# tails stock alignment



## REO (Sep 20, 2012)

what is all the fuss about tail stock alignment? Often when a question is asked about whether a particular lathe is a good choice or not a poster will make a statement concerning center alignment. I can understand fairly precise alignment being important on several tools and the included problems if they are not.

Table saw blade misalignment with the fence or miter slot pretty common shortfall and predictable troubles.
Although I do not have or use a jointer I have set them up for others and understand what effect maladjustment can have on these machines.
Mills ,Drills and metal working lathes all cases I can understand.

Has anyone actually had trouble caused by misaligned centers or are troubles more imagined than real.


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## 2leggedtermite (Dec 30, 2012)

In a rush to start turning on a "new to me" lathe I didn't check alignment.
Turned a spindle between centres, then turned a tenon on the tail stock end.
Reversed it, chucked the tenon & it was way out of true. Had to re-turn it.

After aligning it was all good with no more hassle.

HTH
Col


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## JollyGreen67 (Nov 1, 2010)

i.e., What 2legged says. If the dead and live centers are not aligned point-to-point, and it's required that the piece be turned around for some reason, it will wobble.


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## wormil (Nov 19, 2011)

Well it's an easy thing to check and if they don't line up I'd start looking for a reason why. Besides the reason above, it could cause the live center to wallow out it's divot and introduce vibration. And if the tailstock is above or below the headstock then your piece won't be spinning coplanar to the tool rest.


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## REO (Sep 20, 2012)

Guys you are turning between centers! two points where the straight line between those points is the axial center of the work piece. the distance from that line is the diameter of the work piece at that point. If you cant create a concentric piece its NOT the misalignment of the tail stock. being a little off on the tool rest is adapted to by the operator as cuts are made I have never seen anyone exactly adjust their wood lathe center that precisely it is adjusted to the point that the operator wishes to use it.

I am honestly looking for an answer to why alignment is a problem. it is used as a reason for not getting certain brands of lathes. why? I have been turning for a long time. I have built a few lathes as well. I have had people complain and bring parts of their machines to me to fix because they thought there was a problem with the machine. One fellow brought a hammer to me to grind the face flat and parallel with the axis of the handle. After trying to explain why the crown on the face of the hammer was by design he still insisted. I ground the face of the hammer for him. you can imagine the trouble he had trying to drive common nails! Even on some of the cheapest machines out there I have found most of the time it is an operator problem not the machine. On a typical lathe built for metal the problem you get with with centers being out of line is a taper on your turning whether they are out of line front to back or up and down. The reason. The ways are not parallel with the line between the centers of the lathe. The cutter is fixed to run in a line parallel to the ways. On a wood lathe the ways of the lathe do not control the distance of the cutting tool from the axial center of the work piece the operator does.

What trouble can be attributed to the centers being out of line.


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## Nubsnstubs (Aug 30, 2013)

Reo, alignment is not a problem. It's misalignment is the problem.

Here is what I've experienced. If your tailstock is off a few thousand's, it not an issue. But, if it's off by 1/16", when you turn a tenon, shape your form, and then turn it around to hog out the inside without truing up the outside, you are going to have an offset on the thickness. The wall thickness could be 1/4" on one side, and 180° away, it should be 3/8" thick. That is if my calculations are correct. It's like doing off axis turnings all the time without wanting to do so. 
I had that problem once and all my forms had thick and thin walls which I felt was a problem. When I solved that issue, my turnings got better, and the only times I get inconsistant wall thickness now is when the wood moves…. 
Correct me if I'm wrong as I don't like giving out false information…........ Jerry (in Tucson)


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## REO (Sep 20, 2012)

This is exactly where I feel there is a flaw in thinking please refer to my previous post. We turn on centers. what you describe could not be from a misalignment of the two centers but a poor center itself! regardless of whether the centers at opposite ends are off or not the turning will be concentric with that center. when the turning is flipped it will still be concentric with the center mark. unless the center itself is not concentric with the spindle on the lathe or the bearing on the tail stock center. If you use a dead center there is no way that it being off center could create an eccentric turning.


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## PaulDoug (Sep 26, 2013)

I would think it is important in a smaller object such as turning a blank for a pen. You have a brass tube in the blank and are going to have a very thin amount of material over that tube when turned down to fit the hardware. You want everything to line up with the center of that tube.


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## wormil (Nov 19, 2011)

A small misalignment is probably not an issue. But even though you are turning on centers, they are not gimbals and will want to spin the piece in the same plane. Sometimes I use my tailstock with a chuck and from experience if the live center is not coplanar with the chuck it will definitely cause problems. At a minimum the center will wallow out the tailstock end and introduce vibration or worse it will move off center and the workpiece won't be round (I had this happen when I got in a hurry and my tailstock didn't seat flat on the ways).

BTW, if anyone wants to test how well their lathe is setup, turn a spinning top.


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## Wildwood (Jul 22, 2012)

REO, guess you have not turned or worked on lathes with swiveling or sliding headstocks. Need to check after moving every time!

One cause given for out of round pen blanks (barrels) is bad head/tailstock alignment.

On my lathe Jet 1642, (sliding headstock) and others like it, beds do flex some before and during operation according to a Jet Technician. A technician told one owner to take his lathe off level to get alignment. It worked for him.

Now if want to discuss alignment with tailstock moved away from the headstock agree somewhat with REO. Not sure how accurately head/tailstock is aligned or how check. Guess could do it using a laser pointer.

Checking head/tailstock alignment on a wood lathe can tip us off to poor castings & poor fabrication, or worn components in those to items and perhaps problems along lathe ways. So whether buying new or used lathe worth few minutes of your time to check head/tailstock alignment among other things.

We are already working a material (wood) that contribute to unbalanced conditions due to density, porosity, moisture content and other factors, so if no other reason check alignment for peace of mind.


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## REO (Sep 20, 2012)

Wildwood your guess would be a Long ways from accurate! Ive been turning for oh…46 years(production turner, started when I was seven years old). I have turned, set up, or worked on most everything out there when it comes to woodworking equipment. I learned from my dad nicknamed Doc because he could figure out troubles that even factory techs couldn't find. I am not claiming to be the end all and be all for lathes. there is a lot of hypothesis and conjecture about what the condition will cause. As Wildwood alluded to the problem if any would become more apparent with a short large diameter piece. on a metal lathe one of the ways a taper is turned on purpose is to offset the tail stock and chuck between centers. the part is still and always will be concentric just tapered. if you have the ability to check many will find that the tail stock quill is not on the same axis as the headstock. It will line up when in one position of extension but not at others most are pretty good but I have seen some real winners. I have heard the out of round because of misaligned centers excuse before. The mechanical physics of a lathe make this assumption impossible. Technique I believe would be found to be the culprit.

Rick I have been addressing turning between centers backing up a faceplate or chuck mounted piece with an off center tail stock is an entirely different matter but it can be handled.


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## wormil (Nov 19, 2011)

I understand the geometry, 2 points define a line. A point only has location, no width, height or orientation. A line is 2 points, a plane is the intersection of 2 lines. But lathe centers are not points they are 2 mechanical centers designed to operate in the same plane. In practical terms a small difference may make no difference but at some point the misalignment is going to affect how well the centers perform and how you interact with the material.


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## Wildwood (Jul 22, 2012)

From the top & sides these bells appear round, looking at their bottoms guess not so much! Was it a naughty head or tailstock?


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## Wildwood (Jul 22, 2012)

OOPS, another production turner and his lathe!

Looks like his alignment spot on!

http://www.wimp.com/footpowered/


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## JollyGreen67 (Nov 1, 2010)

REO, I check my centers all the time to make sure the points meet point-to-point. Not just up and over, or side to side, because that's the way I want them to be! I know for a fact if the dead and live points do not meet, the object WILL wobble when turned 180, which is not acceptable to me, no matter how many years a person has been turning - in my case in the neighbor hood of 57 years, give or take.


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## REO (Sep 20, 2012)

ok so tell me why dont just tell me it does


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## JollyGreen67 (Nov 1, 2010)

Tell you why what?


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## TheDane (May 15, 2008)

On spindles it may not make much difference. On bowls, vessels, etc. it can be a big problem.

On a lathe where the live and tail centers are a 1/16" off, put a blank between centers and make it round, then turn a tenon on the tailstock end. Turn the piece around and mount it in a scroll chuck. The chances of being dead-on center will be about 1 in 360. If you hollow the vessel out you'll wind up with the uneven thickness walls.


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## JollyGreen67 (Nov 1, 2010)

Thanks Gerry - the words I wanted to release from my synapses were stuck in the "mud".


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## Wildwood (Jul 22, 2012)

Even wood lathes have industry standards. Why settle for shoddy made lathe at today's prices. On a used lathe might be able to bring lathe back in factory specs.

You want good head/tailstock alignment whatever you like to turn. Somebody already mentioned reverse turning a spindle blank, it goes for reverse turning anything on a wood lathe. What about drilling on a lathe with drill chuck mounted in tailstock?

I did some production spindle turning several years ago speed & accuracy only requirement. Owner constantly checked those old machines for run out and other problems before any job big or small.


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## REO (Sep 20, 2012)

runnout is measured several ways one is cyclic runout. the other is longitudinal. wildwood I cant tell for sure why your turnings turned out the way they did. I can tell you that the same result will occur if a piece is not sufficiently dry before finishing. I have a customer that wants this look in "birds nests" that I make for him. I ask why because no one so far has explained why they feel their problems are linked to centers being out of line. the responses only express that it happened and that they feel that this is the cause. the center defines the center of the turning it doesn't matter what end. if you turn a spindle around and it doesn't run concentric it is not because the two centers are not aligned it would be because the center has runout of its own. if you chuck up a piece in a lathe where the chuck has cyclic runout and turn the piece the piece you turn will not be off center it will be exactly centered even though your blank may not be. you create a multi axis turning by varying the center line of the turning not by varying the center line of the lathe. drilling? interesting for wood turners the reason most often for drilling is to remove material faster and to prepare for removing more material not a perfectly aligned hole. I did not say all the time I did not say that there werent incidences where it was not. I would like to see a cylinder made on a wood lathe 10 inches long drilled from end to end and see what you fellows get for results end to end. try it. I can get spot on with my tailstock set off over 1/4"! with orders of 3000-5000spear fishing handles a year for a twenty five year span I got pretty good. this post is becoming an ego battle ground, not what I intended. Ultimately I wanted people to think. there are lots of people who think that something causes a problem. they believe that they have proof because of an experience they have had. I asked not why you thought that but why it caused your trouble. Wildwood you seem especially interested in putting me in my place. tell me where that is. Have I made a claim that you feel is in error? production turning is beneath you or takes less talent than the turning that you do?


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## JollyGreen67 (Nov 1, 2010)

REO - I gather you are expressing some kind of frustration with the answers given. Al I know is what I have tried to explain what happens to me during my experiences with a lathe, of which there have been quite a few. Not just the ones I have owned, or the several different name brands I turned in school, or the several name brands I have used during our turning sessions, and during state fair turning exhibitions. And, as for green wood, yes you are correct about run-out, which is and can be expected. Because of the very nature of wood, be it dry or green, it will move no matter what kind of cyclic doohikee problems a chuck has. The ego problem that is becoming clear is the, "My tailstock . . . . . . . . . . . of 3000-5000 spear fishing handles . . . . . . . . pretty good". Is this to mean that someone here does not have a problem, and their production applications are far superior than others ? Is my ego inflated because I have been awarded two best of shows, and numerous first places at a state fair? I think not, as I only try to do the damn best I can, and if that doesn't work so be it.


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## REO (Sep 20, 2012)

Jimbo I was not trying to brag. I was trying to make it clear that I am not new to turning or equipment. I have no best of anything. I havent been in any competitions or trained people how to turn. I am a nuts and bolts hacker far from an artist that was and still am looking for WHY an out of line center would cause an oval turning or off center turning. There have been plenty of those who have said that it does but no explanation as to why. I have not had any of the accompnying troubles with centers that were off. I have never considered there to be any trouble until I started frequenting turning forums and ran into posts stating that there was. Apparently I have been unclear as to what I was asking. I can think of no other way to ask or rephrase the question.It doesent happen on a metal lathe the principals I would think apply to both. Terribly sorry to have even asked at this point.


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## wormil (Nov 19, 2011)

Reo, I've seen the video of your lathe and it's impressive but most of us don't have that. Both my lathes together probably weigh less than the tailstock of your lathe. It's guaranteed you won't drill a straight hole on my lathe with the centers offset. Some of us need all the advantages we can get starting with centers that will align.


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## Wildwood (Jul 22, 2012)

REO, you started a discussion that is debated or discussed by both machinist and woodturners every day. Ego, has nothing to do with my responses here so won't waste time repeating what have already said. 
you are not the only person in this discussion have agreed with.

On a personal level yes, wish you would put your pearls of wisdom in more paragraphs, vice lumping everything together.

We both know many metal or machinist lathes where can adjust headstock or tailstock or both to bring into or out of alignment depending upon task to perform. Even on metal lathes with no adjustments, you still check other parts and or accessories for wear & accuracy and repair or replace for better alignment.

A simple alignment check just one of many procedures turners should learn to do before buying used or ASAP after buying a new lathe. Can also help you ID problems with accessories like faceplates, spur centers, & chucks!

http://jlrodgers.com/pdf/lathe_alignment.pdf


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## JollyGreen67 (Nov 1, 2010)

REO, After running all this through my block head, I can now understand what you were asking. From the stand point of a metal lathe, it makes sense, as I believe they would have to be absolute in precision for anything turned in metal. So I can mow understand as to the WHY? that you are asking about of the point-to-point alignment, in particular a wood lathe. To be absolute in roundness of wood, with the possible exception of boxes, is not remotely possible, due to it's nature. So maybe our talking "points" are relative.


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## REO (Sep 20, 2012)

ok for those of who may have an interest in this. I would be happy to video an experiment documenting the effects of misaligned centers. It wold also qualify the reason for my question. In order to provide accurate information the set up has to be appropriate. It has been said that if I turn between centers and then turn a tenon(I assume that this is referring to the area used to chuck when the piece is reversed in the lathe) on the part and then reverse it and chuck on the tenon there will be a problem. I want to be sure that I am working on a scale that is applicable. what Diameter would be appropriate? what length? please keep it reasonable. I am open to parameters. I am able to easily shift my tail stock 1/2" out of alignment. I think that this should be sufficient for purposes here.

I have checked my scroll chuck it has a TIR of .010" 
In my case I chuck a drive center in the chuck to turn between centers because it headstock on this lathe is not bored for MT adapters.
Mounted in the chuck the drive also reflects the .010" runout 1/2" of offset should far outweigh misleading information from the drive center being off.
The headstock is parallel with the ways mine is capable of rotating 360 degrees with positive stops at 45 deg increments.
The tail stock until it is shifted is in line with the ways.
Is there anything else I am not accounting for?
Looking forward to your input!

Roger


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## TheDane (May 15, 2008)

Roger-Sounds like a plan. I had thought about doing this, but my lathe is dead-on and I come for the "if it ain't broke, don't fix it" school.

I would think a 4" diameter billet 8" or 10" in length should be enough.

Bring the billet to round, then put a tenon on the tailstock end suitable in diameter for a good fit in your scroll chuck. When you make the tenon give it a generous enough shoulder to allow it to seat firmly against the chuck jaws.

Turn the blank around and mount in your scroll chuck with the tenon shoulder seated firmly against the jaws.

Bring your tailstock close to but not touching the billet, and see how close to center you are.


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## REO (Sep 20, 2012)

Dane I know I will be off the amount that i have offset the tailstock. This is the point is where the off center turning is created? Continuing from this point will create an off balanced wall? I'll have to glue one up unless you will accept a piece of UHMW to stand in for the block of wood.


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## TheDane (May 15, 2008)

Any material should work …


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## Bluepine38 (Dec 14, 2009)

The main reason I have found to get the headstock and tail stock in line is that I have drill chucks for both
the headstock and the tailstock. Try drilling an accurate on center hole through a wood turning that you
made on a lathe that did not have the headstock and tailstock aligned. It happened a few years ago and
I might have uttered a few adjectives other than, Oh Darn!


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## REO (Sep 20, 2012)

Hey Folks finally back. Its was cold in the shop! I couldn't convince my wife to come out and do a video but since doing this I did get a tripod for the camera. I am no photographer and I hope what I am trying to show comes across clearly with the combination of fuzzy pictures and written explanation.

For some reading this the information may be old hat, for some it may answer some questions or help to understand if you are having trouble as a result of centers that are not aligned properly or something else. Maybe it will save someone some frustration in the future.

What is the reason that any one of us has invested in a lathe? What makes it useful? Simply answered we are not squares! In most drawing programs if it is possible to draw a turning it is done by drawing a path and then revolving that path around an axis. Lathes are designed to bring that drawing to life in the real world. Lathes cut a concentric path around an axis. The path may be comprised of many different diameters but at any given point along the length of the turning if you were to cut it perpendicular to the axis, put the end down on a piece of paper trace around it you would have a circle. In a metal lathe there are ridged constraints built into the apron cross feed and compound that can make it extremely accurate. In turning wood for most of us these constraints have been removed and we are free to adjust the form of the material without restriction. This also allows more interaction with the material which in most cases is the point. Of course there are interactions that are not planned! explosions, implosions, catches, material defects and the interaction of skin on wood in whatever form.

I am going to throw you a curve here so hang on a bit. To make a turning I need concentric paths around an axis. so to start out I need to define what an axis is. An axis is defined as "A straight line about which a body or geometric object rotates or may be conceived to rotate." We all remember from math class that a line is defined as two points. Here is the catch. When working on the lathe there are at least two axis and sometimes three or four in play! Here they are: number one is the axis through the headstock bearings. Number two is through the turning itself. Number three is through the bearing on the tail stock. 
of course if you wish you could complicate this and say that there is an additional axis through the drive center. If these are offset it will affect the virtual center but not the actual center of the piece being turned. You can experiment with this a couple ways. The easiest is shimming one of the jaws in your chuck. Obtain a piece that you will feel comfortable turning in the jaws of the chuck but without the tail stock. Place it in the jaws of the chuck with a piece of wood between ONE jaw and the workpiece. This will force the center of the workpiece off of the center of the headstock. Now turn two steps in the piece leaving a section unturned. Stop the lathe and check it out. You will have two rings concentric with the axis of the bearings in your headstock and one that is eccentric. No matter what you do the axis of the turning will be coincident with the axis of the headstock of the lathe. Where does the fault lie? Of course its my fault I told you to do it! I am sure that all of you could figure this out just from experience. my point was to set a foundation to build on and get you thinking about the actual mechanics. Oh yeah number four would be the axis formed by all points equidistant from the controlling edge of the ways (on metal lathes).

Using a chuck to hold the material the axis of what you are turning will ALWAYS be coincident with the axis of the headstock. If you re-chuck a part and do not get the axis coincident you will have a multi axis turning but the axis of what you ARE turning will be coincident with the axis of the headstock of the lathe.

Coincident or convergent/intersecting axis. What or is there a difference. The ideal alignment of a lathe would place the axis of the headstock bearings and the tail stock bearings coincident to the same line. By default the axis of the work piece would then be coincident to both. In many lathes (metalworking) in addition the axis formed by a line equidistant from the ways of the bed is also desired to be coincident with the rest. In all lathes there are shortcomings in one place or another. Some fall way off the mark and some are not bad. What is acceptable and what is not is determined by the use of the machine.

When I push the tail stock up close to the headstock and adjust the centers until they are in the same axis at that point I have not established coincident axis. I have established that the axis will intersect or converge at that point. The headstock the tail stock or both could be skewed such that this is the only place that they will align. No matter how hard you work at it there will always be some degree of misalignment. The question is what will happen if I don't get it perfect? Well? What is the purpose of a lathe? To turn on an axis. what establishes an axis? A line. What defines a line? Two points. So I can use the headstock as we did previously and we will for sure have coincident axis. Problem: how do I get it in the chuck? What did you do before? Marked centers turned it round turned a tenon on the tail stock end then flipped it and chucked it up. I didn't have to tell you that. Same thing as I did with a piece of UHMW, but I purposely set the centers off.








marked my centers.
turned it round.
flipped it and chucked it up!

__
Sensitive content, not recommended for those under 18
Show Content









As the picture shows the tail stock is off center!








If you can see it I ran the tail stock in and made a mark then highlighted it with a blue marker.
The red lines were drawn with a marker in the lathe with it running chucked up but not with the tail stock engaged. They are concentric with the axis of the turned part. If i turned at this point I would have an even wall all around. if i used the tailstock to prove my center and tightened the chuck then removed my tailstock it would have made eccentric rings and if turned would have been varying thickness walls. That is not the lathes fault! I would have set the turning up incorrectly for the lathe to do its job!
If If i had forced the turning over to the tail stock center and then tried to turn it would not have been a good deal. The chuck trying to rigidly hold the work axis in line with the headstock axis while the tail stock was trying to move that axis off center through every revolution. Would have been hard on the chuck at least.
This causes lots of faceplate failures! The faceplate isn't set up perpendicular to the axis of the piece and the tail stock is used for support. fatigue from flexing finally does them in. So what If I need to support the work further along in the process? A ring steady would be a good choice or go back between centers. 
Am I all wet? Did this help or make it worse? I had to rush at the end to get ready for work but i wanted to get this off.


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## TheDane (May 15, 2008)

Roger-Very interesting … you put a lot of effort into this test.

Makes a good argument for the use of steady-rest type devices.

Thanks!


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## RolfBe (Jun 7, 2013)

Another concern regarding tail stock Misalignment. If you put a piece of say, hard maple in your chuck, long enough to need tailstock support. as it spins there is a defined center at the end. If the tail stock is off (out of alignment) then you are trying to move that center point. the cylinder will be forced to try and move in the chuck or flex (which it cant easily do) it is trying to act like a universal joint. If it is between centers then there is more freedom of movement and it isn't as big an issue. On a metal lathe we used to do this deliberately and use a lathe dog to hold the material real useful for turning tapers.


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## wormil (Nov 19, 2011)

Thanks Reo and others, given me a lot to think about.


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## JoeLyddon (Apr 22, 2007)

*I didn't do it…   *

.

.

Very interesting…

If you put pointed bits in each end… and brought them together to meet… and adjusted Point MEETS Point, would that do it?

*Merry Christmas and
Happy New Year!
*


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## REO (Sep 20, 2012)

not necessarily joe. originally my POINT lol was that when turning between centers there is little need for concern to have the points aligned. this quickly grew into a discussion about misaligned centers causing off center turnings and how. I did not have the time to completely cover the subject but though the points may come together at that one point several factors come into play where that simple test may not truly mean your lathe is "in line". for instance you can have the same result as the tailstock out of line experiment when the headstock is not square to the bed or the tailstock is skewed and the points will line up at one given location.


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## JollyGreen67 (Nov 1, 2010)

Now, my headache is even more advanced than prior to what it was before. ))


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