View Full Version : Scale problems are driving me nuts!

01-25-2009, 05:17 PM
We are having major scale problems! We believe we have the scale right on TurboCNC because we taped a ruler to the table, and when we jog it at a 16.9 to 1 gear ratio, it moves exactly 1 inch. When it says 1 inch in the status window, it shows 1 inch on the ruler.

But when we try to run a program from Vectric Cut3D, the pass depth on our machine is much greater than shown in the parameters of the program.

We are trying to use a 1/8 inch round ball bur instead of an end or round mill. We are using .0625 as the pass depth, which is 1/2 the diameter of the bur tip. We have tried cut plane settings at the bottom, center, and near the top of the material, but our plunge is still way too deep. We are not sure if we can change anything in the Cut3D program to more nearly match our machine's scale, or if there is something different we can try in TurboCNC.

Any help in figuring this out would be greatly appreciated. Thanks!


01-25-2009, 05:27 PM
Your scale settings in TurboCNC may be close, however they are not correct.


01-25-2009, 05:30 PM

Measure the travel of the axis with a micrometer not a ruler, then re adjust the scale parameters in TurboCNC.


01-25-2009, 05:35 PM

In other words tell software to move one inch, then measure how far the axis travels with a micrometer.

Then re adjust the scale setting in TurboCNC a small amount.

Then run one inch test again, then measure travel.

Repeat proceedure until you are spot on.


01-25-2009, 10:48 PM
Jeff -

Thanks for the helpful suggestions! We went into the Vectric Cut3D program and changed the rapid clearance gap for the Z axis to 1 inch. This is line 3 of their program code. We then ran the first 3 lines of code several times, each time going into the axis configurations and changing the gear ratios slightly, in an effort to "tweak" the movements to coincide with their scale. We got very erratic results. We ran the last 3 times using the same gear ratio, and got 3 different results. So we believe the problem is in TurboCNC.

We have seen mention that TurboCNC will run erratically if in Windows instead of MS-DOS, which might be our problem. Now we are trying to figure out how to ditch Windows and run the program in root DOS!

Thanks, again!

The Blight
01-26-2009, 11:32 AM
Is this TurboCNC 5 or 4.01? If it's 4.01 you can't really run it under windows as windows interupts the data stream to the parallel port. Which version of Windows are you using? If it's an old version, it should have dos as a shutdown option. If it's ME or higher, you will need to make a boot disk. There is actually dos in ME, but it has to be unlocked.

01-26-2009, 01:32 PM
Thanks for your suggestions! We plan to keep working on this, and are looking into the possibility of using a different processor, etc. We are currently trying to run on an old Compaq with Windows 98. We can maneuver in DOS until the actual attempt to call up the TurboCNC, at which point the machine takes us into Windows. Our best option at this point would be a different system. So we are studying which video card, processor, etc. will suit our purposes.

Thanks, again. We have been so grateful for everyone's suggestions and patience with our lack of expertise. We look forward to the day we can be productive instead of frustrated!


01-26-2009, 01:37 PM
I can't understand how starting Turbocnc would take you into Windows? from the DOS prompt, type CD TurboCNC and the tcnc.exe and it should start? Are you in DOS itself, or in a DOS window in Windows??

The Blight
01-26-2009, 05:33 PM
If your in a DOS window, close it, hit start, click shut down, choose restart computer in msdos. You got the same explenation over at the TCNC user group. Good luck!

01-27-2009, 03:37 AM
Gerry, The Blight, and everyone else:

First, thank you all for your helpful suggestions. Being on this forum with such great people is an amazing experience for us!

Regarding the newest suggestions: We do exit Windows and choose the restart in MS-DOS function. We are in DOS at a prompt that says "C:\Windows>". We type "cd\". The next prompt says "C:\>", and we type "cd\turbocnc". The next prompt reads "C:\TURBOCNC>". At that point, if we type in "turbocnc.exe" or "tcnc.exe", which gives us "bad command or file name." If we simply type in "turbocnc", the screen goes black, then goes to "Compaq" followed by "Windows98", and we are back in Windows. No wonder I have little bald spots on my head from pulling out my hair!!

When we go into My Computer in Windows, look at "properties", it tells us the command is C:\turbocnc\TURBOCNC.EXE. But when we are actually in DOS, we keep getting the ">" and think that might be the difference which is the cause of the problem.


Addendum: We shut the computer off completely, then restarted it holding down the Control key. It gave us a menu with 6 choices for startup. We picked the 6th choice, "command prompt safe mode." This got us into Turbocnc without Windows. But we now have no use of our mouse, so can't get into the axis configuration calculations to alter the gear ratios, etc.

So much to learn! Thanks for being patient with us "newbies!"

The Blight
01-27-2009, 04:18 AM
You should not be using the mouse with TurboCNC either way. It causes interferance on the pulse stream (causes missing steps when moving). You can get into the configuration menu by using the keyboard shortcuts. Ctrl C to get into configuration, and either use the arrow keys to get to the desired menu. I don't use the mouse any more with TCNC.

I'm wondering why you can start it in safe mode, and not just with command prompt. Might be some driver interferance when starting TCNC.

01-27-2009, 09:05 AM
You need a DOS mouse driver to use the mouse with TurboCNC. You should be able to get it from there yahoo Group. But, as was mentioned, you don't need a mouse to use TCNC. Everything can be done with the keyboard.

01-27-2009, 10:40 AM

In order to make your system boot up to a real DOS prompt as described, you have to modify your Windows 95 MSDOS.SYS file.
To maximize your free DOS Conventional memory we need to modify your Windows 95 AUTOEXEC.BAT and CONFIG.SYS files. If you just want to maximize your free DOS conventional memory skip the next section.
Here are the procedures step by step:

STEP1: Reboot your Win95/98 system. When you see "Starting Windows 95..." on the screen, hit the F8 key. This will cause the Boot Menu to pop up. Select "Command Prompt Only" and hit Enter. You will soon end up at the C>prompt.
STEP2: Modify your MSDOS.SYS file. It is a read only, hidden, system file. To remove those attributes type: attrib -r -h -s msdos.sys<Enter>

STEP3: Make a backup copy of your MSDOS.SYS file by typing: copy msdos.sys msdos.old <Enter>
STEP4: Edit MSDOS.SYS. Now type: edit msdos.sys<Enter> You will see a section labeled [Options]. Modify the [Options] section and add the lines you do not have as follows (The order does not matter):
BootGUI=0 (This line alone will cause Win95 to boot to DOS prompt only) (Or try these next three or four lines):
BootMenu=1 (This will cause boot menu to always appear on bootup)
BootMenuDelay= 10 (Default is 30 seconds)
BootMenuDefault= Whatever number choice on the Boot Menu you want.
BootMulti= 1 (Add this line if you installed Win 95 over an older DOS (-it will allow you to boot up with the older DOS. It adds an additional boot menu choice)
Logo=0 or 1 (Turns the splash graphic off or on)
Network= 0 or 1 (Again, it depends on your system)
AutoScan=0 OSR2 USERS ONLY-add this command here to stop your machine from running Scandisk on a reboot after a lockup or power outage.

STEP5: Reboot and test it. If it's what you want, put the attributes back on MSDOS.SYS by typing: attrib +r +s +h msdos.sys<Enter>

Note: The above startup configuration also allows you to susequently enter the Windows 95 Graphical User Interface or GUI by simply typing "win"<Enter> at the C> prompt.

Note: If the above does not work, you may have a hidden, system text file named "Winboot.ini" or "Winstart.ini" in your root C> drive directory that is read, on startup, instead of MSDOS.SYS. Rename either and reboot. It should then read MSDOS.SYS and do what we changed it to. So, now we are either booting up to a DOS prompt automatically or by selecting it off the Boot Menu.

01-27-2009, 10:42 AM
You will need to add a mouse driver and edit the config.sys and autoexec.bat to support the mouse in MS-DOS