Setting the zero point on a CNC lathe

[m_c]

Without having various preset toolholders, there are only two reliable options.
1) take a skim cut and measure.
2) use a probe. However for the cost of an accurate probe, you'll be able to buy lots of toolholders!

Getting a QCTP can't be recommended highly enough. They save lots of time, and once you've got one you'll wonder how you ever managed without one.

[Robin2]

How do you preset the tools in the quick-change toolpost?

I thought all a QCTP did was to install the tool at the correct height? Can't you rotate the toolpost holder to change the angle of the cutting tip?

I presume if you take a skim cut it is essential not to move the tool until after you have measured the effect?

With apologies to everyone who already knows all this ...

...R

[m_c]

How do you preset the tools in the quick-change toolpost?

The same as you would in a normal toolpost

I thought all a QCTP did was to install the tool at the correct height? Can't you rotate the toolpost holder to change the angle of the cutting tip?

Once a tool is setup in a QCTP holder, it's just a case of swapping the holders, and the tool should remain in the same position.

I presume if you take a skim cut it is essential not to move the tool until after you have measured the effect?

Yes.
Using a QCTP, you'd setup each tool in it's own holder, take a skim cut with each tool, and store the offsets for that tool within the software. Then it's just a case of telling the software what tool is installed.
The only issue is on startup, you need to reference the X-axis, which can be done in one of two ways.
Either you setup one tool as a master tool, which all other tools have their offsets stored from, so when you startup/need to recover from loss of position, you take a skim cut with any tool, measure and use the measurement to set the axis position;
The alternative is install a home sensor (highly recommended as it makes starting up or recovering from crashes easy), and then it's just a case of homing the lathe at startup/after loss of position.

With apologies to everyone who already knows all this ...

No need to apologise. Setting up lathe tools initially can be a bit intimidating, but once you've got a couple setup, things start to make sense.