Installation
Troubleshooting Tips: 1. The Tensioners will not spin onto the stud 2. The stud interferes with the socket or the wrench 3. The flange is not seating evenly 4. The jackbolts don't seem to stabilize 6. The stud stretch measurement is not as expected
1. The tensioners will not spin onto the stud •Verify the correct thread pitch was ordered - If the tensioner spins down less than one thread, the wrong thread pitch may have been ordered. •Clean the threads thoroughly - If the tensioner spins down several threads and gets stuck, the threads may just need a better cleaning. Use a wire brush or wire wheel followed by a soft bristle brush or cloth. If the tensioner still will not spin down: •Check for any deformation of threads. Any thread burrs or galling should be cleaned up with a small file. If the tensioner still will not spin down: •You may need to chase the threads with a die nut. If a stud has been in service for a long period of time, the thread may deform enough to create a pitch error. •You may also try a lapping compound such as "Clover" if the thread interference is minor. Lapping compounds are lubricants with light abrasive additives. Apply the lapping compound to the threads and move the tensioner in a back and forth motion until the thread loosens up. Spin the tensioner down further until it tightens up again and repeat the back and forth motion. Continue making small advances until the tensioner seats against the washer.
2. The stud interferes with the socket or the wrench.
3. The flange is not seating evenly •If it is a circular flange, you should be tightening in a star pattern. •If you are using two workers with two sets of tooling, verify that their tooling is the same. Check one torque wrench against the other. If using air impact wrenches, make sure that the impacts have a similar output. Reference the installation procedure to see how to calibrate the impacts. Verify that the make and model of the tool are the same and that the tools are in similar condition. Also verify that the air pressure to each tool is the same. Each tool should have a dedicated air-line of the same length and diameter to assure an even pressure. Running two tools from one line will likely cause irregular tool output throughout the tightening. •If a specific region on the flange has too large of a gap, an additional tightening round can be applied to the tensioners in that region to close the gap. •If the gap cannot be closed, you may have to disassemble and check for interference such as a pinched gasket or material debris. •For split case turbines or compressors, make sure to follow the manufacturer's tightening sequence. Often, it is required to tighten from the center of the split joint out. If the ends are tightening first, the center may not achieve metal-to-metal contact if the casing has an irregular surface or bow.
4. The jackbolts don't seem to stabilize. I keep tightening around and around. •The stud threads might be pulling out of the female hole if it is a body bound stud. This can occur if the male thread is stronger than the female hole. For example, a stud threaded into a soft casting, or a stud secured into cement or similar for a foundation bolt. Make sure that you are not tightening to an excessive preload. •Make sure that the preload is below the yield strength of the stud. Otherwise the stud will deform and the jackbolts will not stabilize. •If tightening against a shoulder, make sure that the shoulder can carry the load. This involved reviewing the contact area and the yield strength of the material. Preload divided by area = stress. Make sure the stress doesn't exceed material yield strength. •Occasionally, the stud can be bad. This can be identified by measuring the stud elongation. If the stud elongates properly but the jackbolts do not stabilize, the stud may be yielding due to an internal flaw.
•Make sure that you have the correct socket size. Jackbolt hex's come in fractional sizes including 7/32", 9/32", and 11/32", as well as metric sizes. •Use only high quality six point sockets. Twelve point sockets round more easily. •Choose sockets with a deep hex. Superbolt jackbolts have a long hex compared to a standard hex head bolt. Some socket brands have a shallow hex and may engage as little as 50-60% along the hex length. Also check out the deep well sockets as they may have a deeper hex than the standard socket.
6. The stud stretch measurement is not as expected •Verify that you are tightening to the correct jackbolt torque. To do this, you must be able to convert from the original torque or stretch specification. You must know one of the following: IV. Bolt preload A "General Tensioner Installation Sheet" should have been sent with your tensioners. This sheet has information specific to the tensioners it is shipped with, including a jackbolt torque conversion table. From this table, the jackbolt torque can be determined if I, II, III, or IV above are known. If you do not have a copy of this document, please call Superbolt during normal business hours (M-F, 7:30 A.M. - 5:00 P.M., EST) to have a copy faxed to you. •You may also check for a torque stamped on the tensioner nut body. If the tensioner is a standard series product, the torque on the tensioner is a standard rating and may not be appropriate for your application. For an estimated 85-95% of applications, the standard torque does apply. CAUTION! For a very small percentage of applications, the standard torque rating can damage the equipment. In these cases, the weakest link is usually the strength of the components being clamped, not the studs. •If the tensioner is a special design, The torque on the tensioner is usually specific to the application and was determined by an engineer familiar with the application. This should still be verified, however.
1. The jackbolts are hard to remove 2. The socket is "sticking" to the jackbolt hex's and is difficult to remove 3. A jackbolt broke during removal 4. The tensioner is stuck on the stud after all of the jackbolts have been loosened • For tough applications, view our "Alternate Removal Procedure" (PDF) The most common mistake with removal is unloading the jackbolts individually instead of gradually, per the removal procedure. As you loosen any given jackbolt, the load on the remaining jackbolts will increase slightly. It is essential that the jackbolts are turned no more than ¼ turn and that all jackbolts are unloaded gradually. Do not extract the jackbolts individually or you will eventually increase the load on the remaining jackbolts to the point that they could be stuck. You will risk breaking a jackbolt if excessive force is used. •Hydraulic oil or similar can be used to reduce the removal torque required. Apply the hydraulic oil to each jackbolt thread and to the washer. The oil will help to reactivate the jackbolt lubricant. This is especially useful for removal after high temperature service. For inverted applications, apply the oil between the washer and the nut body. For high temperature applications, apply the oil as the equipment is cooling down and reapply as needed to keep the jackbolts wet. From 300°F - 600°F, use synthetic oil such as Mobile 1 to avoid "smoking" of the oil. Below 300°F, standard petroleum based oil can be used. Time permitting, keep the tensioners wetted with oil for a few hours or more. Minimum time should be 30-60 minutes. •If any one jackbolt will not turn, try tightening the two jackbolts on either side slightly over the original installation torque and see if the stuck jackbolt will turn. •Alternative Procedure (PDF format) - If you are still having difficulty after following the above removal recommendations, try the alternative removal procedure.
2. The socket is "sticking" to the jackbolt hex's and is difficult to remove. Either the socket is wearing out or the wrong size socket is being used. Stop and get new sockets before you damage the jackbolt hex.
3. A jackbolt broke during removal •Remove the remainder of the jackbolts and try spinning the tensioner off of the stud with force. Since the tensioners are cylindrical and do not have a hex to grip, a metal disc with a hex can be fabricated and secured to the tensioner body. •If the tensioner will not spin, try cutting the jackbolt tip between the nut body and the washer. •If the jackbolt tip cannot be cut due to a physical obstruction, try heating the nut body with a torch and removing it with force. •Heating rods can be used if the studs are drilled out in the center
4. The tensioner is stuck on the stud after all of the jackbolts have been loosened. •One possibility is that corrosion or oxidation has occurred between the nut and the main stud. The tensioner may only need a slight jolt. Try tapping it with a copper mallet. Since the tensioners are cylindrical and do not have a hex to grip, a metal disc with a hex can be fabricated and secured to the tensioner body. •Another possibility is that the flange is still pushing back. This can happen when two surfaces that are not true to each other are brought together during tightening. Compression of surface gaps, warpage, or gaskets during tightening can result in some of the tensioners becoming loose while tightening neighboring studs. If some of the tensioners are spun down during tightening (although the procedure states not to do this) the flange may still be pushing back on some of the tensioners after the jackbolts are removed. Re-install the tensioners that were removed from the neighboring studs and tighten them until the load is released from the stuck tensioners.
Thank you for using Superbolt products. If you have any questions or need assistance, please call us at: 412-279-1149, or 1-800-345-BOLT (U.S.)
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