Tailstock alignment.

[brightspark]

Fixed will always stay put better than any live - but I'm sure you've seen the, erm, variable quality of live centres.

yup I bought a jones and shipman one for 8 quid at autojumble

 

[Gareth J]

Or, turn a bit of bar the same diameter as the tailstock tube and butt them together. Then, with a dti, adjust the tailstock so it's aligned along the whole length of the exposed tailstock tube.

This way you've a hope of getting it close to target along its length. You can also make judgements about what compromises you may have to make because of wear.

 

[rikrobson]

I have a spare boxford vsl reducer l00 to mt3 will that fit?

 

[grim_d]

According to lathes.co.uk the internal taper on the vsl spindle is mt5, so too big!

Thank you for the thought however.

Or, turn a bit of bar the same diameter as the tailstock tube and butt them together. Then, with a dti, adjust the tailstock so it's aligned along the whole length of the exposed tailstock tube.

This way you've a hope of getting it close to target along its length. You can also make judgements about what compromises you may have to make because of wear.

That's also a good idea!

 

[graffian]

I align mine with a dial gauge.
I have a length of bar with a slot in it and the gauge clamps in the slot.
Here it is aligning something for boring, setting the tailstock is pretty
much the same.

 

[indy4x]

Hi all,

Unfortunately I am missing the reducing bush for my Harrison spindle (4.5mt to 3mt) so I cannot mount a centre directly into the spindle (or indeed a test bar) and they command £200 on ebay. Similarly I do not have the skill or tooling yet to make one.

Are they selling for that much???

I put one on there a few months ago as I had 3 kicking about, 99p start, no reserve and it made £40-

 

[grim_d]

Are they selling for that much???

I put one on there a few months ago as I had 3 kicking about, 99p start, no reserve and it made £40-

Unlikely. I certainly wouldn't pay that for it.

It was the only one on ebay I could find. I can live with the 4 jaw.

 

[grim_d]

So I've just realised this thread is actually in the wrong section...nevermind!

My dead centre and a few other bits arrived this morning, got the fancy carbide tipped one!

Had a go tonight and the first cut was 0.03mm out over 6 inches, adjusted the tailstock and took another cut, bang on, well as close to bang on as I can measure as my little mitty mic only has a resolution of 0.01mm.

Absolutely delighted, another box checked off. Thank you all for the advice!

 

[Bill Edwards]

What a result!

 

[brightspark]

have u checked the bed for being level and not twisted

 

[brightspark]

Not so much level imo (a lathe will cut exactly the same if it's level, at 45 degrees, bolted to a wall or hung from the ceiling) but twist is important.

Now do another longer bar with the tailstock at the far end of the bed

that's what I was referring to twist in bed I did state that in post the twist can be checked if u have a decent machine level

 

[grim_d]

Only with a moore and wright engineers level on the bed. Not by cutting a test bar as yet. I will get there! I have a little project for the house where I need to make a little bush for a velux window so needed my tailstock aligned.

@pdg that was the longest peice of machinable bar I had lying around. It gets me going for now!

 

[Gareth J]

Run a dti along the barrel of the extended tailstock. It should be as close to parallel to the ways as possible. Otherwise you may only be aligned at a certain point of extension. Any misalignment will be exaggerated by longer grill bits and the like

 

[Pete.]

Here is how you align your talistock centre with the spindle.

Use a micrometer to measure the diameter of the tailstock sleeve. Put a piece of steel/ally in the chuck and turn it to the exact same size as the tailstock (make sure you let it cool right down for the finish pass especially if it's ally). Now bring your tailstock up to touch the end of the sleeve up to the collar you have turned. Mount a dial gauge somewhere on the carriage so it is reading on the side of the collar and move the carriage to sweep it across to the tailstock and adjust the alignment until the gauge reads the same on both. Repeat on the top of the parts to check the height is the same and shim if necessary. If you do need to shim the height, do the sides again.

 

[doubleboost]

The bit you want starts at 9.00
https://www.youtube.com/edit?video_id=VHK3WThDLGs&video_referrer=watch

 

[Gareth J]

Here is how you align your talistock centre with the spindle.

Use a micrometer to measure the diameter of the tailstock sleeve. Put a piece of steel/ally in the chuck and turn it to the exact same size as the tailstock (make sure you let it cool right down for the finish pass especially if it's ally). Now bring your tailstock up to touch the end of the sleeve up to the collar you have turned. Mount a dial gauge somewhere on the carriage so it is reading on the side of the collar and move the carriage to sweep it across to the tailstock and adjust the alignment until the gauge reads the same on both. Repeat on the top of the parts to check the height is the same and shim if necessary. If you do need to shim the height, do the sides again.

This. Also mentioned above

 

[Pete.]

Damn, sorry Johnser, I don't know how I missed that.

 

[Gareth J]

Damn, sorry Johnser, I don't know how I missed that.

No need to apologise. Worth writing again as you put in much more detail anyway. Tbh, I wasn't sure there was an accepted method that's just what I did as I couldn't think of another, better way.

 

[grim_d]

Yeah it does seem a good method, essentially you are creating a test bar. I certainly don't have a piece of bar big enough for it however..

@doubleboost The video doesn't work for me, takes me to an upload page. There is a good chance I've watched it however!

 

[Gareth J]

I certainly don't have a piece of bar big enough for it however...

A bit of sturdy pipe will work. It's not really a test bar, only needs to have enough machined to be measurable and get a good reading with a dti.