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ToolChange Modifier

Insert your own G-code around every tool change in a program, without editing the file by hand or changing your post processor.

The tool runs entirely in your browser — the file is read locally and never uploaded anywhere.

The usual reason to use it

AutoDustBoot. If you retract and expand the boot with M9/M8, the boot has to be out of the way before the spindle goes to the tool change position, and back down after the machine has moved to the first cut. Dropping M9 before the change and M8 after the first rapid puts those commands exactly where a collision is least likely.

G-code file
Commands to insert
Separate multiple commands with commas — M9, G4 P0.5. Inserted immediately before any line containing M6 or M98.
Inserted after the first G0 that carries both an X and a Y following the tool change — the move to the first cut.
Tool changes: —Inserted before: —Inserted after: —Removed: —
ToolChange Modifier v1.0.003

What it changes

The tool walks the program line by line and makes two kinds of insertion:

Where Rule
Before tool change Immediately above any line containing M6 or M98.
After tool change After the first G0/G00 following that tool change that carries both an X and a Y — the rapid to the first cut.

Everything else is copied through untouched, and the result is written to a new file with _modified added to the name — your original is never overwritten. A ; Modified by ToolChange Modifier comment is added as the first line so you can tell a processed file apart at a glance.

Remove these commands where the file already has them deletes existing copies of the commands you entered, so a program that already contains stray M8/M9 lines ends up with them only where this tool puts them. M08 and M8 count as the same command.

Typical AutoDustBoot setup

Field Value
Before tool change M9
After tool change M8, G4 P1

M9 lifts the boot out of the way before the spindle travels to the tool change position; M8 lowers it once the machine is over the first cut, and G4 P1 gives it a second to settle before the spindle plunges.

See AutoDustBoot → for wiring and for the macro side of the setup.

Notes

  • Matching is textual: a line containing M6 anywhere — including T2 M6 — counts as a tool change.
  • If a tool change is never followed by a G0 with both X and Y, the "after" commands are skipped for that change rather than guessed at.
  • Chrome and Edge ask where to save the file. Other browsers drop it in your downloads folder.