What is a spanhuls (slotted drive sleeve)?
A spanhuls, also called a hulsnagel in Dutch, is a cylindrical steel sleeve slotted along its length and fitted with a collar, which is driven into a drilled hole with a hammer. It works like a kind of hammer-in plug: the drilled hole is slightly smaller than the diameter of the sleeve, so the sleeve is compressed as it is driven in and, thanks to its spring action, grips the wall of the hole. The collar holds the material being fixed. The tip is slightly tapered, so the sleeve is easy to start in the hole.
Application
Slotted drive sleeves are used to fix timber battens, laths, rails and clips quickly and firmly to concrete, masonry or stone. They are often made of hardened spring steel and are available in various diameters and lengths.
Step by step:
- Choose the size. The length is the thickness of the material being fixed plus the required embedment depth in the substrate. Follow the manufacturer’s specification for drill diameter and minimum anchorage depth.
- Drill through the timber. Position the batten and drill through timber and substrate in one go (push-through installation). This keeps the holes in line.
- Clean the hole. Blow or vacuum out the drilling dust; dust reduces the clamping force.
- Drive it in. Drive the sleeve in straight until the collar sits tight on the timber. The best result is achieved when the sleeve grips over the full length of the hole.
Note:
- Slotted drive sleeves are intended for light to medium-duty fixings. For heavy or safety-critical loads (balustrades, brackets), choose an approved anchor as specified by the manufacturer.
- In soft or hollow substrates (aerated concrete, hollow blocks) a drive sleeve grips poorly. Use a plug designed for that substrate instead.
- A drive sleeve is difficult to remove, so decide on its position carefully beforehand.
Common mistake: drilling a hole that is too large, for example with a worn or wrong bit. The sleeve can then no longer spring open and sits loose.
Related terms
- Hammer-in plug
- Hollow wall anchor
- Nail
- Batten
- Concrete
- Wedge anchor
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