RAPID SuperSenkFix Screws for Timber and CLT

Schmid RAPID® SuperSenkFix screws are partial-thread structural timber screws developed for strong, tightly drawn connections with a clean flush head finish. Their applications include timber framing, cross-laminated timber and suitable steel-to-timber connections.

What is a SuperSenkFix screw?

The range combines a structural partial thread with Schmid’s SuperSenkFix head. The head geometry is intended to deliver high pull-through values while seating flush in the timber. This makes it relevant where the connection depends on head-side restraint but a projecting washer head is unsuitable.

The shoulder below the head provides controlled centring in suitable steel bores, allowing the range to be considered for specified metal-to-timber details as well as timber-to-timber work.

Typical structural timber applications

Rafter and timber-frame connections
Timber strengthening and doubling work
Wall, floor and corner connections in CLT construction
Angled and cross-grain screw arrangements
Suitable steel plates or formed metal components fixed to timber

Using SuperSenkFix screws in CLT

CLT connections can involve face fixing, narrow-edge fixing, end-grain conditions and angled screws. These details place different demands on thread withdrawal, head pull-through, shear resistance, spacing and installation accuracy.

Schmid identifies RAPID® SuperSenkFix for CLT wall and ceiling connections, including side faces and narrow edges. This product suitability does not remove the need for an engineered connection design. The designer must determine the screw diameter, length, number, angle, edge distances and spacing.

Feature	Typical Uses
Partial thread	Draws the head-side component towards the receiving timber when the thread is fully engaged in the lower member.
SuperSenkFix head	Provides a flush finish with high resistance to the head pulling through the timber.
Self-drilling tip	Provides a quick, accurate start and helps limit splitting under the approved installation conditions.
Low-resistance shank and thread	Reduces driving effort on long structural fixings.
Under-head shoulder	Helps centre the fixing in compatible steel bores.

Partial-thread installation principle

For a partial-thread screw to clamp two timber components correctly, the thread should be fully within the receiving component. If part of the thread remains in both members, the connection may not pull together as intended.

Confirm the specified screw size, angle and position.
Clamp or hold the components in their final alignment.
Use the correct drive bit and keep the driver aligned with the screw.
Drive until the head is flush; do not bury it unnecessarily.
Check the completed connection against the specified layout.

Pre-drilling: Schmid describes the patented tip as self-drilling and suitable for installation without pre-drilling in its approved applications. Timber species, density, moisture, edge distance and project requirements can still make a pilot hole necessary.

Finish and exposure

The stocked product finish should be checked against the service environment. A plated structural screw should not automatically be treated as suitable for every external, coastal, chemically treated or permanently damp application. Confirm the product specification and required corrosion resistance before installation.