A question about broken cobalt drill bit

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Not welding related, but am installing a fifth wheel hitch in my GMC truck, turns out I have at least two spots where the frame has two layers, and of course first go the cobalt bit broke flush with frame, so wondering, can I use a carbide burr in my die grinder to chew it out, or what, do not want to use my torch on the area in case it affects the frame strength, now this is a 1/4" drill as I was doing the pilot hole before I drill the 1/2" hole I require for the brackets.Any idea the best approach to get this broken bit out?Just started to poke through other side of frame, but it is not far enough in to drive it through, so thought I would ask your opinions.This is probably closest to the burr I bought to try.This is before I started drilling, you can see the weld line joining the frames together.Last edited by partsman; 04-11-2015 at 12:18 PM.
Reply:On the side where it started to break through, either grind the spot larger or bang it in somewhat with a punch of some sort.  Maybe you can then push the broken drill back out just enough to get hold of it.  Or at least dislodge it enough to get some small needle nose pliers in the flutes."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I would use a Cutting torch and blow it out or sometimes a needle nose pliers you can stick the points in and spin it outMillermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:I will back the strike idea. It should break up pretty quick.
Reply:Most of the strength of a beam is in the flanges so do whatever you want in the web.  The web thickness only gives the flanges mechanical advantage against bending which makes the beam stiffer.  The torch is probably your best bet.
Reply:ditto on that idea !!!!!!!!!!!!!!
Reply:Originally Posted by partsmanJust started to poke through other side of frame
Reply:Hammer and punch is definitely the first thing to try.  First see if it will pop out if you hit it from the back.  If that doesn't do it use the punch at an angle to tap the bit counter clockwise from the front.