Mini lathe spindle lock - videos

Mini lathe spindle lock. By ADES WORKSHOP.

40:29 video:
https://www.youtube.com/watch?v=9gjPRAm0aTE

46:35 video:
https://www.youtube.com/watch?v=fIn__qGZAhA

Hi Ade, I like the idea and the lock you have made, how did find the depth of the mounting bolts, that is not penetrating the cast housing?