# Starting position and drilling depth

Using stop rings, you can define the following parameters:

- Starting position of the drill bit

- Drilling depth

Pos | Part | Function
--- | --- | ---
1 | Starting position ring (not required) | Defines the starting position for drilling. This allows for quick positioning of the drill bit at the pre-defined safe distance to the surface. The starting position can be adjusted.
2 | Starting position | Controls the starting position for drilling. Once the starting position ring reaches the disc spring at home position, the motor switches off. NOTE: If the starting position ring is not used, the motor switches off when the lowest part of the spindle reaches the disc spring at home position.
3 | Depth ring | Defines the drilling depth.
4 | Depth position | Controls the drilling depth. Once the depth ring reaches the stop surface, the spindle retracts into the starting position. The motor automatically switches off after retract.

Calculate the drilling depth

You can calculate the distance between the depth ring and the drill head (dimension L in the figure) for the desired stroke D according to the following formula:

L (mm) =D (mm) + 24.95 mm

L (in) = D (in) + 0.98 in