The Best Ways to Get Stuck Bolts Out
Heat is Your Friend
- Consider the location of the stuck bolt. If you are close to a gas tank or other flammable substances, a torch is not going to be a viable option. However, heating the metal around the housing of the bolt hole will expand the metal and allow a better chance of extracting the stuck bolt. Use an oxyacetylene torch or even a portable propane torch to heat the metal housing surrounding the bolt. Heating the bolt in addition to the metal will only expand the metal of the bolt as well. This will weaken the bolt when you try to extract it. Point the tip of the flame around the circumference of the bolt head until the surrounding metal glows cherry red. At this point, apply the extracting device--ratchet and socket, wrench, bolt-out socket or whatever else and turn the bolt counterclockwise. The telltale sign you are succeeding is a prominent squeak of the bolt as it complains about being removed. No squeak coming from the bolt most likely indicates it is twisting in the bolt hole and will undoubtedly snap. In that case, you have decreased your chances of a successful extraction significantly. Reapply heat to the bolt that is successfully being extracted from the bolt hole the second you stop hearing it squeak, and then resume backing it out until it is fully extracted.
- Rounding off bolt heads is a common occurrence when attempting to remove a stuck bolt. Now a socket or hand wrench of any size will not fit the bolt head securely enough to extract the bolt. Try pounding on a socket of a smaller size with a hammer to grab the bolt head. If this does not work, bolt-out kits are available and have a high degree of success. The bolt-out sockets employ the same idea as a smaller socket. They integrate reverse flutes inside the socket that help bite into the misshapen head of the bolt. Use the oxyacetylene torch or even a portable propane torch, if possible, before you hammer on the bolt-out socket and attempt to extract the bolt. Do not heat the bolt-out socket or the bolt during this procedure. Before applying the bolt-out socket, use the torch. Heating the bolt-out will damage it and compromise its efficiency.
Drilling and Tapping
- Sometimes, the bolt head has snapped flush, or it has snapped inside the bolt hole. Now your skills will be tested. Drill the remaining bolt out of the bolt hole. Use a left-handed drill bit with the drill in reverse. This helps chase the metal shavings of the bolt outward instead of inward, which will lead to further damage of the bolt hole. Apply thread extraction oil to the drill bit often to help lubricate the bit. Otherwise, the bit will overheat and dull during the extraction. Be sure to stay straight on the center of the bolt. You can also use a sharp punch to direct a pilot hole in the center of the bolt. This helps guide the drill bit into the center of the hole and increases your chances of success. There is no need to employ the torch once this step has begun. The more heat will only compromise the efficiency of the left-handed drill bit. Keep in mind that you must be careful for fully seated bolts. These bolts are the kind that sit inside their respective bolt holes without coming through the end of the component they are affixed to. If you continue drilling beyond their countersink, you could damage the component you are drilling into. Work slowly and remove the drill often to inspect your progress.
- Once you have the bolt out, you will want to replace it. Replacing the bolt without further maintenance to the bolt hole may compromise future repairs on the component you are working on. Use a tap set to match the bolt diameter and pitch that you are going to use inside the extracted bolt hole. Apply lubricant to the tap as you drive it into the bolt hole. This will help it cut new or clean old threads of the bolt hole and increase your chances of installing a new bolt without problems. If you feel resistance when retapping the bolt hole, tighten the tap one revolution and back it off a half revolution. This will help the flutes and threads on the tap to expel the metal shavings down the shaft of the tap and not press them further into the bolt hole. Use a new bolt in the hole and not the one you had to remove--even if you had success removing the bolt intact. A freshly tapped bolt hole and a new bolt will offer you the best chances of removing it again in the future.