# Headstock/tailstock alignment



## transatlantic (8 Feb 2021)

I have the Fox lathe (pictured below) that has a rotating headstock, and have noticed an issue. If I move the tailstock close to the headstock to check alignment of centers (a cone shaped live center at each end), all looks good. But if I turn an 8"piece between centers, turn a dovetail on one end, and mount in a chuck. Although it appears to spin perfectly true, the live center in the tail stock will now not align with the dimple created when it was turned between centers. The dimple is about 2.5mm too high.

I've repeated this expeiment many times now, and am convinced that the headstock is pointing/rotating slightly upwards, as shown by the red line. It's hardly noticable when the headstock and tailstock are close togeather, but becomes more apparent as you space them out.







How do I go about solving this? if it was a fixed headstock, I see people just stick in some shims and bolt it down, job done. But as it's a rotating headstock (which I make use of all the time), I can't just shim it. Or if I did shim it, I'd have to glue them or something, to keep them secure. Any ideas?


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## minilathe22 (8 Feb 2021)

That's a tricky one with a swivelling headstock. Perhaps you could use the shims method just to determine how/where the misalignment is? Then braze/solder/glue a shim to the base of the headstock.


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## Phill05 (8 Feb 2021)

If it fine between centres it could be a misalignment of the chuck, just had a mate with a problem like this and it was a build up of dust in the chuck register.


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## Paul Hannaby (8 Feb 2021)

It might be worth checking the bed is straight. I had a similar problem once and the bed was the cause of the issue.

Also, try switching the headstock & tailstock round on the bed to see if it's any better the other way round.


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## Phil Pascoe (8 Feb 2021)

Axminster Woodturning Lathe Alignment Centre - 2MT


This simple tool is a double-ended taper that can be used on any woodturning lathe with a sliding or rotating headstock that has a 2MT spindle and tailstock fittings. Simple to use, just insert the tool firmly into the headstock spindle taper as you...




www.axminstertools.com


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## transatlantic (8 Feb 2021)

minilathe22 said:


> That's a tricky one with a swivelling headstock. Perhaps you could use the shims method just to determine how/where the misalignment is? Then braze/solder/glue a shim to the base of the headstock.



Yep - I'll have to try the shims anyway to see if it even solves the issue.



Phill05 said:


> If it fine between centres it could be a misalignment of the chuck, just had a mate with a problem like this and it was a build up of dust in the chuck register.



It's not the chuck, as I tested it with multiple headstock accessories, including different, chucks, friction drives, Jacobs chuck etc etc. All appear to show the same issue.



Paul Hannaby said:


> It might be worth checking the bed is straight. I had a similar problem once and the bed was the cause of the issue.
> 
> Also, try switching the headstock & tailstock round on the bed to see if it's any better the other way round.



If it's the beds not being flat, then I am well and truly **** 



Phil Pascoe said:


> Axminster Woodturning Lathe Alignment Centre - 2MT
> 
> 
> This simple tool is a double-ended taper that can be used on any woodturning lathe with a sliding or rotating headstock that has a 2MT spindle and tailstock fittings. Simple to use, just insert the tool firmly into the headstock spindle taper as you...
> ...



Not sure how that helps? that is for aligning in the horizontal plane is it not, where there is a lot of play to work with? if I use it in my case, isn't it just going to force something into place and perhaps damage something?


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## Sachakins (8 Feb 2021)

Is it definitely the headstock? Could the tailstock be pointing down, not headstock pointing up?.
I use the MT2 Alignment tool, Great to get centred. Worth trying one out, set it in the headstock first, then use a DTI to check run out along it's length at about 5 points, this will show if headstock is running true. If out it maybe your spindle bearings are worn, and the motor tension on belt is pulling spindle down a tad at back.


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## Sachakins (8 Feb 2021)

Also try to shim end of bed up, if it's floor mounted, maybe something has sank at bit at either end, or if bench mounted, maybe bench has swollen in middle, throwing of level of the bed. If you could borrow a true engineers reference level, try it along the bed.


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## transatlantic (8 Feb 2021)

Sachakins said:


> Is it definitely the headstock? Could the tailstock be pointing down, not headstock pointing up?.
> I use the MT2 Alignment tool, Great to get centred. Worth trying one out, set it in the headstock first, then use a DTI to check run out along it's length at about 5 points, this will show if headstock is running true. If out it maybe your spindle bearings are worn, and the motor tension on belt is pulling spindle down a tad at back.



It seems to get worse the longer the piece you add to the headstock, which is leading me to think the issue is there. But as a previous poster said, could also be the beds


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## Sachakins (8 Feb 2021)

transatlantic said:


> It seems to get worse the longer the piece you add to the headstock, which is leading me to think the issue is there. But as a previous poster said, could also be the beds


Could be rear of bed dipping down slightly, this would get worse the further you get from headstock?


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## Jacob (8 Feb 2021)

Is 2.5mm a prob - what happens if you tap your 8" piece down to fit the tail stock?


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## Phil Pascoe (8 Feb 2021)

transatlantic said:


> Not sure how that helps? that is for aligning in the horizontal plane is it not, where there is a lot of play to work with? if I use it in my case, isn't it just going to force something into place and perhaps damage something?


It would show any deviation so at least you would be 100% sure of the problem, and allow you to check if using shims under the headstock that you have got them right. Line the head and tail stock up with the headstock slightly loose and see if you can get a feeler under the outboard side?


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## Duncan A (8 Feb 2021)

If the lathe spindle extends through the headstock at both ends, measure the centre heights to the lathe bed. If one end is higher, that would indicate a headstock issue. Look at the underside of the headstock and use a straightedge to check for any raised areas - it's possible that there's a very slight edge or protruberance from a knock some time in the past - perhaps when putting it onto the bed.
Duncan


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## transatlantic (8 Feb 2021)

Jacob said:


> Is 2.5mm a prob - what happens if you tap your 8" piece down to fit the tail stock?



The problem is with turned boxes. When I have hollowed out both the lid and the base (both ends still have their dovetail and initial centering dimple), I then fit the lid to the base, and mount the base in the chuck (using the dovetail), and then bring up the tail stock for support. At which point, even though the piece runs perfectly true, the tail stock does not match up to the centering dimple. If I force it, the lid is forced to not be on straight.

Hope that makes sense. But basically I am describing the 21:10 point in the following video. The center point of the lid runs perfectly true, but the point of the tailstock does not align with it.


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## Jester129 (9 Feb 2021)

How about using a laser level on the bed, then somehow set it up on either/both ends? Just a thought. HTH


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## Danieljw (9 Feb 2021)

Most likely to be lathe bed, I would start be checking the bed for level and square.
If it is bolted to the floor, release the bolts and recheck


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## Phil Pascoe (9 Feb 2021)

It may well not be the bed with the misalignment occuring so close to the headstock, it may well be that the spindle isn't parallel to the bed.


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## Jacob (9 Feb 2021)

Phil Pascoe said:


> It may well not be the bed with the misalignment occuring so close to the headstock, it may well be that the spindle isn't parallel to the bed.


And if you shim , trim, adjust the headstock you are probably going to have to do the tailstock too.
Should be easy check the bed - take everything off and squint along it, or shine a focussed torch beam. 2.5mm over 8" should be visible. But the least likely cause at a guess.


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## Paul M (9 Feb 2021)

Hi is this a setup problem. When mounting in the chuck, the tailstock revolving centre should be engaged at same time. Then tighten chuck jaws equally, whilst rotating checking concentricity, lightly tap to correct. Use a DTI or scribing block to check
If you place stock in chuck & tighten up, you have no support at tailstock.
I'm was a mechanical turner (apprentice trained). When we reversed chuck we would do the above, use a DTI to check concentricty (whilst equally tightening the jaws supported with centre) and tap with a plastic mallet to get running true. Hope this helps


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## Phil Pascoe (9 Feb 2021)

Jacob said:


> And if you shim , trim, adjust the headstock you are probably going to have to do the tailstock too.



Why probably? If the fault is in the headstock the quill may well be perfectly parallel.


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## Jacob (9 Feb 2021)

Phil Pascoe said:


> Why probably? If the fault is in the headstock the quill may well be perfectly parallel.


They could end up both being parallel to the bed but at different heights.
PS I'm just being pessimistic - I think it's a set-up prob as PaulM says above.


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## Tris (9 Feb 2021)

Is this a new problem or one that has always been there? 
If it's a new problem I'd start by looking under the headstock for accumulated crud, sawdust and finishes. 
Once that's cleaned up and whilst the headstock is off I'd check the bed is straight and not in wind. Wind probably won't be an issue on this style of bed, more so on parallel bars like record cl lathes. 
If you have a through headstock use a straight metal rod to check the alignment of the head and tail stock along the bed length, if it's still out you may have to file a little off the front of the headstock casting or shim the back edge as described in earlier posts. 
If it has always been a problem you might have an issue with the headstock casting. My jet lathe required a bit of fettling as there was a ridge on the edge of the casting that gave the problem you describe, a light filing sorted it out. 

Hope this helps
Tris


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## transatlantic (9 Feb 2021)

Paul M said:


> Hi is this a setup problem. When mounting in the chuck, the tailstock revolving centre should be engaged at same time. Then tighten chuck jaws equally, whilst rotating checking concentricity, lightly tap to correct. Use a DTI or scribing block to check
> If you place stock in chuck & tighten up, you have no support at tailstock.
> I'm was a mechanical turner (apprentice trained). When we reversed chuck we would do the above, use a DTI to check concentricty (whilst equally tightening the jaws supported with centre) and tap with a plastic mallet to get running true. Hope this helps



When the piece was between centers I added a dovetail so I can secure the ends in a chuck, so if everything is as it should, I should be able to place the wood in the chuck and have no gaps where the end of the jaws meet the side of the dovetail.

If I do as you say, and use the tail stock to align the piece with the center point (from where it was between centers) before tightening the jaws, then it skews the other end in the chuck, and there is now a gap on one side.


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## transatlantic (9 Feb 2021)

Tris said:


> Is this a new problem or one that has always been there?
> If it's a new problem I'd start by looking under the headstock for accumulated crud, sawdust and finishes.
> Once that's cleaned up and whilst the headstock is off I'd check the bed is straight and not in wind. Wind probably won't be an issue on this style of bed, more so on parallel bars like record cl lathes.
> If you have a through headstock use a straight metal rod to check the alignment of the head and tail stock along the bed length, if it's still out you may have to file a little off the front of the headstock casting or shim the back edge as described in earlier posts.
> ...



It may have always been there, not sure. I've basically only started to notice it as I have been doing more and more pieces that aren't simply held between centers, and are long enough (more than 8") for it to be noticeable. I've previously only done bowls.

Last night, I took off the headstock to have a look underneath. It's all clean, no muck or anything that would cause an issue. However, it turns out that it does not rest on the casting of the headstock itself. It rests on what looks like a precision piece of machined steel, which again , is clean of any muck.

I'll take some photos in a bit to show you


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## Phil Pascoe (9 Feb 2021)

Jacob said:


> They could end up both being parallel to the bed but at different heights.
> PS I'm just being pessimistic - I think it's a set-up prob as PaulM says above.





transatlantic said:


> If I move the tailstock close to the headstock to check alignment of centers (a cone shaped live center at each end), all looks good.


The tailstock is probably OK - you'd adjust the headstock to suit? Only one is at "a different height".


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## Jacob (9 Feb 2021)

Phil Pascoe said:


> The tailstock is probably OK - you'd adjust the headstock to suit? Only one is at "a different height".


But it might then be easier to machine the tailstock down to meet the new level of the headstock, rather then shimming the head stock up - unless it is easier to do.I imagine there is no point you could shim - it's swivelling casting straight on to the bed as far as I can see.


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## transatlantic (9 Feb 2021)

Jacob said:


> PS I'm just being pessimistic - I think it's a set-up prob as PaulM says above.



As I said in one of the previous posts, I can reproduce the issue with other accessories in the headstock, such as a Jacobs chuck with a drill bit in it, or a chuck with a machined piece of round bar in it.

Sure, the Jacobs chuck might have error, and the drill bit might have error etc, but visually it runs true, and there is no vibration when you place something on it, and yet still does not align with the tailstock.


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## Jacob (9 Feb 2021)

transatlantic said:


> As I said in one of the previous posts, I can reproduce the issue with other accessories in the headstock, such as a Jacobs chuck with a drill bit in it, or a chuck with a machined piece of round bar in it.
> 
> Sure, the Jacobs chuck might have error, and the drill bit might have error etc, but visually it runs true, and there is no vibration when you place something on it, and yet still does not align with the tailstock.


Right - it's the headstock then!


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## transatlantic (9 Feb 2021)

Here are some pictures of underneath the head stock. There was no muck or dirt. Just oil for lubrication.


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## MusicMan (9 Feb 2021)

The process is
1. Check that your bed is flat and straight. An engineers' quality level (can usually find them secondhand) and straight edge. Check it doesn't have any funny bumps.
2. Mount a lathe reference bar in the headstock, on the Morse taper (nothing else will work). Check that it is parallel to the bed (use the level). If it is not, shim below the headstock support (where it doesn't rotate)
3. Do the tailstock alignment to the headstock at close distance again. It should now work when far away.


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## Tris (9 Feb 2021)

If the bed is true and you turn the ring that sits on the bed bars 180 degrees and clamp the headstock back on it do you then get the axis pointing down (ignore the alignment stops for the moment)?
I think you are chasing an accumulation of small errors here


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## transatlantic (9 Feb 2021)

MusicMan said:


> The process is
> 1. Check that your bed is flat and straight. An engineers' quality level (can usually find them secondhand) and straight edge. Check it doesn't have any funny bumps.
> 2. Mount a lathe reference bar in the headstock, on the Morse taper (nothing else will work). Check that it is parallel to the bed (use the level). If it is not, shim below the headstock support (where it doesn't rotate)
> 3. Do the tailstock alignment to the headstock at close distance again. It should now work when far away.



What do you mean by lathe reference bar?



Tris said:


> If the bed is true and you turn the ring that sits on the bed bars 180 degrees and clamp the headstock back on it do you then get the axis pointing down (ignore the alignment stops for the moment)?



It only fit's one way. [Edit] actually that won't be problem, so I can try that!



Tris said:


> I think you are chasing an accumulation of small errors here



Quite possibly


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## MusicMan (9 Feb 2021)

transatlantic, a lathe reference bar is, for example








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Find many great new & used options and get the best deals for Lathe Alignment Test Bar Shank Size 1MT, 2MT, 3MT, 4MT, 5MT, 6MT at the best online prices at eBay! Free delivery for many products.



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You have to get the correct Morse taper (probably MT1 or MT2) that fits directly in your headstock (clean it first). Then you know it is pointing directly along the spindle axis and you can align it to the bed.

If you don't have a Morse taper in your headstock, there isn't a really accurate way of doing it, I'm afraid.


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## transatlantic (9 Feb 2021)

MusicMan said:


> transatlantic, a lathe reference bar is, for example
> 
> 
> 
> ...



hmm, I was picturing something much longer. The 2MT says 280mm overall length, so thats only around ~220mm sticking out. Is that really enough to reference against?

Also - is the hole in the end to check it aligns with the tail stock?

Edit : Ah - so these are designed for machinist metal lathes, which is why I assume they're quite short.


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## bussy (9 Feb 2021)

transatlantic said:


> The problem is with turned boxes. When I have hollowed out both the lid and the base (both ends still have their dovetail and initial centering dimple), I then fit the lid to the base, and mount the base in the chuck (using the dovetail), and then bring up the tail stock for support. At which point, even though the piece runs perfectly true, the tail stock does not match up to the centering dimple. If I force it, the lid is forced to not be on straight.



If you have removed the base from the chuck to do the lid, then replaced the base in the chuck, in my experience the base is never going to sit in the exact same position as it was when first turned, i think this could be your problem.
Try fitting the base without tightening the chuck fully, bring up the tail stock then tighten the chuck, if I have to remove a piece from the chuck I always put a mark on the piece and on the chuck so I more or less have the original position of the work piece.
Hope this helps
Marty


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## transatlantic (10 Feb 2021)

bussy said:


> If you have removed the base from the chuck to do the lid, then replaced the base in the chuck, in my experience the base is never going to sit in the exact same position as it was when first turned, i think this could be your problem.
> Try fitting the base without tightening the chuck fully, bring up the tail stock then tighten the chuck, if I have to remove a piece from the chuck I always put a mark on the piece and on the chuck so I more or less have the original position of the work piece.
> Hope this helps
> Marty



I really don't think this is a setup issue. The reason this has cropped up is because I kept seeing the same issue with different boxes, and as I have said a few times now, I can reproduce the same issue with other accessories in the headstock.

- I can put the base back on the chuck. Runs very true (no bumping when you lay a tool on it)
- I can then put the lid on the base. Runs very true (there is no visible distoration of the 'between centers point' on the end of the lid as it rotates)

Yet when I bring up the tail stock, that same center point on the lid is 2.5mm too high. And keep in mind now, that it's running very true, so it's always 2.5mm too high no matter where it is in the rotation. To get it to align I have to undo the chuck and skew the base such that it is not seating correctly, but then the base obviously doesn't run true.


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## Gavlar (10 Feb 2021)

I have exactly the same problem with my Record DML24 lathe. This has a twin tube bed and I had convinced myself that the tube(s) were bent or that they were sitting somehow other than flat. I'd acquired it 2nd hand and partly assembled. I noticed the issue when turning a spindle between centres and then putting in the chuck to drill out the end, e.g. for a candlestick. It ran true, but not centred. On finding a manual online, I discovered that the various castings that hold it all together are handed and need to be assembled the right way round, although that's not obvious when you first look at them. Mine was partly put together wrong. I stripped it down and put it back together, thinking I'd found the problem. Nope, still there. So the lathe is in a box awaiting a decision on its future. Having read this thread, I'll look again at the headstock alignment.


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## MusicMan (10 Feb 2021)

transatlantic said:


> hmm, I was picturing something much longer. The 2MT says 280mm overall length, so thats only around ~220mm sticking out. Is that really enough to reference against?
> 
> Also - is the hole in the end to check it aligns with the tail stock?
> 
> Edit : Ah - so these are designed for machinist metal lathes, which is why I assume they're quite short.


Yes their main use is on metal meths but they are quite long enough for fairly long ones. But it is assumed that you check heights (parallelism) with a dial gauge or test indicator with a sensitivity of 0.001 - 0.01mm. Then you are good to 0.004 - 0.04 mm even at a metre out, which is far less than the problem you are seeing.

If they were much longer, the sag under gravity would become significant.

If you don't have one of these, a good compromise is an internal caliper that is screw adjusted (the sort of thing you will use to measure the inside diameter of a box lid). By carefully checking the distance from bed to alignment bar along its length, you should easily achieve 0.1 mm check on whether this distance is varying. You don't need to know the distance, just that it is constant.

Once you have set the parallelism to the bed, yes you can use the hole in the end to check the tailstock. It is probably more accurate to check the tailstock against a short turned centre close to the headstock. If your bed is humped or hollowed, you will see this with the calipers.


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## [email protected] (10 Feb 2021)

I have a similar problem with my rotating head lathe, however I've not been able to work out what exactly is causing the mis-alignment and have resorted to shims on the tail stock. Obviously whenever you rotate the head you will need to re-align when it goes back to normal. The main issue is that you are probably never going to find out where the error is without some sophisticated (expensive) measuring equipment and probably a lathe specific jig; even if you can there's probably not much you can do about it. I came to this conclusion and whenever I need the accuracy I shim. The problem with shims are that it may only cure the problem at one position i.e. if you are drilling a long hole then it may be centred where you enter the piece but as you drill further it will try to follow the tail stock alignment which may be pointing up or down and you can hear/see this as the drill begins to bind and vibrate the deeper you go. Here I tend to drill very slowly and accept the hole will be slightly bigger at one end than I want. I also use longer pieces of wood fashioned to a point (each time it's mounted) so that I can shim the tail stock to centre at the point I need it to be i.e. at the end of the piece, which still may be pointing up or down. This process works for me and hope that helps. if anyone has a better and more permanent solution I also would be very grateful.


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## IanB (12 Feb 2021)

Sorry I can't contribute any suggestions, but I've recently noticed that when I turn the inside of a bowl, it is not perfectly aligned and I get a rim which varies in thickness by about 1 or 2mm over the circumference - so I'm grateful for some of the suggestions above, which I will look into to find what the problem is.


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## Phil Pascoe (12 Feb 2021)

Bowl turning of course has nothing to do with the bed or the tailstock. I've found the only way to perfection on the rim of a bowl is to turn the inside and outside at the same time (on a single mounting). Turn and finish the base and the side up to an inch or so of the rim then reverse it, finishing inside and outside as thin as you choose. Others may do differently, but it works for me.
If you finish the whole of the outside and leave the bowl even overnight before working the inside you may find it has distorted enough to give that deviation or even more.


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## Robbo3 (13 Feb 2021)

I suspect that the lathe bed has some twist in it. It may be that the lathe wasn't leveled when first installed & not noticed until now or perhaps the lathe has moved from its original spot. Even if this is not the case it won't do any harm to check it out.


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## Dave Moore (13 Feb 2021)

You can buy a double ended taper from Axminster to align the two ends before you nip up the headstock. Not sure if this would solve it unless it is definitely the headstock out of alignment.


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## Phil Pascoe (13 Feb 2021)

Dave Moore said:


> You can buy a double ended taper from Axminster to align the two ends before you nip up the headstock. Not sure if this would solve it unless it is definitely the headstock out of alignment.











Headstock/tailstock alignment


I have the Fox lathe (pictured below) that has a rotating headstock, and have noticed an issue. If I move the tailstock close to the headstock to check alignment of centers (a cone shaped live center at each end), all looks good. But if I turn an 8"piece between centers, turn a dovetail on one...




www.ukworkshop.co.uk


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## transatlantic (13 Feb 2021)

Dave Moore said:


> You can buy a double ended taper from Axminster to align the two ends before you nip up the headstock. Not sure if this would solve it unless it is definitely the headstock out of alignment.



It doesn't really help as the amount of error we're talking about when the tailstock is right next to the headstock (which would be the case when using that tool) is barely even noticeable, and alignment would be forced when you attempted to clamp things down. Possibly damaging the tool, but also resulting in the tailstock now being stuck. That tool is for the case where the vertical alignment is fine, but you're just rotating the headstock into place.


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## jimmy_s (13 Feb 2021)

You could possibly use a laser collimator, you would be able to pick up one off ebay for using to allign the mirrors in a telescope I'd think for about £20. Problem is that it would have a parallel shank to suit a telescope lens rather than a morse taper. It might be enough to let you know whats going on however.

Just a thought


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## Sideways (13 Feb 2021)

How old is this ?
If it's youngish - and this may not be limited to the warranty period - take it back.
If that isn't viable and you are going to need to fix it, then you need to figure out what is happening.
You need to establish
Is the spindle off and drawing a cone ?
Is the spindle simply tilted up or down ?
If the head rotates, does the spindle stay parallel (or at a constant angle) to the bed ?
Likewise for the tailstock - is is parallel / up/down/left/right relative to the bed ?
And is it at the same centre height as the spindle ?

The double taper test bar from Axminster or elsewhere is a good start. At the least, it helps you turn the headstock into line with the tailstock (specifically at close distance - if something's off, then they will misalign as you pull the tailstock back) but it gives you something to measure the direction of the bore with
You also need a measuring gear upto the job. An engineers dial gauge and a magnetic base / arm are where I'd begin. Any model engineering friends or acquaintances you could ask to help out ?
Ultimately, use beer can shims to get it lined up and to show you how big an error is and where, Then carefully remove metal from the opposing points to realign permanently. Not an especially easy job but you may get close enough with a few shims that you can live with that.


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## Inspector (13 Feb 2021)

If it were mine I would measure the ring the headstock spins on to make sure the surfaces were parallel, thicknesses at several points with a micrometer. Then clamp he headstock with ring in it to as flat a surface as you can find, ideally a granite surface plate or table but a granite counter top, thick plate glass, cast aluminium tooling plate, largish milling machine table etc. Put the test bar linked earlier in the morse taper and check that it is parallel to the surface you clamped to. Rotate the ring 90º and repeat the measurement. In a pinch you could use a straight edge and measure to it. That will tell you if the bore the ring sits in is perpendicular to the bore of the spindle. If it is then you need to establish if the bed of the lathe is machined flat, ideally with a surface plate but a straight edge will work in a pinch. Sit the bed machined surface down on the surface plate and use feeler gauges to measure the gaps. Or use the same method with the straight edge. Ideally the straight edge would be the calibrated steel or cast ones made for the purpose but a good quality level like a Stabila would do. The biggest stumbling block for what I have described is going to be finding a flat surface to work off of. 

With all the tools available with my last job I would have put it on a CMM (Coordinate Measuring Machine) and measured the heck out of it but with home CNC milling machines becoming more popular it could be probed on one of them. So if you do have a buddy with one you could enlist their help.

Pete


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## transatlantic (13 Feb 2021)

Inspector said:


> If it were mine I would measure the ring the headstock spins on to make sure the surfaces were parallel, thicknesses at several points with a micrometer. Then clamp he headstock with ring in it to as flat a surface as you can find, ideally a granite surface plate or table but a granite counter top, thick plate glass, cast aluminium tooling plate, largish milling machine table etc. Put the test bar linked earlier in the morse taper and check that it is parallel to the surface you clamped to. Rotate the ring 90º and repeat the measurement. In a pinch you could use a straight edge and measure to it. That will tell you if the bore the ring sits in is perpendicular to the bore of the spindle. If it is then you need to establish if the bed of the lathe is machined flat, ideally with a surface plate but a straight edge will work in a pinch. Sit the bed machined surface down on the surface plate and use feeler gauges to measure the gaps. Or use the same method with the straight edge. Ideally the straight edge would be the calibrated steel or cast ones made for the purpose but a good quality level like a Stabila would do. The biggest stumbling block for what I have described is going to be finding a flat surface to work off of.
> 
> With all the tools available with my last job I would have put it on a CMM (Coordinate Measuring Machine) and measured the heck out of it but with home CNC milling machines becoming more popular it could be probed on one of them. So if you do have a buddy with one you could enlist their help.
> 
> Pete



...I think sometimes people forget that some of us are just woodturners in a little shed out back


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## transatlantic (13 Feb 2021)

Sideways said:


> Ultimately, use beer can shims to get it lined up and to show you how big an error is and where, Then carefully remove metal from the opposing points to realign permanently. Not an especially easy job but you may get close enough with a few shims that you can live with that.



It's about 20 years old.

My plan is to use the test bar mentioned by musicman.

Either this or this (thoughts?). The ones from ebay seem to all come from India and will take a month or so.

I'll put it in the headstock, and then add some shims on the machined ring (under the headstock, see previous pictures) until the point in the tail stock aligns with the hole in the end of the test bar. Once I get it right, I'll then slide the configuration up and down the lathe to make sure it's correct in different places on the bed. Although to be honest, I never move the head stock, just rotate it. So as long as the alignment is ok for the first ~500mm. I'll be happy

... until I need to do something longer that is. 

It's going to be a royal pain in the buttocks no doubt.


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## Inspector (13 Feb 2021)

transatlantic said:


> ...I think sometimes people forget that some of us are just woodturners in a little shed out back



Oh! My apologies for wasting your time. I'll refrain from helping.

Pete


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## Fergie 307 (13 Feb 2021)

The procedure is exactly the same as for a metal working lathe. Mount a test bar in the headstock centre. Now use a dti mounted on your rest so it bears directly down on top of the test bar. Now take a measurement at the far end of the bar, and then slide the toolpost along the bed so the dti runs along the top of the bar until it is just in front of the nose of the spindle. The difference between the two readings will tell you if the spindle is not parallel to the bed. You can check if the bed itself is bowed using a large framing square or a long straight edge, a steel rule will do provided it's long enough. An error of the size we are talking about here will show up very easily.


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## Phil Pascoe (13 Feb 2021)

Inspector said:


> Oh! My apologies for wasting your time. I'll refrain from helping.
> 
> Pete


I thought the comment was a fair observation and not meant to be derogatory in any way.


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## Fergie 307 (13 Feb 2021)

If you know what taper test bar you need why not ask on the metalworking forum. There might be someone near you who would lend you one, and maybe a dti if you haven't got one. Anyone who is familiar with setting up a metal working lathe will be used to measuring this sort of thing to within a few ten thousandths of an inch. Don't know what level of accuracy you need on a wood lathe, I would have thought maybe a few thousandths would be acceptable. That should be quite easy to achieve. Very important not to assume anything until you have some accurate measurements, otherwise you risk adjusting things that weren't actually out in the first place.


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## MarkDennehy (14 Feb 2021)

Or just stick a laser on an MT2 taper in the tailstock and align visually from either end of the bed:










But I'd have thought the double-ended MT2 alignment tool would have been sufficient for most of us. TIL!


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## billgiles (11 Dec 2021)

I am a bit late to the party but check under both the head and tail stocks for a build up of wood dust and oil which affected my lathe alignment.


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## Bod (11 Dec 2021)

1st things first, clean all the crud from all machined surfaces, back to clean metal.
Take a flat oil stone, and rub gently over all the machined surfaces, looking for high spots, usually caused by dinks and bumps during assembly, the idea is to remove the moved metal, which will show up as shiny flecks.
Reassemble and check all alignments.

Bod


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## okeydokey (11 Dec 2021)

For my money I comment
1. make sure the lathe bed is not under tension/out of fully square perhaps caused by one or more legs being bolted harder to the floor than the others, and also ensure the bed has been set up horizontal.
2. Shim the headstock (flattened beer tins work well) and using one of the MT2 Lathe adjustment tools (taper fits in both headstock and tail) you will be able to get the shim thickness and all aligning properly
3. With the known amount of shim thickness you can remove/replace as you wish.
4. When not working between centres the shimming or not is irrelevant.


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## quilldown (11 Apr 2022)

#55, Hi Mark, is that a constant current source in that box for the laser?, i skimmed the the last 3 pages, may have missed the text..


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## billgiles (11 Apr 2022)

If it were metal it would be an issue but wood is flexible so that as the jaws of the chuck close the wood crushes differentially and moves the piece. Put the tenon in the chuck (the shoulders should be up against the lips of the jaws and not bottom out on the chuck). Bring up your tail stock to align with your dimple. Wind the live centre in to push the piece firmly into the chuck. Do up the chuck using each key hole in turn increasing pressure until they all tight. Release the tail stock if you must but don’t be disappointed if there it is still slightly misaligned. It is wood after all not bits for a jet engine.


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