HI ALL
Please note - I haven't posted seeking scrutiny or speculation, just honestly seeking help as I know it can be done.
I've seen some posts whereby people have drilled and tapped / installed time-serts into 1970/71 drive flanges (part no. 90133220922) to conver the 2 rolled pin holes to M10x1.5 threaded holes to receive CV bolts.
Attached are a couple of photos I've located for reference.
I've spent much time seeking to understand if these flanges are through hardened or case hardened and what is actually required to drill them.
It is obvious a standard HSS drill bit won't work - we briefly tried in a friends mill.
So my questions if anyone is able to provide response from experience;
- Does anyone know what the actual hardness is, and if they are through hardened or case hardened?
- Will an M35 or M42 cobalt (5% cobalt or 8% cobalt) drill bit work?
- Or is a solid carbide drill bit required?
- Will a cobalt tap work?
Sincere thanks!
