Stair tread bolt Set 21A for 6–9 mm thick steel stringers

Stair tread bolt Set 21A – concealed tread fixing to steel stringers

LamiFIX Set 21A connects grooved wooden treads to 6–9 mm thick steel stringers. The connection is discreet and almost invisible in the groove. Each tread can be removed individually.

Design and installation

The fixing passes through a Ø16 mm hole in the steel stringer. The round nut and spacer sleeve are made of INOX A2 stainless steel. The spacer sleeve has a diameter of Ø25 mm and creates an 18 mm gap to the tread. The round nut head has a diameter of Ø30 mm.

The M10 thread of LamiFIX connector LF 35.M10x30 is shortened to 16.5 mm for Set 21. The spacer sleeve and round nut clamp the steel stringer firmly and precisely. Secure the thread with threadlocker. Slide the grooved wooden tread into place and screw it from below. Version A is suitable for straight stairs or in combination with a tread suspension system.

Light appearance, straightforward manufacture

The steel stringer can arrive for installation fully laser-cut and powder-coated. Welded brackets are no longer needed. This shortens production time and makes installation and transport easier. The gap between the wooden tread and steel stringer gives the treads a floating appearance.

Required quantity per Set

• 1 LamiFIX M10 connector, LF 35.M10x30 (catalogue LF 1035.130)
• 1 raised countersunk screw 5.5 × 32 mm, LF 1541.002.1
• 1 cut to shorten the M10 thread on the LamiFIX connector to 16.5 mm
• 1 spacer sleeve Ø25 × 18 mm, INOX A2, LF 3624.018
• 1 round nut M10, INOX A2, LF 3813.030.1
• 1/100 threadlocker LF 3806.243.1

The component list shows the quantities required per Set. Screws are supplied in whole packs and threadlocker in whole tubes. Final quantities depend on the number of Sets.

Article number: LF 3614.121.4
For 100 Sets or more: LF 3614.121.6
For steel stringers 6–9 mm thick. Set 22 is intended for stringers 9–12 mm thick.