Strut Beam Clamp Selection Guide
A beam clamp grips the flange of a steel beam to give you an attachment point for threaded rod, strut, or pipe — with no drilling and no welding. This guide covers the main beam clamp types and how to pick the right one for your beam, your load, and your environment. Everything we stock fits standard strut and rod systems and cross-references to Unistrut, B-Line, PowerStrut, and SuperStrut.
Beam Clamp Types
| Type | Best For | Notes |
|---|---|---|
| Universal / Wide-Throat Malleable | Threaded rod drops from a flange | Malleable iron, the everyday rod hanger; wide-throat fits thicker flanges |
| I-Beam Clamp (light / med / heavy) | Rod or strut from flanges up to 7/8" | Pick duty to suit load |
| Steel / Malleable C-Clamp | Quick rod attachment with locknut | Cup-point set screw; malleable for higher strength |
| Window / Top-Beam Clamp | Top of a flange or purlin | Reaches where a jaw clamp cannot |
| U-Bolt Beam Clamp | Securing strut across a beam | Wraps the flange with a U-bolt |
Three Steps to Choose
- What are you hanging? Threaded rod → universal malleable or I-beam clamp. Strut across the beam → U-bolt beam clamp. A quick single rod → C-clamp.
- How thick is the flange? Standard clamps cover flanges up to 7/8". For thicker flanges use a wide-throat malleable or a heavy-duty clamp rated 7/8"-2".
- What is the load? Match rod size and duty rating. Light/medium for utility hangs; heavy duty and malleable iron for higher loads and larger rod.
Rod-Hanging I-Beam Clamp Sizes (to 7/8" flange)
| Rod Size | Duty | Eugene Fastener SKU |
|---|---|---|
| 1/4" | Medium | STR4815 |
| 3/8" | Medium / Heavy | STR4816 / STR4817 |
| 1/2" | Medium / Heavy | STR4818 / STR4819 |
| 5/8" | Medium / Heavy | STR4820 / STR4821 |
| 3/4" | Heavy | STR48213 |
Universal malleable rod-hanger clamps: STR5103 (3/8), STR5104 (1/2). Also stocked: universal beam clamp STR4804 and window clamp STR4810.
Malleable vs Steel
Malleable iron clamps are cast and carry higher loads — choose them for medium and heavy-duty rod hanging and larger rod. Formed steel clamps suit lighter loads. For wet or coastal sites, ask about stainless. See the finishes guide.
Brand Cross-Reference
| EFS SKU | Description | Unistrut | PowerStrut | B-Line |
|---|---|---|---|---|
| STR5103 | 3/8 universal malleable beam clamp | P2898-37 | PS 93 3/8 | B3034-3/8 |
| STR4804 | Universal beam clamp | P1386 | PS 686 | B355 |
| STR4815 | 1/4 medium I-beam clamp | P1648S | PS 858 1/4 | B303 |
Full chart: Strut Brand Cross-Reference.
Frequently Asked Questions
How do I choose a beam clamp?
Decide what you are hanging (rod, strut, or pipe), measure the beam flange thickness the clamp must grip, and size to the load. For rod hanging, match the clamp rod size to your threaded rod and pick a duty rating. Confirm the clamp flange capacity covers your flange; standard clamps handle up to 7/8 inch, wide-throat and heavy-duty handle thicker.
Do beam clamps need drilling or welding?
No. The jaws grip the existing flange and a set screw or bolt locks the clamp, so the steel is never drilled or welded. This keeps the structural member intact and makes installation fast and reversible.
What is the difference between malleable and steel beam clamps?
Malleable iron clamps are cast and carry higher loads, used for medium and heavy-duty hanging and larger rod. Formed steel clamps work for lighter loads. For higher loads choose malleable.
What size beam clamp for a 1/2 inch threaded rod?
Use a clamp rated for 1/2 inch rod, such as STR4818 (medium duty) or STR4819 (heavy duty) for flanges up to 7/8 inch, or a 1/2 inch universal malleable clamp like STR5104. Match the duty rating to your load.
Related Guides
- Strut Channel Accessories Guide
- How Much Weight Can Strut Hold
- Strut Brand Cross-Reference
- Shop Strut Beam Clamps