From: Robert Bastow <"teenut"@ hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Live centre with straight shank
Date: Fri, 10 Dec 1999 17:24:49 GMT

People do seem to have an inordinate fear of moving, and consequently,
realigning their lathe tailstock.

Here is a quick and accurate way to do it:

Chuck a stub of (any) metal in whatever chuck or collet happens to be on the
lathe at the time.

Skim the O/d to any diameter you like, face the end and center drill. (while
center drilling you will be able to "Eyeball" the tailstock within a few thou or
closer, to center)

Part off a slice from the end of the bar..about 5/16" long.

Reface the stub left in the chuck.

Using the tailstock center, hold the parted off slice up against the stub in the
chuck.

Adjust tailstock until no discernable step is seen or felt at the interface (The
human eye and finger tip can detect a step of less than a tenth of a thou)

To speed up the process next time..make the stub an "aliquot" dimension..or note
its size carefully.  Keep the slice in your toolbox, and next time you need only
face and turn a stub to the same diameter.

If you have accurate collets..make an accurate stub and slice.

To align centers...make two slices, both accurately centered and hold them face
to face with the centers.

This method will also enable you to measure any vertical displacement very
accurately...

Measure the stub/slice diameter, put them face to face, measure the diameter
across the inter face.  Displacement is HALF the diference between the two
measurements.

When moving the tailstock over or back to center, always use a dial indicator (I
use a BIG 20 millionths clock) mounted on a magnetic stand on the back of the
lathe.  That way you can set or return the tailstock precisely and QUICKLY.

Be not afraid!

8^)

teenut

mulligan@advinc.com wrote:
>
> In article <slrn84vqmp.ttj.beer@sauron.ucs.sfu.ca>,
>   beer@sfu.ca wrote:
> >
> > I saw a tip on using a boring head in the tailstock to turn tapers.
>
> Why not just set over the tailstock?  Does the same thing, and
> does not cost the boring head.  If you do use the boring head
> be sure to clamp the dovetail on it to keep it from moving during
> the cut.
>
> The forces involved at the center are pretty big, be sure the
> head is robust enought to handle them.
>
> Jim