In this video I’m going to take a look at a few techniques for removing broken bolts or broken studs which are deep within a hole. So I’ve got a stud in that hole that needs removing we’ve also got a sheared bolt just there that needs removing. If you see that all of these are below the surface. Then on this sump we have actually got a sheared bolt just there. The danger with trying to remove a stud like that or a broken bolt is the fact that the surrounding material is much softer than the bolt itself so obviously this is made from aluminium and the bolt is made from steel so the aluminium is much softer. Before you attempt to remove any broken bolt there are a couple of things that you can do that can make it easier. One of the first things you should do is try to shock it now I’m actually going to use a spring-loaded punch to do this so I’m just going to give that a few gentle taps. If you don’t have a spring-loaded punch like that you can use a traditional punch just give that a few gentle taps with a club hammer and that can help to free the broken bolt. can also apply some heat obviously you have to be careful if you’re using burning gear because you can quite easily melt the aluminium. You can also use some spray penetrant there is a good chance that will help. One thing that you could use is a hinge sighting drill they have a spring loaded part there which exposes the drill bit that will actually prevent the drill bits from catching the side of the material which you are trying to remove the broken bolt from. In sighting drills are normally used like that, you’ll position your hinge where you want it then you can simply use that to drill your pilot holes that will ensure they are dead central. However I’m not going to use it for that I’m going to use that to ensure that I can drill dead in the center of a sheared bolt. Take a look at that one for example you can see that that is in very bad condition if you try to use a normal chance at all of getting it started without drill bit on there you would have no slipping off and damaging the aluminium thread. For the first bolt I’m going to swap the drill bit over and I’m going to use a left-handed drill bit so I’m just going to push that in there I’ll then tighten the grub screw and then I’ll screw that back together. The actual drill bit that I’m using is a bit shorter than the one that I’ve taken out so I’m actually just going to remove the spring from that and that will still centre the drill bit. So if we try that in the end of the shaft you can see that it’s a very good fit and we’re not going to actually damage the internal threads on that. You can of course use a regular right handed drill in a hinge sighting drill but that will then mean that you will need to use a screw extractor afterwards. So I’m now going to flick the drill in to reverse and then we’re going So you can see that the left handed drill bit actually started to bite into that and it actually extracted it from the hole. If we take a look in there you can see that the threads are not damaged at all. A big problem with removing a broken bolt that is deep in a hole is that you don’t want to damage the threads in the surrounding material. I’ve actually made these which are socket head bolts and I’ve actually drilled a hole down the center of those using a lathe and I’ve actually made an M12, M10 and an M8. So we can now take this we can actually screw that into the hole where the damaged or broken bolt is until that is tight and then we can tighten up the nut that will prevent that from coming loose just gently nip that up and again I’m actually going to use a left-handed drill bit. The beauty of a left handed drill bit is that when it bites into the material there’s a chance that it will remove the broken bolt. So I’m just going to put some cutting paste on the end of that and ensure the drill is in reverse You can see that that has now started so I’m going to remove the bolt and we should have an indentation in the bolt so that should ensure that we don’t actually damage the threads on the aluminium and we should now be able to proceed and there is a chance that we will be able to remove this. Let’s give that a spray with some spray penetrant and I’ll just try again. It’s not actually been moving the bolt that time but we have got it far enough forwards now and in a deep enough hole to try a screw extractor. So I’m now going to take a screw extractor I’ll just tap that in there I’m just going to take a small adjustable, I would normally use a a tap wrench but it is at work. This time we’ve actually got that moving. It moves a little bit more, it has actually slipped out again. These are not the best quality screw extractors that you can get these were a very cheap set. I’m just going to go to the next size up. I’m just going to tap that in, and as you can see that has successfully removed the damaged bolt. I’ll just prove to you that none of these threads have been damaged. We can now take an M10 bolt and we can easily screw that back in there. With this one you’ve got absolutely no chance at all of starting the drill bit on it because it’s not at all flat. So the chances are that you’d skid off there and you’d actually end up damaging the threads. So I’m just going to give that a spray. I’m now going to take the socket head bolt that I’ve drilled a hole through the center, I’m going to screw that in there until it touches the broken bolt, I’m going to run the nut down and I’ll just nip that up. I’m going to use a cobalt drill bit for drilling the bolt because these are very tough. What we don’t want to do is go too deep into it because you don’t want to drill into the aluminium. So I’m just going to apply some cutting paste then I’m going to proceed to drill the hole. I’m now going to remove that and we’ll see how deep in we have gone. So you can now see that we’ve got that hole started and it is dead in the center of the bolt. Now that we’ve got the hole started in the dead center we can now continue to drill that without the guide in or if you aren’t confident about doing that you can always put the guide in. So I’m now going to take some more cutting paste and I’m going to proceed to drill the hole. So we’ve drilled approximately seven to eight millimeters in that bolt. What we don’t want to do is go too far in there and go through the actual aluminium casting. So I’m actually just going to try the screw extractor on that now. I’m just going to tap that in using the hammer and then I’m just going to undo that using the adjustable spanner. It does actually look like that has bit. Normally I would use a tap wrench for doing this but unfortunately it is at work. As you can see that has been removed successfully. We will now just try a regular M12 bolt back in there just to prove that the threads have not been damaged. You can see that that goes in there perfectly. Obviously before you go putting any bolts back into components like this it’s a good idea to give them a good coating using some copper grease or anti-seize compound. If you do that you can virtually guarantee that the next time you come to remove the bolts they’re not going to seize up and they’re not going to snap and you will be able to remove them very easily. So that’s a couple of techniques that you can use to remove bolts that have been broken deep in holes. I hope you found this video useful if you have and you haven’t done so already please subscribe to the channel.