Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 1 of 12

­ (https://www.facebook.com/AppliedBoltingTechnology) CALL US (TEL:802-460-3100)

(index.html)

BOLTING METHODS

TURN-OF-NUT BOLTING
METHOD
AISC & RCSC Turn-of-Nut (Part Turn)
Note: As with every bolt pretensioning method, Turn-of-Nut may only be

performed after all steel plies in a connection have been drawn into firm

contact, i.e. snug-tightened. Failure to do so will result in inadequate bolt

pretension and loose connections. Also, The Pre-installation Verification

fastener testing must be conducted per applicable RCSC sections with the

caveat that Turn-of-Nut verification may not verified by Direct Tension

Indicator verification (RCSC 48).

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 2 of 12

Turn-of-Nut is performed by rotating the nut or bolt of a fastener assembly a specific turn angle based on the

fastener's length, and diameter while restraining the unturned element from rotating.

Installation - How to perform Turn-of-

Nut on a single fastener assembly:
Determine the ratio between the fastener's length and diameter as well as the slope disposition of the
outer steel plies.
Apply the specified turn from the appropriate table, while the unturned element is restrained from
rotation (usually requiring a second installer).
Rotation exceeding the table below may not be corrected or reworked except by replacing the fastener
assembly.

For reference, table 8.2 from the Research Council on Structural Connection's (RCSC) Specification for Structural

Joints Using High Strength Bolts (http://www.boltcouncil.org/files/2009RCSCSpecification.pdf), 2014, appears

below:

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 3 of 12

Inspection
The inspector must:

1. Verify pre-installation verification has been performed.

2. Verify the joint has been snug-tightened.
3. Verify the original position of all elements.
4. Routinely witness the installation crew actually turning the nuts/bolts.
5. Verify the final rotated position of all elements.
6. Prohibit excessive rotation discovered or witnessed from being adjusted to reflect turn values from table
8.2.

While it is recommended that the bolt, nut, and steel be marked and inspected prior to Turn-of-Nut

implementation, this step is not mandatory. In any case, failure to inspect nuts in their original (snug), un-turned

position will result in unverifiable Turn-of-Nut execution. Nut marking does not relieve an inspector's responsibility

to inspect the connection twice, before and after the turn.

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 4 of 12

Advisories:
Ineffective for some bolts, The Guide:

Users of large diameter high-strength bolts, especially A490 bolts, should be

aware that the RCSC specification requirement for installation of short grip

bolts may not produce the required preload [pretension]. If such bolts are to be

used in a slip-resistant joint [i.e., slip critical and pre-tensioned], calibration

tests in a load-indicating device are advisable. (Kulak 59)

Hot Dipped Galvanizing, RCSC:

Some problems with the turn-of-nut pretensioning method have been

encountered with hot-dip galvanized bolts. (RCSC 60)

Bolt Lubrication too effective or absent, RCSC:

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 5 of 12

Specification requirements for minimum turns testing of galvanized fasteners.

Job-site testing in the tension calibrator demonstrated that the lubricant

reduced the coefficient of friction between the bolt and nut to the degree that

"the full effort of an ironworker using an ordinary spud wrench" to snug-

tighten the joint actually induced the full required pretension. Also, because the
nuts could be removed with an ordinary spud wrench, they were erroneously

judged by the inspector to be improperly pretensioned. Excessively lubricated

high-strength bolts may require significantly less torque to induce the specified

pretension. The required pre-installation verification will reveal this potential

problem.Conversely, the absence of lubrication or lack of proper over-tapping

can cause seizing of the nut and bolt threads, which will result in a twist failure

of the bolt at less than the specified pretension. (RCSC 61)

RCSC section 9.1 snug-tightened inspection criteria flawed:

RCSC section 9.2.1 requires the inspector to witness one element being rotated relative to the other. If not,

improper tension may result if an installation crew only applies the minimum amount of snug-tightening per

section 9.1, Snug Tightened Joints:

9.1 ...It shall be determined that all of the bolts in the joint have been tightened

sufficiently to prevent the turning of the nuts without the use of a wrench. No

further evidence of conformity is required for snug-tightened joints.

If only hand tightening is used as a snug inspection criterion, it is possible for Turn-of-Nut’s initial starting point,

(i.e. adequate snug) will not be achieved and the method will fail. Such failures will not depend on whether

fasteners were marked or not.

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 6 of 12

Canadian Institute of Steel

Construction, i.e. CISC, Turn-of-Nut
Installation:
The CISC Turn-of-Nut installation method is similar to AISC/RCSC Turn-of-Nut with a few exceptions.

1. Required turn values are the same when both faces normal as well as when one face is sloped 1:20.
2. 3/4 turn to be applied to all instances, when both faces sloped 1:20.
3. The acceptable rotation tolerance is ±30°.
4. Beveled washers are required when either steel ply is sloped 1:20 Max when using ASTM A490 and A490M
bolts.
5. CISC Turn Table 8 does not limit itself to 12” maximum bolt length, as the RCSC does.
6. When both surfaces sloped 1:20 max, all bolts rotated 3/4 turn (RCSC requires length dependent turn
values).

For a complete turn details, please refer to the Nut Rotation from Snug-Tight Condition table within the latest CISC

Handbook of Steel Construction.2

Inspection:
The inspector must:

1. Verify pre-installation verification of all assemblies has been performed.

2. Verify the joint has been snug-tightened.
3. Verify the original position of all elements.
4. Verify the final rotated position of all elements.
5. Routinely witness the installation crew actually turning the nuts/bolts.
6. Prohibit excessive rotation discovered or witnessed from being adjusted to reflect turn values from the
applicable table within the CISC handbook.

While it is recommended that the bolt, nut, and steel be marked and inspected prior to Turn-of-Nut

implementation, this step is not mandatory. In any case, failure to inspect nuts in their original (snug), un-turned

position will result in unverifiable Turn-of-Nut execution. Nut marking does not relieve an inspector's responsibility

to inspect the connection twice, before and after the turn.

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 7 of 12

CISC Advisories:
See advisories for AISC & RCSC.

Additional Advisories:
While the CISC does not specifically require Pre-installation Verification testing of all fasteners when using Turn-of-

Nut per se, testing is recommended to assure hardware compliance with the appropriate ASTM Specification.

Thread failure (stripping) will not be discernible otherwise.

Figure 1: Ideal marking technique clearly indicating 1/3rd turn, However, the three bolts on the left
are ready for initial inspection; the three on the right appear turned but it is impossible to know if
they were turned or marked to appear turned.

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 8 of 12

Figure 2: These four nuts appear to have been turned although the exact angle is not obvious since
the lines extend completely through the bolts' diameters. Nevertheless, without inspection of their
initial position, turn or whether the joint was properly snug-tightened, induced pretension cannot be
verified.

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 9 of 12

Figure 3: Obvious deception attempt. While markings suggest each nut or bolt has been rotated, the
nut appears to be in its initial position suggesting bolt rotation. It is unlikely the bolts were rotated
relative to the nuts since the washers are under the nuts, meaning the hex heads of the bolts would
need to be rotated directly against the painted steel surface. A difficult endeavor, that would be
exaggerated by the additional effort required to perform proper Turn-of-Nut in the first place. The
gap along the upper flange also implies incomplete snug-tightening.

(durasquirters.php)

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 10 of 12

BOLTING METHODS

Turn of Nut (Part Turn) 

Calibrated Wrench 

Direct Tension Indicator 

Twist-Off Bolts 

(durasquirters.php)

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 11 of 12

ABOUT APPLIED BOLTING TECHNOLOGY PRODUCTS (ABOUT.PHP)

CONTACT US (CONTACT.PHP)

LATEST NEWS

Dacromet Coating to be Phased Out (news.php) Applied Bolting Technology has been notified by our
suppliers that the proprietary dip-spin coating system commonly known as Dacromet® has reached it's
"End of Life"...

MADE IN AMERICA

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018
Turn-of-Nut Bolting Method | Applied Bolting Technology Products Page 12 of 12

Home (/) | Company (about.php) | Products (durasquirters.php) | DTI Technical Support (instructions.php) |

Bolting Resources (turn-of-nut-dsq.php) | Dealer Locator (dealers.php) |

Distributor Login (BETA) (http://portal.appliedbolting.com)

©2016 Applied Bolting Technology via Conscio Web (https://www.conscioweb.com) | DuraSquirt DTIs, Squirter

DTI's & Squirters DTI are Registered Trademarks of Applied Bolting Technology Products

https://www.appliedbolting.com/turn-of-nut-dsq.php 1/8/2018