Selectron 7.5x200 Buldex Screw (50 Pieces)

Selectron 7.5×200 Buldex Screw — 50 Pieces

The Selectron 7.5×200 mm Buldex Screw is an extra‑long, purpose‑built fastener designed for direct installation without wall plugs into solid structural surfaces such as concrete, aerated concrete, brick, and natural stone. Its effective 200 mm length delivers a superior solution for thick wall cladding, heavy‑duty assemblies requiring deep anchoring, and securing multi‑layered building components together. It forms its own thread within the pilot hole to create a monolithic bond with the base material — eliminating both plug cost and extended installation time. With a T30 Torx drive and zinc‑coated robust body, it ensures reliable performance in high‑load projects. The 50‑piece box provides the ideal supply quantity for large‑scale construction, residential, and commercial build programmes.

Technical Specifications

• Brand: Selectron
• Type: Buldex Screw / Plug‑Free Masonry Fastener
• Diameter: 7.5 mm
• Overall Length: 200 mm
• Head Style: Countersunk — T30 Torx (Star)
• Point Style: Sharp Point
• Thread Profile: Special Sharp Design — self‑tapping with integrated debris‑clearance channels to prevent jamming
• Material: Hardened and Tempered High‑Carbon Steel
• Coating: Electro‑Galvanised Zinc — corrosion resistant
• Recommended Pilot Hole: Concrete/Solid Brick: 6 mm | Aerated Concrete: 5 mm
• Compatible Substrates: Concrete, Aerated Concrete, Solid Brick, Hollow Brick, Natural Stone, Multi‑Leaf Walls
• Compatible Fixtures: Thick PVC/Aluminium Frames, Timber Beams, Steel Sections, Facade Panels
• Packaging: 50 Pieces per Box

Applications

• Deep anchoring of thick‑profile PVC and aluminium window and door systems
• Fixing timber beams, large frames, and structural components to concrete foundations
• Securing exterior cladding, curtain‑wall panels, and thermal insulation systems
• Connecting outer finishes to the main load‑bearing wall in multi‑layer constructions
• Mounting heavy shelving, machine bases, air‑conditioning units, and load‑bearing brackets
• High‑capacity fixing in aerated concrete and lightweight concrete walls
• Prefabricated building, steel‑frame, and large‑scale renovation projects
• Deep‑embedment connections through thick wall and ceiling assemblies

Product Advantages

• Plug‑Free Installation: No separate wall plug required — lowers material cost and shortens labour duration
• 200 mm Extra‑Long Length: Ideal for deep embedment through thick sections, cladding layers, and stacked assemblies; one screw secures multiple strata in a single pass
• Self‑Tapping Thread: Forms its own thread in the prepared hole; debris channels prevent binding, ensure full seating, and resist long‑term loosening
• T30 Torx Drive: Positive bit engagement eliminates slippage and cam‑out; delivers consistent torque transfer even with extra‑long fasteners
• Zinc Coating: Long‑term corrosion resistance for indoor and sheltered outdoor environments
• Hardened Steel: Resists bending and breaking despite its extended length; provides deep, consistent clamping force
• Removable and Reusable: Not a permanent, irreversible anchor — can be extracted and re‑installed as required
• 50‑Piece Box: Reliable supply for large projects; practical stockholding for low‑volume but long‑length fastener requirements

Installation Guidelines

• Drill a 6 mm pilot hole in concrete or solid brick; use 5 mm for aerated concrete; make the hole approx. 10–15 mm deeper than the screw’s intended embedment
• Completely clear dust from the bore using a brush and compressed air — residual debris significantly reduces holding power in long‑length fixings
• Drive the screw at a true right angle to the surface; the extended shank is more sensitive to angled insertion, which weakens thread engagement and may cause breakage
• Use a T30 Torx driver bit with a low‑speed, high‑torque screwdriver; excessive speed overheats the tip and reduces performance
• Apply moderate torque and slow rotation in hollow brick or lightweight masonry; internal webs may fracture under excessive force
• Select stainless steel versions for permanent outdoor exposure, persistent humidity, or coastal environments
• For high‑load‑critical applications, determine fastener count, spacing, and embedment depth based on structural calculations
• Store in dry conditions; prolonged moisture exposure shortens coating life

Frequently Asked Questions

How much of the 200 mm length actually provides holding power?
While it varies with substrate, typically 120–150 mm penetrates the base material to form a secure anchor — passing fully through thick cladding layers to reach the structural wall behind.

Does it hold firmly without a wall plug?
Yes — the custom thread profile cuts its own robust bond within the pilot hole; no separate plug is needed.

How does it differ from shorter lengths?
The 60 mm and 80 mm models are designed for shallow connections; the 200 mm variant is purpose‑engineered for thick assemblies, multi‑leaf walls, and heavy‑duty anchoring.

Will it rust?
Zinc electro‑plating is sufficient for indoor and sheltered outdoor use; the stainless steel version is recommended for permanent water exposure.

How many should I use?
For heavy‑duty fixings: a minimum of two at each corner, spaced 250–300 mm along intermediate runs; increase quantity in line with applied load.