Products + Tools

Technifast Ltd has expanded its specialist fastener portfolio with a range of self-cutting thread inserts, designed to provide a high strength thread in plastics, wood and soft metals.

The self-cutting inserts have an internal and external thread and are supplied in a choice of steel, stainless steel 303 or stainless steel 316, with a range of thread sizes.

Design of the inserts began after the firm was approached by a professional diver who needed a secure means to bolt down equipment, which included gas bottles and diving gear in a RIB (Rigid Inflatable Boat). The diver initially enquired about Technifast’s 300 series inserts in marine grade stainless steel, but after discussing the customer’s needs, Technifast’s production team soon established the grip of these would not be sufficient for the chaotic environment of a fast RIB in a choppy sea. The risk of a pressurised gas bottle breaking loose within the confines of a fast moving boat was something to be avoided.

The production team identified that a blind insert would be a better solution as it would prevent any water ingression into the hull cavity and wood sandwich layered within the fibreglass, so as not to drastically reduce the grip of the insert, cause wood rot and compromise the integrity and strength of the fibreglass.

“We identified a design that incorporated a deep and coarse self-tapping thread to provide sufficient grip; a minimum of 15mm usable internal thread; a shoulder at the top to enable a good watertight seal; and 3 interruptions in the thread to remove the host material cleanly on insertion,” explains John Garner, senior engineer at Technifast.

John continues: “We manufactured a prototype batch with an M10 internal thread and sent the diver some samples to test. He reported back to us that they functioned perfectly and placed an order. We then manufactured a longer M12 version that he also tested successfully for us. Having a customer you can liaise with over design and function, who can then help test and develop products, is invaluable. This is something we try hard to cultivate in our manufacturing department as it’s the best way to learn what our customers need, and most importantly, where we can improve on our product range for them.”