ROTATIONAL CAPACITY TESTS

FOR BOLTS TOO SHORT TO FIT TENSION CALIBRATOR

****THIS IS A NEW IM. – PLEASE READ CAREFULLY.****

SCOPE

This IM provides the test procedure for determining the rotational capacity of bolts too short to fit in the tension calibrator. The Rotational Capacity (RC) Test for all high strength fasteners shall be performed in the shop and in the field as required by Standard Specification 2408.03, S.

EQUIPMENT REQUIRED

1. Calibrated torque wrench or equivalent.

2. Spacers and/or washers with hole sizes shall not be larger than 1/16 inch (2 mm) than the bolt being tested.

3. Steel section with an appropriately sized hole to install the bolt. Any available splice hole can be used with a plate thickness that will provide the number of threads under the nut required in Step 1 below.

PROCEDURE

1. Install the bolt into the hole. Install the required number of shim plates and/or washers. One washer under the nut must always be used to cover three to five full threads. A combined total of no more than three shims and washers may be used.

2. Snug the bolt using a calibrated wrench. Snug tight torque shall be between 10% and 20% of the torque listed in Table B2.

3. Match mark the bolt tip, nut, and the plate in a straight line.

4. Tension the bolt by turning the nut using the torque wrench to the rotation listed below. A second wrench must be used to prevent rotation of the bolt head during tightening. Record the torque required when this rotation is achieved. (Torque must be measured with the nut in motion.)

Table B1

Bolt Length

(measured in Step 1)

4 x bolt diameter or less

Greater than 4, but no more than 8 x bolt diameter

Greater than 8 x bolt diameter

Required Rotation

1/3

1/2

2/3

The measured torque should not exceed the values listed below. Assemblies that exceed the listed torque have failed the test.

Table B2

Bolt Diameter (in.)	1/2	5/8	3/4	7/8	1	1 1/8	1 1/4	1 3/8	1 1/2
Torque (ft.-lb.)	150	290	500	820	1230	1500	2140	2810	3690

Table B2M

Bolt Diameter (mm)	13	16	19	22	25	29	32	35	38
Torque (N-m)	203	393	678	1110	1670	2030	2900	3810	5000

5. Tighten the nut further to the rotation required below. The rotation is measured from the initial marking in Step 3. Assemblies fail the test if stripping or fracture occurs.

Table B3