The current version of TurboCNC (V3.24 as of 23/NOV/2003) does not support multi-pass threading. On a weak machine like the FrankenSieg, you can't cut the larger threads in one pass.
I wrote this Excel VBA application to generate the tool paths of the standard metric coarse and fine threads. I didn't bother with the weird metric (M7 M9 etc) BSF, Whitworth, BA, UNF UNC, because I don't use them. If you need them, you will find it easy enough to modify this spreadsheet.
I have it set up to do 29.5° infeeds, and start with a rapid to 1mm larger than diameter and 3 threads from the end of the stock, so be sure you have enough clearance to your live center for supported work.
I cut and paste the tool path into notepad and save it as text.
**Warning**, if you have your computor set up for european numbering like me (Decimal comma), the values in the G code will have commas. Do a search and replace to replace all the commas for dots in notepad.
Disclaimer - I accept no responsiblity for your use of this. If you use it it is at your risk. Don't bother sueing me, cause I'm not in the states and don't have any money anyway.
Update:V1.3 is the latest download.