Which CAS Clamp Do I Need?

Written By Con Dun

Choosing the right clamp shouldn't slow you down on set. The Cat O' Nine CAS range covers every common tube size in film and TV rigging, and because the whole range is interchangeable, you can mix sizes on a single rig. Here's how to pick the right one — fast.

The short answer

Match the clamp to the tube you're rigging:

Need to join two different sizes? Use a step clamp — 16→19, 16→32 or 16→48 — covered further down.

What is a CAS clamp?

A CAS clamp is a two-part split clamp that joins or rigs tube securely, with a fast lock and release for on-set adjustments. Every clamp in the range comes hard anodised in black and is machined from 6082-T6 aluminium — a high-strength structural alloy that stays light without giving up rigidity. Each clamp ships with an M8 locking bolt (6mm hex head).

The key feature: every CAS clamp is interchangeable with every other size. A 19mm clamp connects directly to a 32mm clamp, so you can rig 19mm and 32mm tube on the same mount without adapters.

Which size for which job?

16mm CAS Clamp

The lightest in the range. Use it for compact rigging where you don't need to carry serious load — small accessory arms, lightweight mounts, tight builds where a low profile matters. Comes with the M8 locking bolt.

19mm CAS Clamp

The camera department's workhorse. 19mm is the standard for heavy-duty camera rods, so this is the clamp for locking a camera into a rig. Use it any time you're rigging 19mm tube or running 19mm rod.

25mm (1") CAS Clamp

The in-between size. Useful when you're working with 1-inch tube that the 19mm and 32mm clamps won't fit. A common requirement on mixed rigs and older kit.

32mm CAS Clamp

The car-rig and lock-off clamp. 32mm tube is the backbone of vehicle rigging, suction-mount builds and heavier lock-offs, and this is the clamp that holds it. It carries two extra 3/8" threaded holes for additional mounting points — handy for hanging accessories straight off the clamp. The go-to for anything that needs to take abuse.

48mm CAS Clamp

The heavy hitter. Sized to take 48.3mm scaff tube, so it bridges the gap between film rigging and scaffolding — ideal for large camera grids, lighting structures and structural builds. Also carries two 3/8" threaded holes for mounting.

I need to join two different tube sizes — what do I use?

That's what the step clamps are for. Instead of forcing a workaround, a step clamp takes a different tube on each side:

  • 16mm to 19mm — step a 16mm build up to 19mm rod or tube

  • 16mm to 32mm — connect lightweight 16mm tube to a 32mm car-rig spine

  • 16mm to 48mm — tie 16mm tube into a 48mm or scaff structure

Because the whole range is interchangeable, you can also chain standard clamps together to bridge sizes — but a step clamp is the cleaner, faster solution when you know you'll be mixing sizes regularly.

Do CAS clamps fit standard industry kit?

Yes. The range is designed from the ground up to integrate with standard film and TV rigging — 19mm camera rods, scaff tube, and common tube diameters across departments. If you've got a specific compatibility question, just ask before you order.

What's the load rating?

Every CAS clamp is machined from solid 6082-T6 aluminium and hard anodised for strength and corrosion resistance, giving a rigid, high-tolerance hold. For specific load figures on a particular rig, get in touch — we're grips ourselves and would rather talk it through than have you guess.

Are they in stock?

Most sizes are held in stock and dispatched fast from the UK — no waiting weeks for parts to come back into supply. Stock levels are shown live on each product page. Made-to-order items carry a 6–14 day lead time.

Still not sure?

We're working grips and camera assistants, not a call centre. If you tell us what you're rigging, we'll tell you exactly what you need. Email info@catonineengineering.co.uk or call 0161 526 0391.

Shop the full CAS range →‍ ‍The CAS Range

Con Dun
Next

Everything You Need to Know About Cat O' Nine Engineering