Rawlplug & Wall Anchor Drill Size Chart
Wall plugs · Sleeve anchors (rawlbolts) · Chemical anchors — correct drill bit for every fixing
SDS+ Masonry Drill Bit Set
5–16 mm SDS+ bits for rawlbolts and chemical anchors in concrete and brick.
Wall Plug Assortment Pack
Mixed yellow, red and brown plugs — ideal workshop drawer kit.
Sleeve Anchor / Rawlbolt Set
M8–M16 sleeve anchors for fixing equipment to concrete shed walls.
Chemical Anchor / Resin Kit
Fischer or Hilti-type resin anchor for structural fixings in masonry.
Cordless SDS Hammer Drill
For drilling rawlbolt holes in concrete — makes a huge difference on 14 mm+.
Hole Cleaning Blower / Brush
Chemical anchors need a clean hole — pump blower is essential.
| Plug Colour | Drill (mm) | Screw Size | Max Load | |
|---|---|---|---|---|
Yellow | 5 | 3–4 mm No.5–8 | ≤25 kg | |
Red | 6 | 3.5–4.5 mm No.8–10 | ≤40 kg | |
Brown | 7 | 4.5–5.5 mm No.10–14 | ≤60 kg | |
Blue | 10 | 6–7 mm No.14+ / M6 | ≤100 kg |
Which Fixing Should I Use?
Choosing the right anchor depends on the base material, the load, and how quickly you need to work. Here is a plain-English guide.
Plastic Wall Plugs
Light to medium loads, brick and blockwork
Best for everyday workshop fixings — shelving, equipment mounts, cable management, light brackets. Quick to install and cheap. Drill the correct size, push the plug flush, drive the matching screw. Not suitable for structural or overhead dynamic loads.
Mechanical Anchors (Rawlbolts)
Medium to heavy loads, solid concrete and dense brick
The workhorse of farm building fixings. M10 and M12 rawlbolts are standard for slurry scraper rails, feed barriers, motor bases and roller door tracks. Load immediately after installation. Requires solid substrate — won't work reliably in hollow block or aerated concrete.
Chemical Anchors
High loads, cracked concrete, close edge distances
Required when loads are high, when drilling close to edges, or in cracked concrete. Common for steel column bases, portal frame anchor bolts and agricultural building frame fixings. Higher tensile performance than mechanical anchors but requires hole cleaning and cure time.
Installation Tips for Farm & Workshop Use
Check concrete quality first
Older farm buildings often have weaker concrete than modern specifications. If the concrete is crumbling, powdery or heavily carbonated, use chemical anchors or increase your safety factor — mechanical anchors can pull out of weak concrete.
Always clean chemical anchor holes
Blow the hole with compressed air, brush with a wire brush, blow again. Chemical anchor failures are almost always from dust contamination. A cheap pump blower from the workshop should become part of your standard routine.
Use SDS bits for 14 mm+ holes
A hammer drill with masonry bits works for small holes, but for M10 rawlbolts (14 mm) and larger in concrete, an SDS drill and SDS bits make a dramatic difference to speed, hole quality and accuracy.
Watch out for hollow block
Modern agricultural buildings often use hollow concrete blocks in non-structural areas. Standard rawlbolts won't grip in hollow sections — use a cavity anchor, drill through to solid backing, or use frame fixings rated for hollow masonry.