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Checking Tail Stock Alignment

I've always checked tail stock alignment by mounting a bar, turning two areas (one near the chuck and one near the tail stock) and comparing them,

I was aware of the method using a 'square cylinder' but, understanding these to be very costly, never obtained one.

While listening on the (amateur) radio this evening I heard another method which sounds quicker than the turning method. I should have 'called into the QSO (contact) but didn't and I'm now curious.

As I heard it, a bit of bar is mounted in the chuck. The bar has a bracket to hold a dial gauge (a 'clock' in conversation) so the tip can rest on either the quill or centre in the quill.

The dial gauge is 'zeroed' at a 12 o'clock point on, say, the centre. The chuck is rotated by hand through 180 and the run out calculated. Repeat at 3 o'clock and 9 o'clock. Adjust the tail stock and repeat.

I'm pretty sure my quill has a groove at 6 o'clock so I'd have to use a centre. I'm not sure if all quills have grooves.

I'm looked on the 'net and sure enough it is there, including on YouTube. However, that doesn't always mean it is proven.

This seems to be a beautifully simple technique. So much so, I'm wondering if I've missed something.

Reply to
Brian Reay
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Well that's the way I've done it for years. It not only shows up lateral miss-alignment, but also vertical caused by shoe wear on the tailstock. Also worth running the gauge along the top of something parallel mounted in the tailstock to test for tailstock tilt. For this you need to carefully slide the tailstock under the gauge having cleaned and lightly oiled its ways.

AWEM

Reply to
Andrew Mawson

On 30/08/13 08:18, Andrew Mawson wro

Thank you Andrew.

I'd been shown the 'turning' method at school and used it when I get a lathe many years later. The "square cylinder" method was one someone told me about but he had acquired the cylinder for a bargain price, along with some other precision gauges.

I'm debating changing my current lathe, a 'badged Southbend' for something a bit smaller. My dexterity isn't all it could be and I'd feel more comfortable with something less powerful.

Reply to
Brian Reay

You can make a functional equivalent to the cylinder square by turning down the middle of some center-drilled stock, leaving raised collars at the ends, then turning both collars to the same size by running it between centers and finishing both at the tailstock end, without changing the infeed. Chuck-end wobble or tailstock misalignment will cause very little error, and you can iteratively adjust it out and take another fine cut to true the collars.

Instead of wasting stock this could be made from allthread with a pair of nuts holding a thick washer at each end for the collars.

The difference between the methods is the loading on the tailstock spindle. I have my 1965-vintage lathe's tailstock set to turn straight when firmly pressed against the workpiece, but a fine drill making a carburetor jet is visibly off center. Trade-school students had abused the tailstock spindle as an anvil horn and the replacement isn't a perfect fit. jsw

Reply to
Jim Wilkins

"Indeed, hardly new at all."

Reply to
gareth

Thank you Jim. Another interesting technique.

I'm sure my lathe is pre-1965, it is one of the many Southbend variants built under some type of licence. I suspect in the 1950s or earlier.

Reply to
Brian Reay

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