# PCB Milling

# Sainsmart 20k RPM Spindle

## Spindle start code

```
M03 S5000.0
G4 P.25 
M03 S10000.0
G4 P.25 
M03 S15000.0
G4 P.25 
M03 S20000.0
```

# PCB Milling In FlatCAM

If cutting the back (underside) of a board, as would be the case for most single sides PCB's, the gerber MUST be flipped in FlatCAM.