Having some problems threading with a DSPMC and Mach3. Can not seem to get a clean cut and consistent pitch to the point where the thread is a complete mess. The thread looks to start ok in the first few passes but as the program continues the pitch gets lost to the point where the tool looks to be lagging behind. Trying to recut the thread on the same piece of stock starts the thread in a different position radially then the original cut was performed.

Setup is as follows:

- Spindle encoder 1000ppr set to 4000 on config screen

- Cutting rpm is 210

- Thread to cut is 40 x 1.5mm x about 12mm long

- The lathe setup units are in metric but the program file is imperial (G20)

Both G32 and G76 thread cutting has the same issues.

Thread portion of Gcode file below:

N188 T0505

N189 G97 S210 M40

N190 M03

N191 G94 G54 G0 X.8374 Z1.5457 M8

N192 X.7842

N193 G95 G32 Z.8323 F.05906

N194 G0 X.8374

N195 Z1.5439

N196 X.781

N197 G32 Z.8323 F.05906

N198 G0 X.8374

N199 Z1.5422

N200 X.7778

N201 G32 Z.8323 F.05906

N202 G0 X.8374

N203 Z1.5404

N204 X.7746

N205 G32 Z.8323 F.05906

N206 G0 X.8374

N207 Z1.5386

N208 X.7714

N209 G32 Z.8323 F.05906

N210 G0 X.8374

N211 Z1.5369

N212 X.7682

N213 G32 Z.8323 F.05906

N214 G0 X.8374

N215 Z1.5351

N216 X.765

N217 G32 Z.8323 F.05906

N218 G0 X.8374

N219 Z1.5333

N220 X.7618

N221 G32 Z.8323 F.05906

N222 G0 X.8374

N223 Z1.5315

N224 X.7586

N225 G32 Z.8323 F.05906

N226 G0 X.8374

N227 Z1.5298

N228 X.7554

N229 G32 Z.8323 F.05906

N230 G0 X.8374

N231 Z1.5298

N232 X.7554

N233 G32 Z.8323 F.05906

N234 G0 X.8374

N235 Z1.5298

N236 X.7554

N237 G32 Z.8323 F.05906

N238 G0 X.8374

N239 Z1.5298

N240 X.7554

N241 G32 Z.8323 F.05906

N242 G0 X.8374

N243 Z1.5298

N244 X.7554

N245 G32 Z.8323 F.05906

N246 G0 X.8374

N247 Z1.5457

N248 M9

N249 G30 U-.1 W0. M05

N250 M30

Tried the following versions of Mach3, DSPMC plupin, SyncRay file, and FPGA files and all gave the similar results.

- Tried plugin 4.0.9.0 with SyncRaySG-8.11 and fpga DSPMC-E104 also tried plugin 4.2.0.0 with SyncRaySG-9.05 and DSPMC_E901_FPGA, same results

- Tried different versions of Mach3 (v66, v62, and v57) all same results

Tried the special threading logic inside plugin 4.2.0.0 as well with no change in results.

Anyone have an idea how to get threading to work?