Here is my video taking you through how to use a screw extractor step-by-step: I once used an easy out kit to remove a snapped bolt on the undercarriage of a Chinook Helicopter, 300 miles North of the Arctic Circle (This was nothing to do with me over-tightening the bolt this time it was the -25 degrees Celcius temperatures which were placing every component under stress and equipment failures were common.) When used correctly they are simple and effective. I have been using screw extractor sets for many years after first learning about them during my apprenticeship as a mechanical technician in the Royal Air Force, where I served as a technician on aircraft for 7.5 years. So off the cylinder head came again (oh what fun!). The torque wrench failed to ‘break’ at the desired torque, and as a result one of the head bolts snapped in between the cylinder head and the engine block. Unfortunately, I chose to use a very cheap torque wrench to tighten the head bolts up to the required 70 N m. I had already done this once before, so I wasn’t too concerned about the job. The backstory behind this post and my video is this: I was working on an engine and after completing the work the time came for me to refit the cylinder head to the engine block. Once the torque applied exceeds the breakaway torque of the fastener, the fastener will rotate and unscrew.It is best to apply torque evenly, and the kind of handle that you would find in a tap and die set is ideal The screw extractor will attempt to thread itself into the hole and a huge amount of friction is generated between the screw extractor and the broken fastener. Apply torque in an anti-clockwise direction.Place the screw extractor in the hole, and hit it once with a hammer.If you have chosen a larger diameter screw extractor then start off using a small drill bit and then progressively open out the pilot hole you made until you have appropriately sized hole.) The larger you go the less likely it is that you will snap the screw extractor when you apply torque. Using a small diameter drill, drill down into the broken fastener, being careful to stay centred and going deep enough to avoid the screw extractor bottoming out in the hole (The size of screw extractor to use depends on the size of the fastener, and the estimated torque required to break it free.Hold the centre punch in position and hit once with a hammer. Pick up the mark you just made with a centre punch.Mark the centre with an engineers scriber.Make a flat surface in the middle of the snapped portion using a hand file, angle grinder, dremel tool or similar.Here are the steps required to use a screw extractor set: I made a step-by-step video to show you exactly how you can use an easy out to remove a fastener on which the head has snapped off. Use a bit that is smaller than the thread size, otherwise you'll strip the threads so you won't be able to put another screw back in.In this post I show you exactly how to use a screw extractor set to remove a broken head bolt from an engine. You can drill right into the middle of the screw itself (with your drill in reverse), and the bit should actually come out before you've gotten all the way into it. The next thing beyond this is to use a "reverse drill bit" or " left-handed bit". This can be difficult - not deep enough, and you'll just strip the screw worse trying to get it out, and too deep and you'll weaken the head so much it'll probably snap off when you try to turn it. If you can't get the tip out (or don't want to risk trying), I would probably use a dremel cutting wheel, and basically turn the screw into a slotted screw. You may be able to use a small drill bit to extract the broken extraction bit, and then try again - but be careful as you may damage the screw beyond my next tip. If you see any corrosion or rust, or suspect it's needed and have time, this never hurts to do. Hindsight is 20/20 of course, but it would have been good to do this first. I would first use a penetrating oil (though WD-40 might also work), and let it sit for awhile, before trying anything further. The fact it broke off means the screw is probably very stuck.
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