Help on correlating G-code to machine movement

[SteveS]

It seems that I am having a newbie mental block or am setting something wrong.

In late 2004, I bought a turn-key CNC router table off Ebay from a person in Wixom who bought it and never used it. The brand was Debece and included a German CAM software package. The machine uses a serial interface, so unless I change out the controller, I am stuck with the German WinPCNC software. The company is of no use, seem it is an reseller from Germany and I haven't found the parent connection.

I have Rasterfratz, Mach2 and BobCad V20 software. Since the CAM side recognizes HPGL, I also have Corel.

My real problem is that after creating G-Code from any of the software packages, the size isn't what I expected in the CAM software. It always is much smaller on the CAM display and after cutting it. To date, I have only attempted 2-D.

The machine working surface is physically 46 by 76 cm or 18 by 30 inches.

In manual mode, if I direct the machine to move 100 units, it goes 47 mm / 5.7 inches.

When I run the machine in manual mode to its X limit it shows 3300, for the Y axis it shows 2100. Again, it is only 760 mm X and 460 mm Y. Those limit numbers are where I stopped so not to crash. Seems like a factor of 4.3 to 4.5 difference.

Nanotec bi-polar steppers with 200 steps per revolution. ST5818M3008A for Y, ST5818L3008A for X and ST4018M1206A for Z.

Thanks in advance for any advice.

Steve.

[Al_The_Man]

I wonder if the original owner had it set up or commisioned correctly, it could be the machine just requires scaling to obtain the correct movement, but you would need to know the parameters involved to do this.
Al.