Thread: Testing for alignment.

A very simple method is to place a dead centre in the tail stock and the head stock, slide the tail stock to the head stock until the centres meet lock the tail stock
and if the centres are still in alginment the you are ok

China.
I understand that bit, but what about at the end of he bed when head stco and tail piece are apart by about 1/2 metre. Will that still be ok??

Originally Posted by cookie48

China.
I understand that bit, but what about at the end of he bed when head stco and tail piece are apart by about 1/2 metre. Will that still be ok??

The farther apart they are the less it matters that they perfectly align.

One way to check would be to securely put a 50mm square piece of timber in your chuck, with the end roughly centered on the point of the tail center. Scoot the tail center close to the end of the piece and lock the tail stock to the bed, advance the center enough to make a mark in the end of the timber and back it out.

Rotate the chuck and watch the relationship of the hole and point. If the mark in the piece makes a circle in relationship to the point of the tail center, you have 1/2 the circle of misalignment

Assuming a spindle 25mm or larger, for my taste, a circle 10mm or less would be fine in a half meter.

To cut a taper on a metal lathe, one can set the tail center over and drive the spindle with a drive dog and plate. The carriage will move the cutting tool parallel to the bed.

See: http://edu-support.blogspot.com/2013...r-turning.html

I have a few centres (spur drives and cup centres) that are bored all the way through. If you insert them into the head and tailstocks and look through them from the handwheel ends you can site the centre at the other ends of the bed.

Kissing centres tells you part of the story. It's possible for centres to kiss when together but not be true to your lathe bed. eg

The above method gives you and indication whether the Morse tapers are true to the bed.

Centres apart diagram.jpg

As I said it was a "simple method" if you want to go high precision obtain one of these http://pinlaser.com/applications/lathe-spindle/

Thanks but I think I will go for the cheaper version.

You don't have to go to quite that degree (http://pinlaser.com/applications/lathe-spindle/) to align a wood lathe. Ya got a cheap(ish) laser pointer? Last I looked, Officeworks & Dick Smith were selling 'em for <$50.

Put a spur in the tailstock, then wedge the pointer fairly solidly into the headstock spindle's taper. Try to afix it in such a way that the laser targets the centre of the tail-spur, but it doesn't matter if it's slightly off-axis; just so long as you can see the dot somewhere ON the spur.

Slowly rotate the headstock spindle and watch the 'orbit' the dot takes on/around the spur. The centre of the orbit is where a headstock drive-spur would 'kiss' on the tailstock.

It's a rough'n'ready method... but it works well enough for wood lathes and it's cheap!

(I paid almost as much for a double-ended MT that will only align things when the tailstock is brought up to the headstock. It was a waste of coin, IMHO, as a simple kiss test does the same thing! )

Originally Posted by Skew ChiDAMN!!

You don't have to go to quite that degree (http://pinlaser.com/applications/lathe-spindle/) to align a wood lathe. Ya got a cheap(ish) laser pointer? Last I looked, Officeworks & Dick Smith were selling 'em for <$50.

Good idea!!

On this side of thew bond a laser cat toy can be bought for as little as $0.97:

http://www.petsmart.com/family/index...FdJ9Ogod61AAPA

Also laser pointers from office supply stores:

http://www.miniinthebox.com/laser-po...FeYDOgodNR0ALQ

As they are mostly made on your side of the pond, they should be available in AU.