I was setting up cutters on the mill and got hit with this bug TWICE in two days.
CPU: fairly new Dell Vostro box, good keyboard, SW load stripped down.
Mach - latest version, running into Smooth Stepper, fairly recent driver (2.08.02)

Load cutter, bring to near registration point
PageUp to bring tip to registration point (slip 0.25 mm feeler guage between cutter and face)
Nearly there, so tap CTRL/PageUp a couple of times  for the last tiny bit.
OOPS!
I am not touching the keyboard (and the keys are not sticking), but the Z axis is jogging up slowly all by itself! 
Tap the opposite key (PageDown) and it stopped.

Has anyone else met this?

Cheers

Have you read the manual on how to set up the keyboard keys in config?
RICH

Section 3.3 Jogging?
Yes.
If there is something elsewhere which i have missed, please tell me.

However, I had better explain that this has happened only 2 or 3 times in a year of fairly busy use.

Cheers

Seems it's not a repeatable problem which makes it difficult to answer your question.
RICH

Check what your increment step is set to. It may be set to a large value (e.g. 1mm) and your feedrate is set very slow so you're seeing it doing that large increment at a very slow feed.

Dan

Dan, yep probably the culprit, been there and done that but mine usualy puts the end mill into the surface of the piece....
RICH

I know what you mean, Rich

Dan

Not sure if this is your problem - but I have had similar instances.

Windows has a provision that will enable (cause??) a key to repeat when it is tapped while the shift key is being held down. The feature that can cause serious problems when jogging using an arrow key while holding the shift key down.  Tapping another key while the repeat function is active will disable it.  In my case, I generally realize  I have a problem about the time my endmill cuts something wrong. 

There is a way to disable the function, but others have said disabling it can cause other problems.  In windows 7 the repeat rate can be disabled or set for longer or shorter intervals by going into Keyboard properties and changing the settings.  Windows XP also has a provision for changing, but don't remember it it is the same.


Bob @ BobsShop

Yes, I've seen that one more times than I care to think about - happened twice just yesterday.  That is one of the bugs Brian, Greg and I have been flogging for the last month or more, and we're making progress, so I would expect it should be fixed in the near future....

Regards,
Ray L.

Check what your increment step is set to.

I know about that, and it's not that at all. It's a bug.

Cheers