WABECO 8 position lathe tool changer



When thinking about it, it seems that the 8 position WABECO lathe tool changer standard code supplied with the MASSO G3 lathe would also work fine with a similar tool changer that has only 6 positions, or even fewer. As long as the number of forward and reverse lock steps were set correctly it should go to the called tool.

Is this correct?

My current tool changer has these features: 6 position, unidirectional, no home sensor or other sensors, stepper motor driven. I could add a home sensor for tool 1 if required. I don't know if the home sensor required for the WABECO has any function after homing the turret. When I power on my lathe (with its current controller, not MASSO) the tool turret does nothing. It's up to the user to make sure tool 1 is in position (it is set as the default startup tool on a setup screen). If tool 1 is not in the correct position the turret can be indexed via an index button on the screen until it is (without affecting tool offsets etc.), then a program can be run. The XZ offsets for tool 1 are always set to 0.

Any comments would be appreciated.

Thanks in Advance,



Staff member
Hi Mark,

I don't think that the 8 position Wabeco Lathe tool changer would work with a 6 tool version.
While you could Home it to tool 1 and set the steps to move the correct number of steps to get to each tool easily enough the problem would be when you wanted to go from tool 2 to tool 1
Since the tool changer knows it needs to move another 7 positions to get from tool 2 to tool 1 you would end up at tool 3.

Is this a standard Wabeco tool changer or is it a Wabeco style tool changer?
Do you have any documentation on it along with a description of the required logic please?
I had a quick look on line but all I could find was 8 position tool changers by Wabeco.

We would need to look at the tool changer and the required logic to see what was needed to support this type of tool changer.

Regards Peter


Hi Peter,

Thanks for your reply - yep, makes sense. Sorry I haven't been able to reply sooner. My lathe tool changer is a sort of standard-issue Chinese-made turret unit that originally had a fixed-in-place ring with qty 6, 24V Hall effect sensors to detect each tool as the turret rotated and also a separate home limit switch. The motor was originally a 3-phase motor. Modifications were made by the U.S. vendor that replaced the original motor with a stepper motor and made the use of the sensor ring unnecessary (it's not used at all at present). So I think it works just like the Wabeco, except it's 6 stations instead of 8. Photo attached.

The rotation is unidirectional only. There are no sensors at all. The current lathe software has a button to index the turret by one tool every time it is pressed. This is used when at startup the first tool that is called in a program (almost always tool 1, or maybe that's tool 0 for Masso) is not in the cutting position in the turret. Indexing the turret manually does not change the current tool number in the software. The software allows setting the default tool when the software is started. So it's up to the user to make sure that the first tool called in a program is the one currently in cutting position in the turret. That's fine for the home shop (like mine), but not so great for a commercial shop.

It works like this:

1) Tool change line in g-code file is encountered.

2) Stepper motor rotates the turret X number of steps in the CW direction (viewed from front side of changer) to release the turret and allow rotation to the called tool. The number of steps sent is the amount of steps required to index one tool position times the number of required indexes to get to the called tool. There is no pawl pin etc. that needs to be released.

3) Stepper motor rotates the turret Y number of steps in the CCW direction to allow the turret to lock, plus additional steps just to make sure it's locked (stepper motor stalls and misses steps).

It's very simple and works well. The setup screen image is attached. In my setup the unidirectional box is checked, and the 'lock tool changer output' is not used. What's nice is that it's configurable and the number of tools per turret can be any number - might be something you can add. I'm considering upgrading the controller because the motion control board being used is relatively primitive by todays standards. I can add a home switch for the turret or use the existing one if required.



  • tool-changer.JPG
    13.1 KB · Views: 56
  • current-tool-changer-setup-screen.JPG
    75.4 KB · Views: 54