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Threaded Inserts · Trade series (compression limiters) · Application guide

What Are Unthreaded Compression Limiters Used For?

Typical applications, the industries that specify unthreaded compression limiters, and how to choose the right size, material and finish for the joint.

Unthreaded Compression Limiters are used for limiting clamping compression through a soft or composite assembly with an unthreaded sleeve. They are manufactured to Trade series (compression limiters), and selection is driven by the size designation, the fit and tolerance the assembly requires, and the service environment.

Primary duty
Limiting clamping compression through a soft or composite assembly with an unthreaded sleeve
Governing standard
Trade series (compression limiters)
Size designation range
CL220 / CL200 to CL500 / CL6000 / CL6100 / CL8000 / CL8100 / CL620
Category
Threaded Inserts

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are Unthreaded Compression Limiters Used For? application image

The primary duty of Unthreaded Compression Limiters is limiting clamping compression through a soft or composite assembly with an unthreaded sleeve. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly 220 to 500, they cover heavy and structural work.

Typical Applications for Unthreaded Compression Limiters

The most common settings where these are specified:

  • Plastic housings: Compression limiters stop a bolt from crushing a molded boss.
  • Automotive assemblies: Steel, aluminum or brass sleeves maintain the designed clamp gap.
  • Composite panels: Molded-in forms spread bolt load through a non-metal part.
  • Machine covers: Press-in limiters protect a soft housing during repeated tightening.

How to Specify Unthreaded Compression Limiters for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans 220–500; check the full table below for the exact dimensions of each size.
  • Tap & length: Drill and tap to the specified STI size, and pick insert length (commonly 1.5×D or 2×D) for the load and parent material strength.
  • Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
  • Standard: This product is supplied to Trade series (compression limiters). Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

  • Drill and tap with the specified STI tap — a standard tap will not produce the correct thread for the insert.
  • Install to the specified depth (typically 0.25–0.5 mm below the surface) and remove the tang where the design requires it.

Common Selection Mistakes with Unthreaded Compression Limiters

  • Fitting an insert into strong steel that already holds a thread — added cost for no gain.
  • Skipping the tang removal, which then blocks the mating screw.

Where Unthreaded Compression Limiters Are Not the Right Choice

Not a fix for a hole that is already oversized beyond the STI tap range, and not needed in steel that already holds a thread well.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (Trade series (compression limiters))

Design familyBolt rangeParent bolt class exampleMaterial optionsInstallationCompression reference
CL220 / CL200M3~M12 and #4~3/88.8 / SAE Grade 5steel / 2024 aluminum / C36000 brasspress-in or molded-inrated at 2.5% compression
CL350M3~M12 and #4~3/810.9steel / 2024 aluminum / C36000 brasspress-in or molded-inrated at 2.5% compression
CL400 / CL460M3~M12 and #4~3/88.8steel / 2024 aluminum / C36000 brasspress-in or molded-inrated at 2.5% compression
CL500 / CL6000 / CL6100 / CL8000 / CL8100 / CL620M3~M12 and #4~3/88.8 / 10.9 / Grade 5 / Grade 8steel / 2024 aluminum / C36000 brasspress-in or molded-inrated at 2.5% compression
Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

How do I choose the right size of Unthreaded Compression Limiters?

Match the nominal size to the mating thread or hole. This product is available from 220 to 500; the full dimension table on this page lists each size.

When should I use Unthreaded Compression Limiters instead of tapping directly?

Use them in soft alloys, plastics or thin sections where a cut thread would strip, or to repair a stripped hole. In strong steel that already holds a thread well, they are usually unnecessary.

What material should Unthreaded Compression Limiters be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Unthreaded Compression Limiters made to a recognized standard?

Yes — they are manufactured to Trade series (compression limiters), so dimensions are interchangeable between suppliers when you quote the standard on your order.

Can I get a quote for Unthreaded Compression Limiters in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.