I'm doing some work on my old Cat 943 (circa 1983) that involves drilling out some snapped bolts. These are the original Cat bolts and they've been snapped in there since Adam was driving it through the apple trees! Now, I'm old truck mech from way back and have sharpened my own twist drills for years but these bolts are "something else"
They're 1/2 inch UNC and I can get 3/32 drill down the centre of the bolt after three "sharpenings". A 1/8th went down as well, using the 3/32 as a pilot. Next was 3/16 which chewed the cutting edges off quickly. Next a 1/4 drill won't even get past the start tip of the drill!
Is this simply a case of work hardening of the steel bolt or are Cat bolts case hardened to a depth of say 1/2 of the bolt diameter.
PS - it looks like a gas axe is the only way these are gonna come out!
Thanks,
AG
They're 1/2 inch UNC and I can get 3/32 drill down the centre of the bolt after three "sharpenings". A 1/8th went down as well, using the 3/32 as a pilot. Next was 3/16 which chewed the cutting edges off quickly. Next a 1/4 drill won't even get past the start tip of the drill!
Is this simply a case of work hardening of the steel bolt or are Cat bolts case hardened to a depth of say 1/2 of the bolt diameter.
PS - it looks like a gas axe is the only way these are gonna come out!
Thanks,
AG
Caterpillar bolt grading??
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