Anchor Spikes/Ford Axle/Bull Prick

An anchor spike is a heavy-duty, solid metal rod. Grips on a film set know this tool by several different names. These include the Ford Axle or the crude but common term, Bull Prick. Its function is simple but critical. It creates a temporary, secure anchor point in the ground. Grips use this to tie down large or heavy equipment, especially on outdoor locations.

The Core Purpose: Safety First

Safety is the primary reason for using an anchor spike. On location, wind is a grip’s biggest enemy. A sudden gust of wind can catch large pieces of equipment. It can turn an overhead butterfly frame into a dangerous sail. It can also topple scaffolding towers or large lights on high stands.

An anchor spike provides a fixed, reliable point to secure this gear. A grip drives the spike into the earth. They then use ratchet straps or high-tensile rope to tie the equipment off to the spike. This action prevents the equipment from moving, tipping over, or flying away. This secures the set and protects the cast, crew, and expensive gear.

How Grips Use an Anchor Spike

Using an anchor spike is a straightforward process. First, a grip identifies a suitable patch of ground. This must be soft earth, grass, or packed sand. The spike will not work on concrete, asphalt, or rock.

Next, the grip uses a sledgehammer. They drive the heavy spike deep into the ground. The spike must go deep enough to guarantee a secure hold that can resist immense pulling force.

Once the spike is set, the grip attaches the tie-down lines. They run these lines from the spike to the equipment. They then tension the lines to ensure the equipment is stable. For very large setups, like a 20×20 overhead frame, the crew will use multiple anchor spikes. This creates a secure perimeter.

Common Applications

Grips use anchor spikes to secure a variety of large items, including:

Overhead Frames	Any large butterfly or overhead frame (like a 12×12 or 20×20) needs to be tied down in the wind.
Scaffolding	Towers built for lights or cameras must be anchored to prevent swaying or toppling.
Large Tents	Production tents, catering tents, or “circus” tents must be secured.
Truss Rigs	Ground-supported lighting or audio truss requires anchoring, especially for outdoor events.
Camera Cranes	The base of a large jib or camera crane may be secured for extra stability.

Understanding the Names

The tool’s various names are very descriptive.

Anchor Spike	This is the most formal and descriptive term. It clearly states the tool’s function.
Ford Axle	This name comes from the tool’s appearance. It is a thick, heavy, solid piece of metal, much like a drive axle from an old Ford vehicle. In fact, many early grip spikes were repurposed car axles.
Bull Prick	This is a traditional, crude grip term. It is a vulgar but vivid description of a large metal spike being driven into the earth.

Regardless of the name, this simple piece of steel is a fundamental tool. It is essential for on-set safety.

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