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
Try an Artu drill bit
Mitch, Thanks for the reply and the advice therein. These bolts aren't crucial and there are other ways around securing the idler/yoke guards on, plus two of the three bolts per side are OK to use. I can even tack weld the guards on if I have to. But my curiousity was aroused about how the apparently normal high tensile steel bolts came to be so hard. It's almost as if they've been deliberately case hardened!! Weird? Thanks again, AG
CAT bolts are in my experience better than grade 8, or 10.9 on the metric scale. No quite up to Premier Supertanium or aircraft quality I guess, but pretty stout stuff.
Had a girlfriend like that...........
If you have a welder and can weld a nut on the snapped off part... The trick works wonders!
Heat the bolt up and melt a wax candle down the threads. It also works wonders.
A little pricier but I use beeswax instead of a candle. "God's penetrating oil" I call it. Stuff works wonders. I've been using it for years and it still amazes me some of the trash that comes out using that and little heat.
I remember Cat used to have an advertisement in one of the contractor's magazines about how all of their bolts were Grade 8, (strongest available at the time) so there would be no mixups on the assembly lines.
The wax trick Nice posted works wonders! He saved me a huge amount of trouble, time, and money with that one not too long ago. I found several of the bolts in my 953 seemed extremely hard and ate bits. Try the wax trick and you can prolly just back em out. Slickest thing I'd seen in a long time John