Pete.
Member
- Messages
- 14,136
- Location
- Kent, UK
What you need is to find an OEM application that uses fine pitch csk.
Could be the reason they are so rare is that the clamping force of a fine pitch is higher than coarse pitch so the load on the taper is enough to overwhelm the torque capacity of the reduced-size hex driver, but that's just speculation on my part.
I'd go with helicoil and coarse pitch bolts. If I absolutely had no choice I would source hex heads bolts, turn them down to the correct csk shape and rotary broach a hex socket in the end.
Could be the reason they are so rare is that the clamping force of a fine pitch is higher than coarse pitch so the load on the taper is enough to overwhelm the torque capacity of the reduced-size hex driver, but that's just speculation on my part.
I'd go with helicoil and coarse pitch bolts. If I absolutely had no choice I would source hex heads bolts, turn them down to the correct csk shape and rotary broach a hex socket in the end.