CW-DSB: Double Upset Spool Bolt HDG

A double upset spool bolt is a pole line fastener used with spool insulators for side-of-pole installation.

Unlike a standard straight bolt, the double upset design incorporates two formed collars that create additional clearance between the pole and spool insulator.

The collars are forged rather than welded. Therefore, the bolt maintains an integral structure without relying on welded collar joints.

You can use this type of spool bolt in overhead power distribution, utility pole construction, and other pole line hardware systems that require a secure spool insulator attachment.

Key Features

1-5/8″ Insulator Offset

The double upset structure provides approximately 1-5/8″ clearance from the pole, allowing you to position the spool insulator away from the pole surface.

Forged Collars

We form the collars as part of the bolt instead of welding separate components onto the shank.

This construction provides a strong and consistent structure for utility pole applications.

Hot-Dip Galvanized Finish

The hot-dip galvanized coating helps protect the steel components against corrosion during long-term outdoor installation.

For projects with specific coating thickness or galvanizing standard requirements, send us your specification before ordering.

Complete Hardware Set

The standard spool bolt assembly includes:

• 5/8″ round washer
• 5/8″ regular square nut
• Cotter pin
• 5/8″ concave square locknut
• Additional regular square nut

This complete configuration helps reduce the number of separate components you need to source.

Multiple Shank Lengths

Standard models include:

• 5/8″ × 9″
• 5/8″ × 10″
• 5/8″ × 12″

Other sizes can be manufactured according to your drawing, sample, or project specification.

Double Upset Spool Bolt Specifications

Mechanical Data

Tensile Strength: 13,550 lbs
Recommended Torque: 15 ft-lb
Offset from Pole: 1-5/8″
Thread Diameter: 5/8″

Specifications can be customized or confirmed according to your project drawings and technical requirements.

Where Do You Use a Double Upset Spool Bolt?

You mainly use a double upset spool bolt together with a spool insulator on the side of a utility pole.

Typical applications include:

• Overhead electrical distribution lines
• Wood utility poles
• Pole-mounted spool insulators
• Secondary distribution systems
• Service drop support points
• Pole line construction and maintenance

The offset structure creates clearance between the insulator and pole while the bolt provides a secure mounting connection.

Double Upset Spool Bolt vs. Single Upset Spool Bolt

The main difference lies in the collar configuration and the resulting mounting position.

If you are not sure which type fits your pole line design, send us your drawing or existing sample. We can help you compare the dimensions before production.

Why Use Hot-Dip Galvanized Spool Bolts?

Pole line hardware remains outdoors for many years. As a result, moisture, rain, temperature changes, and other environmental conditions can accelerate corrosion on unprotected steel.

Hot-dip galvanizing forms a zinc coating on the steel surface and improves outdoor corrosion protection.

Therefore, an HDG spool bolt is suitable for many utility pole and overhead line applications.

If your tender or utility project specifies an ASTM, ANSI, coating thickness, or other technical requirement, include it with your RFQ so we can confirm production capability before quotation.

How to Choose the Correct Spool Bolt Size

Before ordering, confirm the following information:

Thread Diameter

The standard model uses a 5/8″ thread.

Pole and Installation Dimensions

Check the required shank length according to the pole thickness and installation arrangement.

Standard options include 9″, 10″, and 12″ shank lengths.

Required Insulator Clearance

Confirm whether your installation requires the 1-5/8″ offset provided by the double upset design.

Spool Insulator Size

Make sure the bolt dimensions match the spool insulator and related mounting hardware.

Project Standard

If your utility, contractor, or tender requires a specific standard, drawing, mechanical test, or galvanizing requirement, send the complete specification before ordering.

Quality Control for Double Upset Spool Bolts

For bulk utility hardware orders, dimensional consistency matters as much as appearance.

During production, key inspection points can include:

• Steel raw material
• Bolt diameter
• Shank length
• Thread dimensions
• Forged collar position
• Overall length
• Hardware assembly
• Galvanized surface
• Mechanical performance
• Packing and labeling

For customized or project orders, inspection requirements can be confirmed before mass production.

Why Choose Hbcrownwealth?

When you source pole line hardware from Hbcrownwealth, you work directly with a manufacturer and wholesale supplier.

We support:

• Bulk production
• OEM and ODM orders
• Technical drawings and samples
• Multiple pole line bolt types
• Hot-dip galvanized hardware
• Customized packaging
• Export supply
• Mixed product purchasing

If you are buying for a utility project, distribution network, wholesale business, or tender, send us your required dimensions, quantity, drawing, and applicable standard.

We can prepare a suitable quotation according to your project.

Frequently Asked Questions

What is a double upset spool bolt used for?

A double upset spool bolt mounts a spool insulator on the side of a utility pole. Its upset collars create additional clearance between the pole and insulator.

What size double upset spool bolts are available?

Standard Hbcrownwealth models include 5/8″ × 9″, 5/8″ × 10″, and 5/8″ × 12″ shank sizes. Custom sizes are available according to order requirements.

What is the offset of a double upset spool bolt?

The standard double upset design provides approximately 1-5/8″ of offset from the pole.

Are the collars welded to the bolt?

No. The collars are forged rather than welded, creating an integral bolt structure.

What hardware comes with the spool bolt?

The standard assembly includes square nuts, a round washer, a concave square locknut, and a cotter pin.

Are the spool bolts hot-dip galvanized?

Yes. These models use a hot-dip galvanized finish for outdoor corrosion protection.

Can you manufacture spool bolts to our drawing?

Yes. You can provide your drawing, dimensions, sample, technical standard, packaging requirements, and order quantity for OEM or ODM production.