All sign clips sold by Sign Trade Supplies are compatible with small, medium, medium interlocking, and large aluminium sign channel. This is also true of almost all UK-based aluminium sign channel, regardless of manufacturer.
Our stainless steel sign clips are designed to work with any channel size. This keeps your fixing options as simple as possible — you do not need to match clips to a specific channel type when specifying your post diameter. One clip range covers all four channel profiles.
What are sign clips?
Sign clips — sometimes called sign post clips, channel clips, or post fixing clips — are the hardware components used to attach aluminium sign channel to a sign post. They are an essential part of any post-mounted sign installation, acting as the mechanical link between the sign panel assembly and the upright post.
Without sign clips, aluminium channel cannot be securely fixed to a post. They grip the outside of the channel profile and bolt or clamp around the post, holding the sign in position at the correct height and angle. Most sign clips are designed to allow height adjustment after installation, which is useful on sites where the ground is uneven or where signs may need repositioning in future.
Sign clips are used across a wide range of sign types, including:
- Car park signs and wayfinding signs
- Street nameplates and community notice boards
- Private road and estate signage
- Health and safety signs mounted on posts
- Retail and commercial site directional signage
- School, hospital, and leisure facility signage
They are a standard component in the sign-making industry and are specified on virtually every externally post-mounted aluminium sign panel installation in the UK.
What are sign clips made from?
Sign clips are most commonly manufactured from stainless steel, and this is the material used for all sign clips available from Sign Trade Supplies. Stainless steel is the industry-standard choice for external sign fixings for several reasons:
- Corrosion resistance — stainless steel performs reliably outdoors over long periods without rusting, even in coastal or high-moisture environments
- Strength — stainless steel clips provide a secure, rigid fixing that will not flex or fail under the load of a mounted sign panel
- Low maintenance — once installed, stainless steel fixings require no ongoing treatment or protective coating to maintain their integrity
- Aesthetic finish — stainless steel has a clean, professional appearance where clips are visible on the post
- Longevity — well-specified stainless steel fixings will outlast the sign panels themselves in most installation environments
Some lower-cost sign clips exist in the market made from zinc alloy or plastic, but these are generally not recommended for permanent external installations due to reduced durability. For trade sign makers specifying signage intended to last, stainless steel is the correct choice.
What sizes of aluminium sign channel are there?
Aluminium sign channel is available in four standard sizes used across the UK sign-making industry. These sizes refer to the width of the channel face and determine how thick a sign panel the channel can accommodate.
- Small channel — suitable for smaller sign panels; commonly used on lightweight or smaller format signs
- Medium channel — the most widely used profile; suitable for standard 3mm ACM or 2.5mm solid aluminium sign panels
- Medium interlocking channel — a variant of medium channel with an interlocking edge designed to allow panels to join together without visible gaps; popular on modular and multi-panel sign systems
- Large channel — designed to accommodate much larger sign panels for things like motorway signage and gantry signage
All four channel sizes follow broadly consistent external profile dimensions from UK manufacturers, which is why a single sign clip design can be engineered to work across all four types.
How do sign clips attach to the post?
Sign clips are designed to clamp around a circular hollow section (CHS) aluminium or steel sign post (square clips also available). The clip wraps around the post and is tightened using M8 sqaure head bolts, which compress the clip against the post surface and lock it in position at the required height.
The clip simultaneously engages with the back face of the aluminium sign channel, gripping it securely so the channel — and the sign panel held within it — cannot move independently of the post. Most designs allow the clip to slide up and down the post before tightening, making height setting straightforward on site.
Key points about how sign clips work in practice:
- Clips are specified by post diameter — different clip sizes are available to suit different post diameters
- Installation typically requires only basic hand tools (a spanner or socket set)
- Sign clips allow fine height adjustment during installation before final tightening
- Sign clips can be loosened and repositioned if a sign needs to be moved after installation
- For two-post installations (where a sign panel is fixed between two uprights), clips are fitted symmetrically on each post at matching heights
Which sign clips are compatible with which channel?
All sign clips available from Sign Trade Supplies are compatible with small, medium, medium interlocking, and large aluminium sign channel. You do not need to select a different clip depending on which channel size you are using.
This universal compatibility applies to almost all aluminium sign channel manufactured and sold in the UK, not just channel supplied by Sign Trade Supplies. The external profile dimensions of UK aluminium sign channel are broadly consistent across manufacturers, meaning that clips engineered to this standard will work regardless of which supplier the channel was sourced from.
The only scenario where compatibility should be verified is when using non-standard, imported, or proprietary sign channel systems that may deviate from typical UK profile dimensions.
Do I need to specify different clips for different post diameters?
Yes — sign clips are sized by the diameter of the post they are designed to fit, not by the channel size. When selecting sign clips, you need to match the clip to your post diameter. Common post diameters used in UK signage include 42mm, 48mm, 60mm, 76mm, and 89mm CHS, though other sizes are available.
Importantly, while you do need to select the correct clip for your post diameter, you do not need to select a different clip for different channel sizes. The same clip that fits a given post diameter will work with small, medium, medium interlocking, and large channel alike. This means your clip selection process is straightforward: choose the clip that matches your post, and it will be compatible with whichever channel profile your panels are using.
Can sign clips be used on both aluminium and steel posts?
Yes. Sign clips grip around the outside of the post and are not dependent on the post material. Stainless steel sign clips will fix securely to both aluminium CHS posts and galvanised or mild steel CHS posts of the same diameter. The fixing method is the same in both cases.
When combining stainless steel clips with galvanised steel posts in coastal or highly corrosive environments, it is worth considering whether any bimetallic contact between dissimilar metals could accelerate corrosion over very long timescales. In most standard commercial signage applications this is not a significant concern, but it is a factor worth noting on projects where fixings will be in place for 10 years or more in aggressive environments.
How many sign clips do I need per sign?
The number of sign clips required depends on the size and weight of the sign panel and the number of posts being used. As a general guide:
- Single-post signs — typically two clips per post (one at the top of the channel, one at the bottom), giving four clips per sign for a standard panel with top and bottom channel
- Two-post signs — typically two clips per post position, giving four clips in total for a standard two-post installation
- Larger or heavier panels — additional clips may be specified at intermediate points along the channel to reduce flex and provide additional support
For most standard sign installations, a pack of four sign clips will cover a single sign on a single post. For two-post installations or larger format signs, quantities should be calculated per post based on the number of fixing points required.
Browse sign clips and accessories
You can view the full range of sign post clips and fixing accessories available from Sign Trade Supplies here: Sign Post Clips & Accessories — Sign Trade Supplies
If you are unsure which clip is right for your post diameter, panel size, or project specification, contact our team and we will be happy to advise.
Quick reference summary
- All STS sign clips are compatible with small, medium, medium interlocking, and large aluminium sign channel
- Compatible with almost all UK-manufactured aluminium sign channel regardless of supplier
- Stainless steel construction — corrosion resistant and suitable for permanent external installation
- Clips are sized by post diameter, not channel size — select the clip that matches your post
- Works on both aluminium and steel CHS posts
- Typically four clips are needed per single-post sign installation
- Height-adjustable during installation on most clip designs