Tailstock never stays aligned.

Everytime I use my tailstock on my Harrison L6 lathe it isn't aligned, I have to align it everytime I use it, is this normal?

When using it to drill the end of a bar wpthat has been faced I can visibly see it's not in the centre and the drill bit moves across when it contacts the work.

No matter how long I spend aligning it, the next time I use it it's way out, is this normal?!

No! Specially not on a Harrison. No idea what's wrong though.

.

Are you facing and drilling then moving the work forward in the chuck by any chance.?

Nick

No. Everything gets aligned in the lathe chuck to within 0.05mm TIR.

and the drill bit moves across when it contacts the work.

obviously a tailstock issue

The tailstock should be rock solid

Bad chuck? Morse taper goosed?

Edited By Ady1 on 09/10/2014 01:05:01

Are you spot/ctr drilling first as "drill bit moves across when it contacts the work" suggests not as even if the tailstock was a bit off the drill would align to the spot drilled hole.

If thats not the case then check for muck trapped under the tailstock particularly the V side or wear in the barrel

A well used lathe tailstock should be in alignment when both the tailstock clamp and barrel are locked and any adjustment clamping nut is tightened. Colin

I think the Harrison L6 has a V way so that should act to keep the base inline rather than two flat ways

Hello Chris,

No-one has asked, is this a problem that has developed or has it been a constant problem since purchase?

What I am trying to establish is whether or not it is a 'new' experience, and what has changed to cause it..

Regards Brian

More thoughts,

Is the error completely random, or biased to one side or the other?

It it always present when you are drilling/ Or if you align the two centres to look at each other, move the tailstock away and then back is there a change in position after the movement?

At this stage it is detection work for clues to see what is wrong and why before trying to fix anything.

Regards

Brian

HI Chris
I cold be your drill chuck you are using .
Nobby

Me thinks something basic is being overlooked here.

These old things are too heavy to constantly slip out of alignment without something being obvious. How do you know its moved, do you use an alignment bar every time? with it clamped down on the bed can you physically move it?

Chris

I know nothing about the lathe you have but is there any possibilty that the tailstock is not parallel with the lathe's axis, but at an angle. If it is not, then you could set it on centre at one point, but more or less extension of the barrel, longer or shorter drills would result in an error, Just a thought.

Harold

Is it possible that the bore of the barrel may be damadged ? Maybe the female taper has some scoring and is not letting the male taper seat properly ? The last flatbed lathe i used had a bit of wear and we used to push the tail stock hard against the back way and clamp it as that was where we set the tailstock alignment up on . Maybe the clamp is not sitting right and is walking the tailstock around as you clamp it down ?

If it is a vee bed then as stated earlier maybe there is something stopping the tailstock from seating properly on its vee way . It may be a bit out there but i would run the barrel out say 1/2 of its travel and clamp the lock on then lock the tailstock down then grab the barrel end and give it a good wiggle and see if anything moves .

Ian

Check if your morse drill arbor is bend..

I had same problem with tail stock in the Sieg C6 lathe. Learned out there was drillchuck was not in line, with other word: the MT2 morse drill chuck arbor with tang B6 was bent out of position. Also the tail stock was in line with lathe when i checked with the morse taper dead center meet each other in both head stock and tail stock.

Edited By Jens Eirik Skogstad on 09/10/2014 21:17:54

Just read through this, thanks to all.

I checked the tailstock barrel with a DTI and no movement over 6".

I then put a long length of 8mm stainless in a collet and had 0.1mm of movement on the DTI over every 25.4mm away from the tailstock.

Changed the MT2-MT3 adaptor on the collet and had no movement on DTI over 3".

Problem solved!

Thanks.

Chris,

Do check the taper bore is spotless and check tapers and socket for burrs.

If you want to investigate further, 'blue' the old taper (with a magic marker or sharpie will do) and spin it in the tailstock to see where it contacts and where it doesn't.

If the contact is mostly in the middle, find a way to hold the adaptor reversed in the chuck and supported at the rear, and try turning the middle third of it down by about 1mm with a carbide tool. This 'cheat' is often offered as a way to correct a taper that just wont go right.

Neil

Hello again Chris,

Now that you have found what was wrong, you still have to re-align the tailstock to get it looking in line down the bed again.

If i the sleeve is properly hardened you won't be able to machine it as Neil suggests and if it were mine I would never trust it again even if I was able to salvage it. Bin it and put it down to experience, it has cost you enough time already. already..

Regards Brian