No-Drive Binding Posts (Chicago Screws)

Description

Binding Post and Screw Sizes, Lengths & Specifications

The tables below list standard #8-32 binding posts and matching screws, including smooth-head no-drive post lengths, post body and head dimensions, and available slotted screw lengths. Select the required post and screw combination for your RFQ. Additional thread sizes, lengths, materials, finishes and drive styles may also be available for OEM production.

What Is a No-Drive Binding Post?

A no-drive binding post is the internally threaded female component of a two-piece binding post and screw assembly. Its head has a smooth surface without a slot, Phillips recess, hex socket or other tool-engagement feature.

The female post passes through the materials being joined, while a matching male screw threads into the post from the opposite side. Once assembled, the smooth post head provides a clean appearance and cannot be turned with a conventional screwdriver from that side.

No-drive binding posts are also commonly called:

• Smooth head binding posts
• Unslotted binding posts
• No-slot binding posts
• Smooth head Chicago screw posts
• No-drive barrel nuts
• Unslotted barrel nuts
• Tamper-resistant binding posts
• Female sex bolts
• Binder posts

These names describe the female component. A matching male screw is required to complete the assembly.

Why Use a No-Drive Head?

A no-drive head offers two primary advantages:

• It provides a smooth, uninterrupted visible surface.
• It limits tool access from the female-post side of the assembly.

This makes no-drive posts useful for decorative panels, furniture, architectural hardware and public-facing installations where a visible drive recess is undesirable.

No-drive binding posts provide tamper resistance, but they are not automatically tamper-proof. If the matching male screw remains accessible and uses a standard drive, the assembly can still be removed from the screw side.

For greater security, no-drive posts may be paired with one-way, pin Torx or other security-drive screws.

Standard #8-32 Post Lengths

Standard #8-32 smooth head binding posts are available in the following listed lengths:

• #8-32 × 1/4″ No-Drive Binding Post
• #8-32 × 5/16″ No-Drive Binding Post
• #8-32 × 3/8″ No-Drive Binding Post
• #8-32 × 1/2″ No-Drive Binding Post
• #8-32 × 5/8″ No-Drive Binding Post
• #8-32 × 3/4″ No-Drive Binding Post
• #8-32 × 1″ No-Drive Binding Post
• #8-32 × 1-1/4″ No-Drive Binding Post
• #8-32 × 1-1/2″ No-Drive Binding Post
• #8-32 × 1-3/4″ No-Drive Binding Post
• #8-32 × 2″ No-Drive Binding Post
• #8-32 × 2-1/4″ No-Drive Binding Post
• #8-32 × 2-1/2″ No-Drive Binding Post
• #8-32 × 2-3/4″ No-Drive Binding Post
• #8-32 × 3″ No-Drive Binding Post
• #8-32 × 3-1/4″ No-Drive Binding Post
• #8-32 × 3-1/2″ No-Drive Binding Post
• #8-32 × 3-3/4″ No-Drive Binding Post
• #8-32 × 4″ No-Drive Binding Post

Standard #8-32 post dimensions:

• Body Diameter: 0.203″
• Head Diameter: 0.420″
• Head Height: 0.031″

Additional thread sizes and special dimensions may be available depending on the required material, finish and quantity.

Matching Screws

No-drive binding posts are used with a matching male screw of the same thread size.

Common #8-32 slotted screw lengths include:

• #8-32 × 3/16″ Slotted Screw
• #8-32 × 1/4″ Slotted Screw
• #8-32 × 5/16″ Slotted Screw
• #8-32 × 3/8″ Slotted Screw

Other screw lengths and drive styles may be available, including:

• Phillips
• Phillips/Slotted Combination
• Six-Lobe
• Six-Lobe with Security Pin
• One-Way Security Drive
• Custom Drive Configurations

The correct screw length depends on the post length, total material thickness and required thread engagement.

Materials & Finishes

No-drive binding posts and matching screws are available in several materials and finishes:

• Aluminum: Lightweight and corrosion resistant
• Brass-Plated Aluminum: Lightweight with a decorative brass appearance
• Zinc-Plated Steel: Strong and economical for general industrial use
• Chrome-Plated Steel: Provides a bright decorative finish
• Brass: Offers corrosion resistance, conductivity and decorative appearance
• Stainless Steel: Provides strength and increased corrosion resistance

Clear zinc, black zinc, chrome, brass and other application-specific finishes may be available.

Material and finish availability varies by thread size, post length, matching screw and production quantity.

No-Drive vs. Slotted Binding Posts

A no-drive binding post has a smooth female head with no tool-engagement feature. It provides a cleaner visible surface and increased resistance to removal from the post side.

A slotted binding post has a screwdriver slot in the female head. The slot makes it easier to hold the post during assembly or removal but remains visible after installation.

Choose a no-drive post when:

• A smooth visible surface is preferred.
• The female side is publicly accessible.
• Increased tamper resistance is required.
• A visible drive slot is undesirable.
• The male screw side remains accessible for installation.

Choose a slotted post when convenient installation and removal from both sides are more important.

How to Select the Correct Size

When selecting a no-drive binding post assembly, consider:

• Total material thickness
• Female post length
• Internal thread size
• Matching screw length
• Required thread engagement
• Post body diameter
• Assembly-hole diameter
• Head diameter
• Material and finish
• Required level of tamper resistance
• Production quantity

The post should pass through the assembled materials without excessive looseness. The matching screw must engage sufficient internal thread without creating unwanted projection or bottoming out.

When requesting a quote, provide the thread size, post length, screw length, material, finish and quantity.

Assembly

No-drive binding posts are assembled from two sides:

1. Prepare an assembly hole that fits the post body.
2. Insert the smooth-head female post through the material.
3. Insert the matching male screw from the opposite side.
4. Thread the screw into the post.
5. Tighten from the screw side until the materials are securely clamped.

Because the female head has no drive, it cannot be held with a standard screwdriver. Proper hole fit, clamping pressure or an anti-rotation body feature may be required depending on the application.

Typical Applications

No-drive binding posts are commonly used in:

• Architectural panels
• Commercial restroom hardware
• Public-facing fixtures
• Furniture and cabinetry
• Decorative panels
• Retail displays and signage
• Leather goods
• Sample books and presentation materials
• Equipment panels
• Door and kickplate hardware
• Multi-layer assemblies
• Security-conscious installations
• General OEM products

Factory-Direct Supply & Custom Options

Imperial Rivets & Fasteners supplies factory-direct no-drive binding posts, smooth head Chicago screw posts and matching male screws for distributors, manufacturers and OEM production.

Available options may include:

• Standard #8-32 lengths from 1/4″ through 4″
• Additional inch thread sizes
• Custom post and screw lengths
• Aluminum, steel, brass and stainless steel
• Decorative and corrosion-resistant finishes
• Slotted and security-drive matching screws
• Parts manufactured to drawings or samples
• Matching post-and-screw sets
• Production-volume packaging

Select a standard post length from the specification table and add it to your RFQ. If the required thread, length, material or matching screw is not listed, send our sales team your drawing or application requirements for review.

Questions or Custom Requirements?

Contact our sales team at sales@imperialrivet.com or (630) 964-0208.