Centroid Community CNC Support Forum

For a lathe, I'm curious as to why acorn doesn't offer the functionality of using a tool touch off device (or any probe for that matter) for setting up the X-Axis Part Zero (X0) in a similar fashion as automatic tool offset probing which it does support and avoid having to take a skim cut. By giving acorn the diameter of the stylus tip (which is somewhat equivalent to a skim cut measurement) it has all the information needed. The only reason I can think of is that the "Lathe" version of acorn, being a subset of the more popular "Mill" version, simply does not yet offer this possibility. If this is the case does anybody know if a roadmap is known for when this will become available? Tks!

You can set up the tools in X and Z with a probe. On a lathe I do not see a benefit to work with a probe in a toolholder to measure the bar in x and z.

Uwe

What I mean is to set the lathe centerline (X0) using a probe instead of a skim cut/measure. The only way to set the centerline using a probe (that I know of) is to put the probe in the chuck, manually jog x until it trips and manually write the x value. This is more time consuming that making a skim cut/measure which beats one of the purpose in having a probe. So unless I'm missing something Acorn simply needs the Auto touch-off function it already has (to set tool offsets) in the part setup menu to set the lathe centerline.

Plenty of posts about using a probe in a lathe: https://centroidcncforum.com/search.php ... e+%2Blathe

Amazingly, section 5.12 in the lathe manual actually describes using a probe to set tools.

to set tools yes but I'm trying to set the centerline.

Based on what tool you are using touching off is not really accurate. I notice that a positive rake tool will cut under sized after touching off a probe and a negative rake will cut oversized. My only tool that cuts onsize is my parting/grooving tool. If you want accuracy then just take a skim cut with your reference tool.

uchip wrote: ↑Thu Sep 15, 2022 8:14 am to set tools yes but I'm trying to set the centerline.

Centerline depends on the tool. Machine position to the centerline of the spindle changes depending on the length of the tool.
F2 Measure Tool, F5 Auto Tool Touch-off Cycle to Measure X Offset - again covered in the manual.

As Chuck pointed out, a tool setter will get you close but doesn't account for tool, machine, and part deflection under actual cutting conditions. If you want tenths or microns, then skim cut and measure it.

if you have very accurate homing (Zri with Acorn) setting center line is a one time operation.

For best precision on a single part, I program two finish passes with the same depth of cut, measure after the first one, do corrections an run the second pass.

This makes sure all material and machine deflection is taken in to account.

Uwe