Setting up tools on a lathe

[suntravel]

I hope my spoking English is not too bad

Since some users have problems with setting up the tools on a lathe, I made a video on this subject.



Uwe

[cnckeith]

right on, thanks for sharing your knowledge! , copying this to the videos forum as well

[Muzzer]

I note this video assumes the touchoff probe is mounted in the spindle on the centre line. I believe the "problem" I have with my lathe is due to the fact that my touchoff probe has to be mounted "behind" the spindle axis. That's because my turret can't physically move beyond the axis of the spindle. When I need to touch off a boring bar, the probe needs to be 1-2cm offset beyond the axis of the tool shank. It was in this context that I found the auto touchoff didn't work as described.

I will revisit this at some point soon - but unless there has been focused effort on the part of the Centroid team to investigate and correct the issue that I'm not aware of, I'm not imagining it's been fixed yet.

There must be a concern that this kind of asymmetrical behaviour could impact the behaviour of the spindle mounted probe if it isn't perfectly concentric. I don't understand what the error was caused by, as I couldn't discern a clear pattern of behaviour.

I wonder if you'd be willing to repeat your tests with the probe offset radially 1cm or so and see how it behaves with a boring tool?

[suntravel]

Is your lathe with rear mounted turret ?

Uwe

[cncsnw]

There are, of course, many machines with built-in tool setter arms.

On those machines, the tool setter is not on the spindle centerline.

Therefore, an off-center tool setter is a normal condition that the software should be written to handle.

[suntravel]

Yeah, my first CNC Lathe +30 years ago was a Mazak QT8 with tool setter arm.

I asked, because I am pretty sure auto measure on rear mount configuration has a bug anyway.

I would prefer not to use the reference tool solution on a lathe, but a fix XZ zero for the machine coordinate system in front of the chuck and two parameters for the XZ center of the tool setter, for its XZ size there are already parameters in use now. In this case with two more parameters for the XZ location of the turret tool holder mounting surface, tools could be measured outside the lathe too.
The cream would be a full integrated Y axis

But the reference tool configuration can work with off center tool setter also if the internal calculation is done right.

Uwe

[suntravel]

This is the reference point system I am used to on CNC Lathes with turret.

For DIY conversions of manual lathes, I think the reference tool system like it is now is better.

Uwe

[johannes]

When using the reference tool method, I am confused by how to measure threading tools and chamfer tools.
For normal tools, I can simply measure at the furthest point in X and Z. But which point(s) do I then compare that to for chamfer and threading tools??

[tblough]

It all depends on how you are going to program them. You have to use them in your CAM system the same way you measure them. You can have multiple tool offsets for each tool to accommodate both options on the middle and right tools.

[suntravel]

With an TTO you can only measure the furthest point in X and Z.

So you have to correct the Z offset by hand with the known or measured distance to the tool tip, if your g-code is made for the tool tip.

With threading tools I simply use the furthest point in X and Z to avoid hitting a shoulder on the part.

Uwe