I'm driving myself insane. I have a Delta Midi, with 3 different chucks (all cheap-o's): a regular PSI 3-Jaw, a PSI Mini, and a Jacobs thingy. I know the Mini (brand new today) & Jacobs turn perfect, as when I stick my Mandrels in there (brand new 2 days ago) - 3 out of the 4 turn perfectly smooth (not from Lamar).

I take my tail stock, with live center (time for a new one of those) - and slide it all the way into the jaws to ensure they are perfectly aligned. Tehy are, teh center touches teh teeny tiny opening in teh jaws when they are closed shut. I stick teh mandrels in there, turn the lath on, perfectly smooth - BUT when I put my tail stock uo to it, it's off. IT's perfectly in teh middle looking from teh front, but when I look over it I can see the center is not 100% dead center - it's off by enough to make my post this.

Is there any way I can fix this, or is this the product of a cheap lathe? I really think when I'm using my 18" Mandrels on HIGH speed, this small differnce causes severe vibration, and has ruined 2 sets of 3-jaw chucks on me, & I'm not using it NEARLY as much as I should.

Any clues, tips or watever, would be greatly appreciated. Thanx

Billy, at any time has the lathe been knocked over or droped, wondering whether the base (bed) has a slight bend or warp in it compared to near the headstock, just a thought. You probably already thought of it anyway.

Fortunately not, that thing is far too heavy to drop on the floor - the foundation to my hous emight crack if it did, forget teh bed being mis-aligned, lol.

I think when I tighten teh tailstock assembly it makes teh center move a little off. I'm still trying to figure out EACTLY what teh heck is causing this.

Unlikely you'll bend cast iron. If you can run the tailstock with live center up the closed jaws of your chuck, and they meet perfectly, then the lathe is okay.

Now if you insert a mandrel into the chuck and tighten down, and then the tailstock with live center won't match up to the machine inset in the other end of the mandrel, you may or may not have a problem. First off, your mandrel may not be as straight as you think. Another thing to remember is that you don't want to chuck the mandrel down tight in the chuck and then run your tailstock up. Put the mandrel in the chuck and only tighten the jaws to the point where they lightly touch the mandrel. Now run the tailstock up and put the live center in the machined end of the mandrel. Now go back and tighten the chuck. Now run the tailstock out until snugly seated in the mandrel. All should be well.

If you tighten the mandrel in the chuck, it can be put off by just a degree or two, which over the length of many inches makes it look like something on the lathe isn't aligned.

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Try this, chuck a piece of wood into the headstock chuck. Move the tailstock up to the wood face until the live center tip just touches the wood. Lock it down. Now rotate the headstock and tell us what pattern the live center tip leaves on the wood. A point or a circle? If a circle, how large in diameter?


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BILLY,

Most lathes are adjustable, this is how you make turning with a tapper to them.
The base of the tail stock should be adjustable left & right , if no adjustment, you will need to shim the " ways "
what the tail stock slides on, which is the base, try to find a shop that might let you look at their lathe, wod or metal
all tail stocks need to be adjustable to compensate for wear. I could get in to it in more detail. But you need to look at your lathe carefully, then we can talk.

Dave , Pearl River Rods, PRRODS@aol.coM

PRRODS also means STREET RODS, I do both metal work and wood work

Tom, cast iron now days isn't what it use to be, more like cast steel. Too many alloys being added due to recycling of iron and steel.

Wood lathes such as the Delta Midi do not have adjustable tailstocks or bed ways, as far as I know. Keep in mind these are $300 lathes at about retail. Work backwards through the distribution channels and you have what amounts to a $45 lathe when it comes off the manufacturer's end.

However, they are pretty good lathes, really. Alignment of headstock and tailstock is usually fairly close but there are places where this can go wrong. The headstock itself is fastened to the bed with allen screws. It may or may not be pinned for alignment - I haven't had one apart.

If Billy can do the test outlined with the block of wood and let us know what shape the live center scribes on the wood, it will be a lot easier to figure out what's actually out of whack here.


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My midi-lathe is off on the alignment of the head and tailstock by about 1mm. Doesn't seem to harm the wood work I do, but I'm not a real craftsman by any means.

I did learn the hard way that you don't tighten the chuck until after the mandrel end has been located in the tailstock live center.

I've noticed that my Delta's tailstock has a little wobble left-right when not tightened down. So if I want to have the two centers lined up, I need to hold it to the left and then tighten it. Haven't come up with any other work around for this...
==dave==

First - Thanks for all teh answers. THat's one benefit of the internet. THE other is it motivates you to figure out what is wrong because you want to do all you can to stop making buffoon posts, lol.

HEre is the problem, and how I corrected it:

I have 3 different sized Mandrels, 9, 14 & 18". I noticed the longer the Mandrel, the further off the tail center was. Hmmm? I actually LOOKED at teh Headstock assembly, and noticed there were 4 HEx bolts attaching it to teh bed. DUH! I loosened them all up, cuched up a Mandrel, and made sure it aligned with teh tail stock. RE-tightened the hex bolts, and hung my head in shame for posting this question.

Basically, the headstock did not point striaght down the center of the bed. Once I made this adjustment, everything was just fine. I was concentrating on teh tailstock because I was not aware teh headstock could be off...until I looked. For those who are not aware, bolts can be tightened & loosened. Just because the lathe came with everything attached, doesn't mean you can't "fix" it.

THanks again, I appreciate it.

Now, this is good stuff.

I just got Andy's DVD and i didn't notice any suggestion about not tightening the chuck until the tailstock is snug. I will remember this.

I have 17" mandrels from Andy and noticed that the thinner ones (1/4 and 3/16) will flex in the middle. I try to use the thicker ones to prevent any off-center results. If I do use the smaller sizes I mount the grip near the end instead of the middle if possible. I've turned several grips already and have had zero problems with my new Turncrafter Pro from PSI.

Terry

Terry, you might be able to push the mandrel thru the head stock before you tighten the chuck so that you only have 5 or 6 inches between the chuck and the tail center. hope your Turncrafter Pro lets you do that? The Jet does. That gets rid of alot of the flex and corresponding tool chatter. Also, I think Andy will make shorter mandrels if you ask?

This is why I mentioned the thing about the headstock being affixed with those allen head bolts. I'm surprised that the headstock unit isn't "pinned" for alignment, but in your case I guess it's better that it's not. Glad you got it trued up.

There is a special alignment tool offered by various woodworking shops (Packard Woodworks for one) that is basically a double morse taper shaft. You loosen the headstock and tailstock and run the tailstock up with the alignment tool between the two (no chucks or live centers to thrown anything off). As you push the tailstock into the headstock the morse taper tool moves them into alignment and you lock everything down there (the headstock).

On a Delta or similar that does not have a pinned headstock and can be adjusted, this is surely an invaluable tool to have.

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William,
You said "I did learn the hard way that you don't tighten the chuck until after the mandrel end has been located in the tailstock live center."

I am not sure I understand why this is an issue? I ALwAYS put the mandrel in the chuck, tighten the jaws first, then run the live center into the counterbore last....could you elaborate on the why's of this?

Andy Dear
Lamar Manf.

I just watched this chapter on Andy's DVD again.

He clearly tightens the chuck first, then snugs the tail stock. I'll be interested to see where this discussion goes.

The Turncrafter Pro does allow for sliding the mandrel through the head, but the chuck I have (std 3-jaw from PSI) is solid at the face. I'm positive Andy would sell me shorter mandrels. If I get into reel seats, this will be mandatory. For now, I'll just use the larger sizes where I can. It's all turned out well so far.

Terry

If your chuck jaws are not perfect or you have tape on the mandrel that would make it less than perfectly centered, it throws off the end of the mandrel and can cause it to bow when you run the tailstock in.

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