VMAX Tek Screw With XGRiP

vmaX roofing screws: steel or timber with one screw

vmaX is Hobson's DRiLLX roofing screw with a universal drilling point. Hobson says it suits fastening roof sheeting to thin metal battens, timber trusses and steel purlins up to 1.9mm thick, and lists it for crest fixing roof sheets to steel and timber battens, roofing profiles and wall cladding, metal roofing and sheds. It is a hex head screw with a sealing washer, in C1022 hardened steel (SAE 1022 on the older sheets) with a Class 4 finish.

Like the other XGRiP screws, it has a short thread under the head that keeps the roofing clamped to the seal, so the seal stays watertight when the roof is walked on. Scratchguard protects the shank from scratching, which Hobson says improves corrosion resistance; most vmaX screws we carry have it (see the size table).

What vmaX screws fix into

• •Top hat battens: 0.55 to 0.75mm (Hobson's drilling capacity for the M6.2-13).
• •Steel purlins: 1.2 to 1.9mm (M6.2-13); Hobson says vmaX suits purlins up to 1.9mm thick.
• •Timber, pine and hardwood: 35mm embedment minimum (M6.2-13). Hobson's M6.2-11 timber pull-out values are for 32mm embedment.
• •Length: Hobson measures hex screws with a seal from under the head. On the M6.2-13, Hobson gives a grip length of 20.2 to 21.0mm for the 50mm screw and 35.2 to 36.0mm for the 65mm screw.
• •Thicker steel? Use a metal point tek screw with XGRiP, for which Hobson publishes pull-out values in steel up to 3.8mm.

vmaX screw sizes and packs

Both sizes are 6.2mm screws with a 5/16 inch hex drive: M6.2-11 has 11 threads per inch and M6.2-13 has 13, both coarse by Hobson's definition (up to 16 TPI). Select a row to open it in the selector, then pick the colour. Most come with Scratchguard; some coloured M6.2-13 screws also come without it. Pick Scratchguard or Without Scratchguard in the selector.

vmaX pull-out values

Hobson publishes laboratory pull-out values for each vmaX size in the steel or timber shown, and they hold only for that material. Hobson notes safety factors should be considered for design and actual pull-out loads may differ depending on the base material. It gives no edge distance, spacing, sheet pull-over or wind uplift figures: the fixing pattern for roof sheeting comes from the sheeting maker's installation guide or the building designer.

• •Screw strength (M6.2-11): torsional 10.9Nm; tensile 16,550N mean and 15,450N characteristic; shear 9,950N mean and 9,250N characteristic.
• •Screw strength (M6.2-13): characteristic tensile 16,609N, shear 9,134N, torsional 15.7Nm.

vmaX colours: which size comes in which colour

Head colours as Hobson lists them (the names in brackets are the New Zealand names Hobson lists on its vmaX colour sheet, shortened here for Smooth Cream and Thunder Grey). Not every colour comes in every size: select a colour to open it in the selector. Hobson lists Bushland, Wilderness, Loft, Headland, Sandbank, Pale Terracotta, Blue Ridge, Plantation, Primrose and Stone as discontinued COLORBOND colours, painted on request, so ask us before ordering these. Hobson's warranty covers the screw, not the paint. COLORBOND is a registered trademark of BlueScope Steel Limited.

Class 4 coating and warranty

Class 4 is a corrosion class for self-drilling screws (AS 3566.2). Hobson's vmaX sheet says the finish suits ISO 9223 category 4 environments, and its finish guide describes Class 4 as a 38 micron mechanically galvanised coating for external use in severe marine environments. Hobson's self-drilling screw warranty gives these periods:

• •Hobson's warranty covers the exposed head and washer only, for screws fitted with a screw gun to its instructions and washed with fresh water every six months (C2, C3) or every three months (C4, C5).
• •Class 4 is covered up to C4. Hobson does not recommend it in very severe marine (C5) sites, where only 316 bi-metal is covered (see roofing screws). Extreme (CX) sites need Hobson's written confirmation; ask us if you are unsure of your category.

How to fit vmaX roofing screws

1. Fit a 5/16 inch hex nut setter in a cordless screw gun set at 2,200 to 3,000 RPM. Hobson does not recommend impact drivers.
2. Place the screw on the crest at the fixing position, square to the sheet.
3. Apply consistently firm pressure while the screw drills.
4. Take care not to overtighten: Hobson warns that sealing washer damage could result. As general practice, stop when the seal is pressed onto the sheet.
5. General practice: brush the swarf off before you leave the roof.

vmaX roofing screws in Adelaide

Allmat supplies vmaX roofing screws, XGRiP tek screws, stitching screws and nut setters to roofers, shed builders and trade across Adelaide and South Australia. Add them to a quote with the rest of your list and we will price the lot.

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