Hexagon Set Screws

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Fully threaded hexagon head set screws, also called set bolts or tap bolts, to ISO 4017 and DIN 933. A2 (304) runs from M2 to M39 and A4 (316) from M2.5 to M42, and many A4 sizes come in both property class A4-70 and the stronger A4-80.

The thread runs the full length of the shank, the right choice for blind holes, thin material or any joint that needs thread engagement along the whole shank. Use a part threaded hex head bolt where a plain shank should sit in the shear plane.

Frequently asked questions

What is a hex set screw?

A hex set screw is a hexagon head screw threaded along its full length, made to ISO 4017 or the older DIN 933. It is also called a set bolt or tap bolt in the trade. Simfix stocks them in A2 (304) and A4 (316) from M2 to M42. Use it where you need thread contact along the whole shank, such as blind holes.

DIN 931 vs DIN 933: what's the difference?

DIN 931 (ISO 4014) hex bolts have a plain, unthreaded shank under the head with threads only on the lower section. DIN 933 (ISO 4017) hex set screws are threaded along the full shank. Choose DIN 931 when the plain shank needs to sit in the shear plane of the joint; choose DIN 933 for blind holes, thin material or full thread engagement.

What sizes of hex set screw does Simfix stock?

A2 (304) from M2 to M39 and A4 (316) from M2.5 to M42, in lengths from 3mm to 250mm depending on diameter. Many A4 sizes come in both A4-70 and the higher strength A4-80. Not every length is listed at every size and grade; check the individual product listing and current availability.

Can I use A2 stainless set screws outdoors?

Yes. A2 (304) stainless steel gives good corrosion resistance for indoor use and general outdoor and inland work. It is not the right choice near the coast, around pools or anywhere exposed to salt or chlorides; use A4 (316) in those environments, as it contains molybdenum that resists chloride pitting.

Sizes, grades and pack quantities vary by product type. Check the individual product listing for the exact specification and current availability.