What type of drill bit do I need too drill through broken socket head cap screws? These are the allen head bolts on the steering brake release mechanism of a Unit 614 crawler shovel. Thank you.
Is there any way you could post a pic of what you're working on? That helps a lot with ideas.
So the head broke off, but you have to remove the rest of the bolt to get something to "slide" because it can't "lift off" of the bolt? Try a cobalt drill bit, go slow and sharpen it often. If that doesn't work, a carbide bit (masonry bit) sharpened a little more will wear it's way through the steel. If you still have access to the head, it might be possible to weld a nut onto the bolt. That will do more to loosen the bolt than just about anything else out there, and the welded head will usually be enough to get it loose.
Welding would be considered if I had more access. As it is I am laying on my back under this dead critter. The two bolts that I am trying to drill to extract have broken off in a recessed position. It would take over an inch of weld to bring them up to the surface of the casting that they are in. And I do not want to "glue" them in place! I will try a cobalt and a masonry bit, HSS bits have just created magnetized dust so far. Did I mention that I am laying on my back underneath this crawler without enough room to even turn onto my side? I would have loved to dig a pit to stand in to work on it, but the crawler is parked on sand that would need to be shored up.
I don't recall who, but somebody makes some left hand twist bolt extraction drill bits. If you get lucky sometimes the drill will spin the bolt out. Socket head bolts I believe are equivalent to grade 8 or better so they are a bugger to drill for sure!
I once drilled through an easy out. Took a handful of cobalt bits, and a variable speed drill would have been nice, but I got through.
Snap on makes a left handed drill bit/ ez out kit. Like lantraxco said sometimes you get lucky and it will spin bolt out. Wilko you should get an award because only a few humans have lived long enough to drill through an easy out.
Snap-on and Fastenal both have left hand drill bits. I'm sure others like Matco, and MAC have them too, but I don't deal with them much. Grade 8's run 150,000 PSI tensile, a SHCS is upwards of 180,000 PSI tensile. Another thing that will eat hard materials(not just bolts, I had a guide pin on a camera that laughed at any drillbits that Fastenal had, carbide masonry bits included) is a good carbide cutter in either a multi-speed drill or a die grinder.
Norseman black and gold bits will drill them out no problem. But you probably work hardened it already
Google Artu drill bits. I always have a couple handy.
Ray, How fast do turn your Artu bits when using them ? I watched a video on YouTube and the man in the video had the bit in a drill press. He said to change the belts to turn the chuck at the fastest speed it would go. I thought the high speed would dull it quickly but apparently it didn't. I need to drill a hole in a hardened steel pin and will purchasing a set of those bits. Here is a link to the video if anyone would like to watch it. https://www.youtube.com/watch?v=zbJq2z2ya80
I spin them fast but not as fast as 4000 rpm they recommend.I always use some coolant. They will drill through a tap or broken drill easy enough. I've often sharpened up masonry drills to do the job but the artu are more reliable.
I have also drilled a easy out that someone broke off & then left that bolt out!!!! the cobalt bits are good but the Artu bits are the cats meow iv also used the carbide tipped bits in an pinch. the important thing is get it started straight with a small bit first( you can drill really hard surfaces with a small bit) then work your way up to a bigger bit!!! GOOD LUCK
Fastenal has left hand drills give them a call in Malone. I use a right angle drill.if it is deep I made some sleeves to find the center. sometimes they come out with a die grinder one chip t a time ,heilcoil is next need something I will be in the white face area 9 july 14 518 470 7499
I use a carbide burr to round out the sharp edges of the bolt head first and then do the drill till dull and resharpen. Once the center is drilled through the bolt usually collapses and the threads will back out. If the bolt is rusted in then I heat and let cool and try to back it out. Good Luck!
Heat will work wonders if you can get enough in there... also depending on the area if you can get enough heat you might try to anneal the grade 8 bolt into something more manageable like a grade 3
If they are broke of in an inch you can also use a bushing to hold the drill centered on the bolt. Good luck and let is know how it goes.
Something triggered a brain cell I thought I had killed back in my drinking days, I don't know if it's still around, but there was an outfit back in the 90's that made a special welding rod, had a semi-ceramic flux jacket or something, for broken bolts/studs. You could stuff it into the hole and the arc would be inside the flux building metal as it slowly filled the hole in, leaving weld metal in the center and a flux tube around the outside. When you got it up flush you welded a nut on and after cooling a while you could usually just spin the offending fastener right out. Pretty slick stuff if you can still find it. Oh yeah, duh, Googled it, it's called: X-Tractalloy
I used that stuff back when all the new JD shovels were breaking rotex bolts. They would break way up inside and never flat enough to get a drill to start. I would slide a piece of pipe into the hole then jam that rod up the middle, then use a pipe wrench to back the pipe out and the bolt would come with it.
Thanks for the information about those bits Ray. I just bought a set of 10 new Artu bits, in the factory blister packs , 1/8 to 1/2 inch for 35.00 US dollars on ebay. Here is a link if anyone is interested in looking at them. http://www.ebay.com/itm/221485150553?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Thanks for the info, just bought my set too.