Installation Tips

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
5. The sockets are rounding
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.

•If the stud extends through the nut body, it may interfere with the socket or the wrench when trying to tighten. Tooling options include finding a socket that has a smaller diameter that will fit, or using an extension. Another option may be to add a spacer beneath the Superbolt hardened washer to raise the tensioner to the end of the stud. If the stud is a through-stud, the extra stud length can often be threaded through the standard nut on the other side of the flange.

 

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.

•Something is still moving. Either the clamped connection is moving or the stud is stretching. Possibilities are listed below.

•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.

 

5. The sockets are rounding

•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:
I. The original nut torque, or
II. The original stud stretch and the bolt effective length, or
III. The OEM specified stud stress

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.