Hi,
you might be more familiar with inch units say, but your machine is constructed with metric ball screws. You could still use inches as your native
units but the conversion will leave them with fractional parts which is confusing.

Do you know what the ballscrews are in your machine? 'No' is not an acceptable answer...find out or measure them until you know...and know for sure
100% otherwise you can kiss any sort of repeatable accuracy from your machine good bye. They will naturally fall into either inch or metric.
Common inch specs are 0.2 pitch or 0.25 pitch. If you measured them with metric calipers the numbers would be 5.08mm or 6.35mm per turn.
A common metric spec is 5mm pitch (ie per turn). You can see that you'll will need to measure accurately to establish whether your screw is
imperial or metric (5.08mm verses 5.00mm). Once you have established what the screws are doing the calculation to find the actual 'Steps Per'
is not too bad.

Craig

OK...I Reformatted Drive, Re-installed XP, Mach, Lazy and  Drum roll please.......IT WORKS ! ! ! !

Thank you all for your help ! ! ! !....

Well Spoke too soon...Back to doing the same Crap....Had Settings at 400, 2000, 300.....Was working.....Today.....
SSDD.......12" = 0.5 " of Movement....I am using Inches.... I am at a total loss

Hi,
did you get around to accurately measuring your ballscrews? If this is a Chinese machine, you mentioned 3040 in a previous post, then
the ballscrews are almost certainly metric. If that's the case the native units of your setup should be metric also.

Native units are about setting up the machine, they have no relevance to what YOU consider normal, they are what the MACHINE considers normal.

Craig

Yes. I re-set as Metric.....Standard......Same thing.....I go with the suggested inputs.....400-2000-300 x and y  and 400-800-100 on the z.... outputs on ports & pins x 16 & 17......y 4&5.....Z 6 & 7...

Hi,
I suspect that your machine is interpreting Gcode in different units at different times.

If you have a Gcode job which is drafted in inches code G20. If the job is drafted in mm code G21.

Clearly you are most comfortable with inch units. I would therefore set your machine up so when you fire Mach up its in inch mode.
Note that's not the same as native units, you'll set those once and never have to touch them again and you will not see or hear of them
either.

On the Config/General Config page, near the middle and top is a box called 'Initialisation String', add G20 to it. Now when Mach fires up it will
be in inch mode.

Craig

Hi,
please confirm Config/Select Native units. Are they metric or inch?

Craig

Hi,
what does

400-2000-300 x

mean?

Craig

400-2000-300 x is the Motor Speeds....I set Native on re-install to Metric....

Hi,
well that all sounds OK.

Try this on the MDI page:
G21 <enter>
G0 X100 <enter>
G0 X0 <enter>

The X axis should move 100mm (nearly 4 inch) and then back again.

Now try:
G20 <enter>
G0 X4 <enter>
G0 X0 <enter>

The X axis should move 4 inches and then back again.

What happens?

Craig