Bristol/Allen Countersunk Head Screw UNF Bcp UNF

The Bristol/Allen countersunk head screw is an industrial fastening element with Bristol or Allen drive, used in joints where the head must sit flush with the surface. TECTUL offers it in carbon steel, UNF fine inch thread, and UNF thread reference when applicable to the product design. Selection must start from the thread, usable length, head type, and compatibility with the existing threaded part or nut. Unlike the Bristol socket head cap screw, it requires countersinking in the part to house the head. For this lot there are actual sizes such as 1/2 X 1.1/2 to 3/8-24 X 2, sold by unit. It is an option for maintenance, fabrication, equipment assembly, spare parts, and assemblies where precise, removable fastening with good tool access is required.

Available sizes

Installation recommendations

• Confirm whether the required thread is UNC, UNF, or metric before requesting a quote; do not mix pitches even if the diameter looks similar.
• Use a Bristol/Allen key in good condition and fully seated to avoid stripping the internal socket.
• Verify that the length does not bottom out in blind holes and that it allows proper seating of the head or tip.
• On stainless steel, avoid contamination with rusted tools and consider compatible lubrication to reduce galling.
• When the joint is critical, define the torque according to the drawing, base material, and project installation procedure.

We dispatch to Bogotá, Medellín, Cali, Barranquilla, and all of Colombia. Request a quote via WhatsApp for the Bristol/Allen countersunk head screw, indicating size, thread, material, quantity, and whether you need equivalence with DIN, ISO, or inch thread.