying, with part of the parting tool making it around the open door and halfway down the next room somehow, so that certainly could have messed up the alignment of things!
Click to expand...

You broke your parting tool? Sort of gives me a whole new perspective on the term, "Iron Wood".[:)]
 
It wasn't a fun experience that's for sure! I was trying to part of a bowl I was making. The wood I had used the put on the back of the bowl to attach to the faceplate was VERY hard wood. I don't know what kind it was, but even when we went to saw it off the back of the bowl, it was an effort for the saw to get through it. So I think I must have kit the parting tool on that hard wood and it went flying. The only part that remained was the wooden handle that stayed in my hand. I still haven't found all the pieces yet!

Anyway, I did check and the head and tail stocks were a little bit misalgined, so when I adjusted that, it made the mandrel a little better. But it's still not perfect, so I'll just have to keep trying. I'm wanting them absolutely perfectly lined up, and it's only a very small amount that I'm having to move the mandrel. The live center (I've remembered what's it's called now!) is almost inside the end of the mandrel, it just isn't going exactly into the deep center of the mandrel, but it's not like I have to move the mandrel so that the live center goes over the edge of the outer circle of the mandrel to get it seated right (hope that makes sense!). So I wonder if I'm expecting too much?
 
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