I have Mach3 and Meshcam. I have bought dxf files off eBay and imported, I seem to have no problems with Meshcam, BUT, when I try cutting I end up with a profile of about 2" square. The dxf files are around 200,000 in I want to cut on a 10" square. Ends up in one corner. I Ave read about everything I can find on scaling and am totally confused.
I would greatly appreciate any help.

What size is your stock when you create the g-code in MeshCAM?

Is your machine setup in the same units that you're using in MeshCAM?

X10 Y10 stock thickness 3/8" everything is in inch,
Dxf file imported values 220,456, 195,434, 0,000
Set scaling to 10X10X0.375
Result is a 2X2 that is unrecognizable

Hope that answers question

You may need to calibrate your axis motors.
Read Mach3 doco for that.

Cheers
Roger