tailstock out by 1.8mm

[mike-bolton]

Hi,

The tailstock is 1.8mm above centre when I line it up with the headstock, which makes it impossible to use the tailstock when chucked up.

Any ideas how to fix it.

Thanks

 

[Spindle]

Hi

What type of lathe is it? Is the lathe bolted down to anything?

Try putting some packing under the bed support at the headstock end, (say about 5mm but don't force it), and re-measure the alignment

Regards Mick

 

[CHJ]

Follow on from Spindles comments,

• 1. Is the bed level? not essential but its reference surface should be true and not bent or twisted, the reason for questions above on support and fixing.
  2. Is the headstock spindle parallel to the reference surface of the bed in the horizontal and vertical plain.
  3. Is the tailstock quill likewise parallel to the reference surface of the bed in the horizontal and vertical plain.

The above checks will determine if the tailstock casting is machined incorrectly, either too high or perhaps pointing upwards towards the working end.

If it is truly out in height then dependant upon method of manufacture you may have the option of removing material from the base of the tailstock or packing up headstock/bed interface.

 

[KimG]

Really do rule out any deficiencies in the bed before removing any material though, I made the error of removing a few thou on my tailstock only to find that the bed was slightly twisted (who would have thought a huge cast iron bed could twist?) not I have to recheck centre each time, silly of me.

 

[CHJ]

Really do rule out any deficiencies in the bed before removing any material though, I made the error of removing a few thou on my tailstock only to find that the bed was slightly twisted (who would have thought a huge cast iron bed could twist?) not I have to recheck centre each time, silly of me.

could you put back the erroneously removed metal with a filled epoxy or adhesive shim material.

 

[bugbear]

Hmm. There are lots of techniques for checking accuracy on a metal work lathe. I know of rather fewer for a WW lathe.

Are any of the concepts here helpful to you?

http://www.youtube.com/playlist?list=PL ... xxB8ztUEST

BugBear

 

[WoodMangler]

May seem obvious but... are you sure it's the right tailstock for that lathe ?

 

[chipmunk]

Mike,
As Spindle says it may be easier to help if we knew what sort of lathe it is.

Jon

 

[KimG]

Really do rule out any deficiencies in the bed before removing any material though, I made the error of removing a few thou on my tailstock only to find that the bed was slightly twisted (who would have thought a huge cast iron bed could twist?) not I have to recheck centre each time, silly of me.

could you put back the erroneously removed metal with a filled epoxy or adhesive shim material.

I have considered that Chas, but for now at least I don't find it a real drawback as the movement at the tip of the revolving centre is only about 3mm at a mid range extension, so it doesn't have that much of an effect. Plus I think trying to effect a repair would likely be more trouble than living with the error!

 

[CHJ]

... Plus I think trying to effect a repair would likely be more trouble than living with the error!

I know what you mean, my tube bed is quite long and the bench it is mounted on is very substantial and heavy but the bench moves with the climate and the tubes move with sunlight exposure enough over the 2+mtr length to render finite tailstock adjustment a short term exercise. Just have to check things out when precision hole boring required on chuck mounted items.

One of these days I'll acquire an old metal lathe bed and convert things to a pattern makers setup.

 

[mike-bolton]

Hi,

Thanks for the replies.

The lathe is a rebranded Clark cwl1000 from what I can tell, Its nothing special I know but because I'm new to turning it was just something cheap to get me started to see if I liked it or not.

It is bolted down to a wooden table, from what I can tell is fairly level so I dont think it is that but I'll get round to double checking that tomorrow.

I started turning a goblet on it today with the chuck which has turned out fairly well concidering I haven't got any support from the tailstock, is it really necessary to use the tailstock or just a precaution?

It would be nice to get the tailstock sorted though, so any help would be very welcomed.

Thanks again.

I

 

[Spindle]

Hi

This lathe is pretty basic and I'm sure it won't be long before you decide to upgrade if you find turning is for you. With that in mind I wouldn't spend too much time worrying about the alignment.

However the first thing you could try is to dis-assemble the tailstock assembly and rotate it 180 degrees, re-assemble and re-measure the alignment - if it's better leave as is, if it's worse return the tailstock to it's original orientation.

The other quick fix would be to bond some shim material to the tailstock end of the tailstock to bed bar mating face.

Neither of the above are going to guarantee that the alignment is good throughout it's range but they should improve the situation as the centres move closer together.

Best just to keep practicing with what you have - centre alignment only really becomes an issue when 'long hole boring' and your lathe does not support this process.

Regards Mick

 

[bugbear]

It is bolted down to a wooden table, from what I can tell is fairly level so I dont think it is that but I'll get round to double checking that tomorrow.

In the world of metal work lathes it is notorious that "just" bolting a lathe down can can distort an initially accurate lathe out of truth.

The great Lawrence Sparey, in "The Amateur's Lathe" dedicates a couple of pages to a rather careful bolting down procedure (essentially involving checking as you go and some shims).

BugBear

 

[CHJ]

Now we know what model lathe you have I'd go along with the advice of Spindle and just ignore it, for between centre turning any alignment defects are totally irrelevant anyway, see a bodges lathe for proof.

If you need tailstock support to prevent an item breaking away from the chuck then just fit a wooden cone with a flat face over the tailstock centre and bring that up as a safety stop, any friction marks from poor alignment can or will be removed later.

If your equipment does not allow you to turn an item the way you are trying to do it, then think around the problem and use another method of mounting or process order.

Nothing says a 'Goblet' for instance has to be turned in one piece.

 

[mike-bolton]

Hi

I've decided to take it back and get a refund and upgrade to a better lathe, something like the axminster hobby or a second hand one if anything pops up.

The only thing now is I'm stuck with my axminster clubman 3/4 x 16tpi chuck and if I decide to get the axminster hobby the thread on those is 1" x 8tpi. So the question is whether to send the chuck back in exchange for the right thread size for the hobby or get an insert to fit into the current chuck.

Anyone used inserts and if so are they any good?

 

[KimG]

I use one on My Jet 1642 with a Sorby Patriot chuck, it works fine and I have turned some hefty pieces on it, it does reduce the distance between centres a little but that has not been an issue so far.

 

[Grahamshed]

I could well be wrong but have been looking at chucks online for the last couple of days and have been left with the feeling that most chucks deal with the different sizes needed by using different inserts ( i.e., they don't make chucks in all the different thread sizes )
I am happy to be corrected though.

 

[CHJ]

I could well be wrong but have been looking at chucks online for the last couple of days and have been left with the feeling that most chucks deal with the different sizes needed by using different inserts ( i.e., they don't make chucks in all the different thread sizes )
I am happy to be corrected though.

Usually inserts are only the case with smaller threads, larger threads are too big in diameter, near enough the same as the inserts, to use a thread insert. Larger threads are usually cut directly into the chuck body.

The ability to change thread inserts for the smaller thread diameters is dependant upon the chuck design and differs between manufacturers.

Fitting an adaptor between the spindle nose and the chuck as opposed to a different insert can increase the risk of run-out due to the introduction of two more thread interfaces and quality of fit.

On a lathe with less than perfect bearings it can increase chatter risk because they project the chuck further away from the bearing support.

 

[Grahamshed]

I could well be wrong but have been looking at chucks online for the last couple of days and have been left with the feeling that most chucks deal with the different sizes needed by using different inserts ( i.e., they don't make chucks in all the different thread sizes )
I am happy to be corrected though.

Usually inserts are only the case with smaller threads, larger threads are too big in diameter, near enough the same as the inserts, to use a thread insert. Larger threads are usually cut directly into the chuck body.

The ability to change thread inserts for the smaller thread diameters is dependant upon the chuck design and differs between manufacturers.

Fitting an adaptor between the spindle nose and the chuck as opposed to a different insert can increase the risk of run-out due to the introduction of two more thread interfaces and quality of fit.

On a lathe with less than perfect bearings it can increase chatter risk because they project the chuck further away from the bearing support.

As I said. Happy to be corrected

 

[mike-bolton]

I've been looking at the record power dml36sh with a swivel headstock that looks pretty good, and my chuck will fit the thread.

Is this lathe any good? Does anyone own one or used on that could give any advice about it.