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@@ -186,28 +186,30 @@ this flag with caution on other machines.
The G-code produced should work out-of-the-box on ShopBot machines. Other
machines may need some fine-tuning.
+### Preamble
+
The default G-code preamble is
```
-G00 G90 G80 G28 G17 G20 G40 G49
+G00 G20
M03
```
-The `--preamble[-file]` and `--epilogue[-file]` options allow you to specify
-a custom G-code header or footer to override the default. Note that in writing
-a custom preamble/epilogue, you should *not* include line numbers; the program
-will automatically insert them on each line of the supplied preamble/epilogue.
+This tells the machine to use inch units (`G20`) and then starts the
+spindle (`M03`).
-If the default preamble is giving you issues, try the following stripped-down
-version:
+The default G-code epilogue is
```
-G20
-M03
+M05
```
-This will only tell the machine to use inch units (`G20`) and nothing else. It
-should work with virtually any machine.
+This does nothing but stop the spindle.
+
+The `--preamble[-file]` and `--epilogue[-file]` options allow you to specify
+a custom G-code header or footer to override the default. Note that in writing
+a custom preamble/epilogue, you should *not* include line numbers; the program
+will automatically insert them on each line of the supplied preamble/epilogue.
## Metric Units
@@ -215,10 +217,11 @@ Passing the `--metric` flag will replace the default `G20` directive with `G21`
to force metric units. If this is passed, all measurements given will be
interpreted as millimeters. E.g., `--width 100` will be interpreted as a width
of 100mm. (That is to say, the `--metric` flag is comparatively dumb; no
-internal unit scaling takes place.)
+internal unit scaling takes place -- only the preamble is changed.)
Note that the `--metric` flag cannot be used in conjunction with
-`--preamble[-file]`. If a custom preamble is necessary, just include `G21`.
+`--preamble[-file]`. If a custom preamble is necessary with metric
+units, just include `G21` in the custom preamble.
## Pen Plotting