Title:

Spiralock™ Hardware

Number:

PB_572

Release Date:

02/02/2022

Revision Number:

3

Revision Date:

02/05/2025

Chassis Type:

Arrow XT, Velocity, Impel, Saber, Enforcer, Quantum

Component Description:

1/2”, 5/8”, and 3/4” fasteners on chassis

Tools:

See Torque Tool Recommendations

Subject:
Introduction of tri-crimp, Spiralock™ chassis/aerial hardware.
Purpose/Background:
•
•
•
•

Pierce is replacing all 1/2”, 5/8”, and 3/4” Magni-black nuts with tri-crimp Spiralock™ nuts. This change
from oval lock to Tri-crimp Spiralock™ only affects 1/2”, 5/8”, and 3/4” hardware.
Spiralock™ fasteners are being used by Pierce® primarily on frame builds started in October 2021 (RFPs
starting in February 2022).
Spiralock™ nuts look similar to standard hardware but require higher
torque specifications.
Spiralock™ nut threads have a special wedge ramp at the foot of the
thread allowing a continuous line of contact when a clamp load is applied.

Hardware Identification:
Installed hardware is noted on the Aerial placard when
applicable.
NOTE: The Aerial placard will denote what is installed on the
apparatus at time of OEM build. If hardware is loose,
we recommend changing to the Spiralock™ hardware
on both sides and having the placard updated or noted
in the customer’s file.
However, suspension and other areas of installation require
visual inspection during installation and service to determine
appropriate torque values.
(see pictures to right for identification details).

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PARTS BULLETIN #PB_572.2

Description/Procedure:
Spiralock™ nuts have higher torque specifications compared to standard fasteners as shown in the table below.
NOTE: A backing wrench must be used when torquing this hardware.
NOTE: If you have previously installed Spiralock™ nuts you do not need to re-torque to the new values. If you
need to replace a Spiralock™ nut you must torque to the new value.
**DO NOT USE LOCTITE WITH THIS HARDWARE**
Oval Crimp Hardware

Spiralock™ (Tri-Crimp) Hardware

Nut Size

Part Number

SOP Torque

Part Number

Old Torque

New Torque as of 06/07/2023

1/2"

82-3009

85 lb-ft

3665096

130 lb-ft

113 lb-ft

5/8"

82-3010

180 lb-ft

82-4065

250 lb-ft

250 lb-ft

3/4"

82-3011

285 lb-ft

82-4066

450 lb-ft

424 lb-ft

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PARTS BULLETIN #PB_572.2

These new torque values can also be found in our chassis operators manuals in the maintenance chapter under
Frame Fasteners and in our service manuals under the Fastener Identification, Torque Specifications & Locking
Mechanisms chapter.
Aerial Torque Box Application: All Aerials and Tillers, Excluding New 100 AAT (Ascendant Aerial Tower)
If determined to replace just 1 magni-black nut with the tri-crimp Spiralock™ nut on the torque box, then you
MUST change all Torque Box hardware to the tri-crimp Spiralock™ along with ordering a new Data Placard to
reflect the new Torque Value of the changed hardware on the Torque Box.
NOTE: Data Placard can be ordered through Pierce Parts Team.
Torque Tool Recommendations:
The following tools have been identified for better access to hard-to-reach
hardware. It is critical that you use a backing wrench at all times. These may
be found locally or online.
Part Number
4667271
4666815

Description 1
KIT, TORQUE WRENCH,
150-800 NM
WRENCH, TORQUE, 150800 NM

4666818

TORQUE WRENCH HEAD

4666820

TORQUE WRENCH
HEAD, STEEL

Description 2
2 HEADS WITH 1.125 IN
DRIVE
INTERCHANGEABLE
HEADS
1.125 IN SQR DRIVE, 5.75
IN L
1.125 IN DRIVE, 3.9375 IN
L

NOTE: Currently installed hardware is not defective. You do not have to change all hardware to the Spiralock™.
It is suggested, during periodic inspections, if hardware is loose, you may choose to replace the nut (new
part number) and the bolt (original part number) to minimize future serviceability.
If any additional support is needed, please open a technical support incident on Pierceparts.com.
Revision Log
Rev. #
3

Changes

Date

Updated formatting and Torque Tool Recommendations

2 6 00

AMERI CAN

DR I VE

•

APP L ETON,

W I

54 91 2-2 0 17

02/05/205

•

920 - 83 2- 30 00