Scootopia rear hub

Hi Guys
I am replacing a Uni rear hub with one of the stronger type Scootopia ones
The threads in the Scootopia hub are onely tapped ( actual threaded part ) to 6mm deep but the Uni one is threaded 10mm deep. this means my lock washer Allen bolt bottoms out in the thread before clamping the washer - 6mm doesn’t sound like a lock for when I need to pull the bulb in the future.
Does anyone know if the 6mm depth is correct for this hub or do a I have an ‘odd’ one ?
I am replacing a Uni rear hub with one of the stronger type Scootopia ones
The threads in the Scootopia hub are onely tapped ( actual threaded part ) to 6mm deep but the Uni one is threaded 10mm deep. this means my lock washer Allen bolt bottoms out in the thread before clamping the washer - 6mm doesn’t sound like a lock for when I need to pull the bulb in the future.
Does anyone know if the 6mm depth is correct for this hub or do a I have an ‘odd’ one ?