STAINLESS STEEL HEXAGON HEAD SET SCREWS ISO 4017

Hexagon Head Set Screws ISO 4017 — ISO 4017 is the current international designation for the fully threaded hexagon head screw long known by its German national standard number, DIN 933, and for most practical purposes the two describe the same fastener: a hex-headed screw threaded along its complete shank, intended to grip via a tapped hole rather than a plain shank bearing in a clearance hole. It's the default screw across general engineering, machine building, construction steelwork, and maintenance work wherever a threaded hole in the parent material is doing the holding, and it clamps thin sheet or plate effectively since the thread runs all the way to the underside of the head, maximising engagement in a shallow tapped section. Grade selection is an environment and consequence question more than anything else: A2 handles the majority of dry, indoor, and moderately humid applications at a lower cost, while A4 is the better specification once the screw faces marine air, de-icing salt, washdown cleaning, or ongoing chemical exposure — its molybdenum content holds off the pitting and crevice corrosion that will, over time, compromise an A2 screw in the same conditions. As the actively maintained ISO standard, ISO 4017 fixes head dimensions, thread length, and tolerance class so that fasteners sourced from different manufacturers remain interchangeable, which is precisely why it has become the preferred reference on new drawings and specifications in place of the older DIN number. Choosing the right screw means matching diameter to the load path and the mating tapped hole, then setting length so enough thread engages in the tapped material to develop the fastener's rated strength — a working benchmark is engagement of around one to one-and-a-half times the diameter in steel, more in softer materials like aluminium or cast alloys. Where vibration resistance or higher clamping load per diameter matters more than assembly speed, the fine-thread version of this same screw family is worth considering instead.

FAQs
Are ISO 4017 and DIN 933 screws physically interchangeable?
Yes, in virtually all practical cases — the two standards are dimensionally aligned closely enough that a screw to either designation will fit the same tapped hole, spanner, or socket without issue, which is why supply chains stock them as equivalents.

How does ISO 4017 differ from ISO 4014 hexagon head bolts?
ISO 4017 threads fully to the head; ISO 4014 leaves a plain shank section below the head for bearing in a clearance hole. Choose 4017 for tapped-hole applications and 4014 where the joint needs a plain-shank bearing surface or better shear resistance.

What tolerance class does ISO 4017 specify?
The standard defines product grades that set permissible variation in thread and dimensional tolerance for different accuracy and surface-finish requirements; the applicable grade for a given batch should be confirmed against the manufacturer's specification sheet or the purchase order.

Is fine thread available under a related ISO designation?
Fine-pitch equivalents of the coarse-thread hex screw are covered separately — commonly specified under DIN 961 in stainless ranges — for applications needing higher tensile stress area or finer positional adjustment than the standard coarse pitch offers.