Clock Repair Archive – –
To put a hole in a suspension spring: use a sharp punch with an aluminum block on the bottom of the spring. Strike the suspension spring using the punch and a small hammer. The punch must be sharp and harder than the suspension spring. The aluminum will be hard enough to keep the spring from cracking , yet soft enough to allow the punch to put a small hole in the spring material that can then be enlarged with a 5 sided reamer.