Star Knobs

Star knobs are versatile products that deliver high torque applications in a range of industries, including aeronautical, industrial and domestic. Designed to allow for a precise grip, the smooth edges and choice of designs improve efficiency and offer excellent clamping performance.

At Cromwell, our range of star knobs include a choice of lobe designs and are available in male and female options, including female blind and female through designs from dependable suppliers like Ganter®.

What are star knobs?

Used as fixings to grip and temporarily hold items in place, star knobs are a type of clamping knob that feature an ergonomic star shaped handle to allow for an easy grip when loosening or tightening. The shaped handle is sometimes attached to a threaded stud and can feature a varied number of lobes to allow for different levels of control and pressure to be applied when tightening.

Star knobs are often referred to as scallop knobs or hand knobs and are used in a similar fashion to knurled nuts. They're designed for manual use and can sometimes feature a retaining chain or loss prevention chain to prevent their loss when unscrewed.

Star knob types

Star knobs can be made in a wide range of materials, including cast iron, aluminium and plastic. Regardless of material, these products generally follow the same design with smooth, rounded edges for easy grip and torque application.

• Three lobe star knob - Sometimes called a tri-star knob, this type allows for precision grip when tightening.

• Through bore - This type features a threaded or plain hole through the top of the knob

• Blind bore - A female insert with a threaded or plain bore.

• With movable thrust pad - A pad at the end of the stud intended to prevent scratches or denting when tightened.

• With loss protection - Attaches to the neck of the knob with a ring for attaching to a wall

• Safety star knob - Has a locking feature incorporated into one of the spokes to lock in place

Considerations when choosing star knobs

• Female / male - this depends on whether you already have the stud or require the entire component.

• Thread pitch - choose between C (coarse) or F (fine) depending on the application and level of torque required.

• Stud - Ensure your chosen knob either has the correct length and diameter stud for the application, or that the female component will fit onto the chosen stud dimensions.

• Blind / through - for applications where you'll only be manually adjusting the clamping torque, a blind star knob is ideal. However, the through style allows flexibility as to which fastener you use for a job.

• Accessories - this can be a non-marring shoulder or thrust pad to prevent marking softer woods or metals, or loss prevention in the form of a chain or clip.


How does a clamping knob work?

A clamping knob like a star knob is available as either a male component, where the threaded pin is already attached, or a female component, where the handle of the knob must be screwed onto a pre-existing pin. Once attached and inserted, this fastener will provide a high-level of torque to allow the knob handle to anchor into or clamp against an item.