In reply to Ian Parsons:
> (In reply to SteveSBlake)
>
> Indeed - intended for use in hard rock (granite etc, as in this case) they rely on an interference fit rather than expansion. Similar "bolts" were available for softer rock, with a slot and protruding thin wedge in the end - the end of the wedge would abutt the bottom of the hole and expand the shaft, in much the same way that the cone in the old caving "sleeve" bolts expanded the sleeve; I'm not sure whether the manufacturer of the CT gear - Cassin - also produced the expansion version, but they certainly existed.
Hi Ian,
I guess we'll never know their holding power, though they do seem to have come out quite cleanly - In the photos the bolts don't look like they've taken much of a beating to get out, and they look like they're soft steel.
From my armchair I see someone else has mentioned the holes are still there, and if someone's determined enough it would be 'straightforward' (as any steep alpine route in Patagonia!) to re establish it, , or hook it with the occasional bolt for pro?
Regards,
Steve
> They actually look quite long - compared, at least, to the one that I've just dug out of my collection! Mine has a total length of 60mm, of which the shaft contributes only 20mm. Those in the photo appear to have a shaft about the same length as the eye - ie 40mm; that makes them about the same length as the quarter-inch Rawl split-shaft bolts - also "compression", not expansion - that were the standard in Yosemite at the time. The one I'm looking at, however, has an 8mm shaft - 5/16 inch - which suggests that, fully inserted in exactly the right size hole, they might actually be stronger than their contemporaries elsewhere; the "right size hole" bit was probably crucial!