alinement of tailstock

Hi all, been looking and trying to set my tail stock to be dead centre on my exe 3.5 super, ive managed to get it within a thou to two side to side (towards/away from operator) but its still a little high, at least 0.5mm which i think is 20 thou i think. I have a dial gauge but over the 10" its a little "wobbly"? so ive ran the gauge side to side a number of times to check.

my question is is this high within tolerance? if not how can i adjust it, i think its level/parallel to the bed.

Hi Lioyd,
Can you describe how you are checking the tailstock centre height in case the error could be in the method you are using rather than a real error.

Les.

Hi Lloyd

Put the lathe centres in the headstock spindle and tailstock, bring them together and insert a thin flat strip such as a Stanley knife blade between the points. Bring them in light contact. If the centres are in alignment the strip will remain vertical. If your tailstock really is .5mm out of alignment the strip will deflect. This test can be remarkably sensitive. The centre points must be in good condition, not bruised at all.

Jim

Hi Lloyd
How about putting a dti in chuck . slide talstock forward a lock . set the clock so you can rotate it around the barrel check front to back first for any error .. adjust tailstock then check top and bottom .
Jims is a good method do that first , Also go on to Utube & have a look there.
Nobby

hi all, thanks for the surgestions i think ive basicly done what you've said nobby but dont own a sensitive dti,  im just got a plunger type, so exspected a thou or two difference, i used a magnetic holder for my dial, which was fixed to the chuck then the dial on the revolving centre that i have, checked it first at the back face, then the front face (side to side) then turned it to the top and saw it was out compaired with the sides.

I didnt do the outside of the quill incase the quill wasnt concentric. i done this close to the chuck first, then moved it back to about 10" where i need it for one bit im doing, i cant remember if both near and far were the same amound out?

Edited By Lloyd Bowers on 19/02/2013 11:05:36

Hi Lloyd,
Could it be that the 10" bar supporting the dial guage is flexing with the weight of the dial guage. When the dial gauge was above the quill it would sag causing a high reading. When it was below the quill the sag would cause a low reading.

Les.

yeah i did think of that, but i dont think it would be all that much, and there was a little near the chuck. im going to try a stiffer bigger bar to hold the gauge..

am i right in thinking high isnt as important as side/side?

Put two good pointy centres into the head and tailstock tapers and bring them together by eye

The headstock is the critical bit for workholding

I can't see you getting "true alignment" from a hobby lathe tailstock because it travels up and down the bed so some small errors will always arise

edit

Normally the pointy bits should show the same height and the only adjustment is from side to side

If the height is obviously wrong take it to bits and clean it up and have a good look at it

edit2

Don't forget that the tailstock barrel can be wonky/loose inside the tailstock housing, this is an old hobby lathe we're talking about and some errors you will have to accept and deal with as you do your metalwork

Edited By Ady1 on 19/02/2013 11:31:41

ok, thanks, will do and recheck.

Don't view your tailstock as a high precision part, more as an aid to workholding which needs to be as close as possible to the centre point of the headstock

If you're tailstock isn't well adjusted then it can break small drills because it isn't drilling straight down the centreline

If it drills a nice neat hole down the centreline when you have a workpiece in the chuck then that's all you can really expect of it

gl

Make an arbor which you can place between the centers, as long as possible, solder on the ends a small length of larger diameter. When you turn, without changing the tool setting, the same diameter at headstock and tailstock end, your tailstock is in alignment. Niko

Hi Again
I have a mandrel I ground between centres approx 9" long . that I used to check my 2&1/2" exe lathe before cleaning up Nobby
.

ok i see. thanks. ill try it and see. do you also double check the tool is centred at both ends before or after?

yep the bar worked, kind of? some how end to end was fine or ajustable to be fine. but the middle was slightly thicker? is that flex in the work piece due to the pressure of the tool acting on it?

> is that flex in the work piece due to the pressure of the tool acting on it?

Most likely it is, unless the centre portion of the bed is worn.

Neil

Hi
A traveling steady would help Similar to this
Nobby

The centre/Chuck end of your bed is probbly worn to some extent

The same probbly goes for your main leadscrew

Your crosslide leadscrew is probbly the same, more wear in the middle

You'll pick these things up as you get more experienced with your unit and fix or work your way around them, usually they are too minor to correct "for all time"

What I ended up doing was only doing things accurately when it was essential

Most of the time mega accuracy is unnecessary, your lathe will do a lot of hard work roughing stuff down, milling etc

This knocks things about

For any "final cuts" you get serious about accuracy, nipping up the slides etc

The main thing is that your headstock bearings/spindle are decent, a wonky headstock is bad news

Edited By Ady1 on 19/02/2013 22:11:15

i hope not. dont try to worry me with those possibilites.

does the fixed steady fix to the cross slide?

The fixed steady goes on the lathe bed

The travelling steady goes on the back of the cross slide saddle