Wire Inserts

Wire_Thread_Insert_Installation.pdf (127.23 KB)

Wire Thread Insert Overview

Spiralock wire thread inserts are helically-coiled fastening devices that provide permanent, wear resistant screw threads that exceed the strength of most parent material; the inserts are designed to protect tapped holes against failures due to stripping, seizing, corrosion, and wear. Spiralock inserts are unlike any other wire thread insert for the fact that our inner diameter wire geometry incorporates our 30° wedge ramp thread form design. Our wire thread inserts are available in two styles: tanged and Drive Notch (DN™), egineered with no tang.
Crest of bolts seats against ramp of Spiralock insert thread profile, preventing transverse movement of bolt relative to insert, thus resisting loosening due to vibration.
Standard Thread InsertSpiralock Thread Insert
 

Features of the Spiralock wire thread insert:

Benefits of the Spiralock wire thread insert:

  • Threads into (Screw Thread Insert) STI holes per NASM33537
  • Accepts standard 2A/3A bolts (4g6g and 6g)
  • Replaces Helicoil® locking inserts
  • Spiralock insert meets or exceeds the applicable parts of NASM8846, e.g. the wire tensile strength, chemical composition, and methods of inspection.
  • Spiralock insert is not a prevailing torque type screw-locking insert - no risk of galling or seizing of bolt & insert
  • Similar to NASM1130 inserts
  • Provides proven superior vibration resistance to standard locking inserts
  • Duplicates a Spiralock® tapped hole
  • Combines the advantages of wire inserts with the vibration resistance and load distribution of Spiralock
 

Advantages of the Spiralock Drive Notch (DN™) insert:

  • Speeds installation and reduces labor costs due to elimination of breaking off tangs, their retrieval, and accounting for them
  • Eliminates the potential of foreign object damage (FOD-free design) or short-circuiting of electronics by loose tangs
  • Prevents harm to expensive castings by invasive tang removal techniques
  • Eliminates messy and environmentally unfriendly chemicals or adhesives
  • Competitively priced as compared to conventional inserts
 

Performance and Features

Spiralock inserts are made of cold-rolled Type 304 stainless steel wire (AS7245), work-hardened to a tensile strength above 200,000 psi, having a hardness of Rc43-50. The finished surface (8-16 micro inches) is exceedingly smooth, virtually eliminating friction-induced thread erosion.

It is important to select the proper insert length in order to balance the bolt tensile strength against the shear strength of the parent material. The insert lengths are calculated numbers because the inserts cannot be measured in the free state. The lengths are multiples of the nominal thread size, or diameter, of the insert. Please see Table III for insert dimensions. Using the insert length selection table below, an insert length can be selected which will produce a thread system strong enough to fracture a bolt before it will strip or damage either the parent material or the insert.
Recommended Nominal Insert Lengths Based on Parent Material Versus Bolt Material Strengths

Unified


Shear Strength

of Parent

Material (KSI)

 


Bolt Material Minimum

Ultimate Tensile Strength (KSI)

 

54

 

75

 

96

 

108

 

125

 

132

 

160

 

180

 

220

10

2

2-1/2

3

-

-

-

-

-

-

15

1-1/2

1-1/2

2

2-1/2

2-1/2

3

3

-

-

20

1

1-1/2

1-1/2

2

2

2

2-1/2

3

3

25

1

1

1-1/2

1-1/2

1-1/2

2

2

2-1/2

2-1/2

30

1

1

1

1-1/2

1-1/2

1-1/2

2

2

2-1/2

40

1

1

1

1

1

1-1/2

1-1/2

1-1/2

2

50

1

1

1

1

1

1

1

1-1/2

1-1/2

Metric


Shear Strength

of Parent

Material MPa

(Alum., Mag., Steel)


Bolt Material Minimum

Ultimate Tensile Strength MPa

 

300

 

400

 

500

 

600

 

800

 

1000

 

1200

 

1400

70

1-1/2

2

2-1/2

2-1/2

-

-

-

-

100

1

1-1/2

1-1/2

2

2-1/2

3

-

-

150

1

1

1-1/2

2

2

2

2-1/2

3

200

1

1

1

1

1-1/2

1-1/2

2

2-1/2

250

1

1

1

1

1

1-1/2

1-1/2

2

300

1

1

1

1

1

1-1/2

1-1/2

1-1/2

350

1

1

1

1

1

1

1-1/2

1-1/2

The resilient characteristics of each coil in the Spiralock insert allows it to adjust independently to secure the maximum surface contact with individual threads in the parent material. As a result, loads are distributed more evenly. Each coil can flex independently to contact the greatest amount of parent material thread surface. Stress and fatigue concentrations are reduced to maximize thread strength and increase the reliability and life of the fastening system. Once installed, the outward spring-like force of the coils holds the insert into place. Furthermore, when the bolt is screwed into the insert and torque is applied, the crests of the bolt will push radially outward on the 30° ramp of the insert’s Spiralock thread form. The insert will transfer the energy outward into the parent material thereby locking the insert into the material.

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Wire Thread Insert Dimensions


Table III



Nominal Thread Size


Nominal Length*


Free Outside Diameter


Number of Free Coils

 

 

Length of Insert (in Diameter)

 

Nominal Length (Diameter)

 

 

1

 

1 ½

2

2 ½

3

Min

Max

1

1 ½

2

2 ½

3


Unified sizes

 

2 (.086) -56

0.086

0.129

0.172

0.215

0.258

0.11

0.119

3

5-1/4

7-3/8

9-5/8

11-7/8

4 (.112) -40

0.112

0.168

0.224

0.280

0.336

0.144

0.159

2-3/4

4-3/4

6-3/4

8-7/8

10-7/8

6 (.138) -32

0.138

0.207

0.276

0.345

0.414

0.178

0.193

2-3/4

4-3/4

6-7/8

8-7/8

10-7/8

8 (.164) -32

0.164

0.246

0.328

0.410

0.492

0.205

0.220

3-1/2

6

8-3/8

10-3/4

13-1/4

10 (.190) -32

0.190

0.285

0.380

0.475

0.570

0.236

0.256

4-1/8

6-7/8

9-1/2

12-1/4

14-7/8

1/4 (.250) -20

0.250

0.375

0.500

0.625

0.750

0.310

0.330

3-3/8

5-3/4

8

10-3/8

12-3/4

1/4 (.250) -28

0.250

0.375

0.500

0.625

0.750

0.306

0.326

5

8-1/4

11-3/8

14-1/2

17-5/8

5/16 (.3125) -18

0.312

0.469

0.625

0.781

0.938

0.380

0.400

4

6-5/8

9-1/4

11-7/8

14-5/8

5/16 (.3125) -24

0.312

0.469

0.625

0.781

0.938

0.380

0.400

5-1/2

8-7/8

12-1/4

15-5/8

19

3/8 (.375) -16

0.375

0.562

0.750

0.938

1.125

0.452

0.472

4-3/8

7-1/4

10

12-7/8

15-3/4

3/8 (.375) -24

0.375

0.562

0.750

0.938

1.125

0.448

0.468

6-7/8

11

15

19-1/8

23-1/8

7/16 (.4375) -14

0.438

0.656

0.875

1.094

1.312

0.526

0.551

4-1/2

7-3/8

10-1/4

13-1/8

16-1/8

7/16 (.4375) -20

0.438

0.656

0.875

1.094

1.312

0.524

0.549

6-5/8

10-5/8

14-5/8

18-1/2

22-1/2

 

Metric sizes

 

M3X0.5

3.0

4.5

6.0

7.5

9.0

3.80

4.35

3-3/4

6-3/8

8-7/8

11-3/8

13-7/8

M4X0.7

4.0

6.0

8.0

10.0

12.0

5.05

5.60

3-5/8

6-1/8

8-5/8

11-1/8

13-5/8

M5X0.8

5.0

7.5

10.0

12.5

15.0

6.25

6.80

4-1/8

6-7/8

9-5/8

12-3/8

15-1/8

M6X1

6.0

9.0

12.0

15.0

18.0

7.40

7.95

4

6-3/4

9-1/2

12-1/8

14-7/8

M8X1.25

8.0

12.0

16.0

20.0

24.0

9.80

10.35

4-1/2

7-3/8

10-1/4

13-1/4

16-1/8

M10X1.5

10.0

15.0

20.0

25.0

30.0

11.95

12.50

4-7/8

8

11-1/8

14-1/4

17-3/8

M12X1.75

12.0

18.0

24.0

30.0

36.0

14.30

15.00

5

8-1/4

11-1/2

14-5/8

17-7/8

M16X2

16.0

24.0

32.0

40.0

48.0

18.90

19.60

6-1/8

9-3/4

13-1/2

17-1/4

21

 

* Nominal length is a calculated number and cannot be measured in the free state. It is the actual installed length plus ½ pitch.

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Wire Thread Insert EDP Numbers

Spiralock wire thread inserts are made of cold-rolled Type 304 stainless steel and are supplied unplated, unless specified otherwise. Dry Film lube (per AS5272, Type I) can be requested by adding a 352 suffix to the basic EDP number.



Ordering Code

EDP Number

Insert Type

Plating

Size and Length
See Chart #1

Drive Notch** (DN) or tanged (no suffix)


See Chart #2

 

CHART #1 – EDP Numbers

Size

1 Dia.

1.5 Dia.

2 Dia.

2.5 Dia.

3 Dia.

M3x0.50

97500

97501

97502

97503

97504

M4x0.70

96650

96651

96652

96653

96654

M5x0.80

96700

96701

96702

96703

96704

M6x1.00

96750

96751

96752

96753

96754

M8x1.25

96800

96801

96802

96803

96804

M10x1.50

96850

96851

96852

96853

96854

M12x1.75

96900

96901

96902

96903

96904

M16x2.00

97150

97151

97152

97153

97154

2-56

96010

96011

96012

96013

96014

4-40

96020

96021

96022

96023

96024

6-32

96070

96071

96072

96073

96074

8-32

96000

96001

96002

96003

96004

10-24

96050

96051

96052

96053

96054

10-32

96100

96101

96102

96103

96104

1/4-20

96150

96151

96152

96153

96154

1/4-28

96200

96201

96202

96203

96204

5/16-18

96250

96251

96252

96253

96254

5/16-24

96300

96301

96302

96303

96304

3/8-16

96350

96351

96352

96353

96354

3/8-24

96400

96401

96402

96403

96404

7/16-14

96450

96451

96452

96453

96454

7/16-20

96500

96501

96502

96503

96504

CHART #2 – Plating Options

 

Unplated (if plating option not specified)

301-

Cadmium per QQ-P-416, Type II

310-

Silver per AMS 2410

337-

Passivation - ASTM A967

352-

Dry Film Lubricant per AS5272, Type I

*Tanged inserts are only available in bulk packaging; Drive Notch inserts

**Please call for size availability of Drive Notch wire thread inserts


Example: 96070DN352 #6-32 x 1 dia. long, Dry Film lube coating, Drive Notch style

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