A new twist on the old screw head

Once you’ve used Uni-Screw you won’t want to use traditional screws again.

It’s the 1930s in the US. Henry Phillips buys the idea of a recessed screw head from an inventor named JP Thompson, develops it into a workable form and founds the Phillips Screw Company in Oregon. He calls every screw manufacturer in the US and is told his screw cannot be made.

But he persists, and eventually finds a company prepared to manufacture his screws. Today, the Phillips screw and its sister, the Pozidriv (developed in the late 1950s), can be found in virtually every toolbox and piece of equipment around the world.

Now fast-forward to Sheffield in the early 1960s. Tim Brooks is browsing through some engineering patents when he spots one from a French inventor for a recessed screw head using a three-tier design that requires just one screwdriver for all sizes of screws. Brooks makes some punches by hand to form the recess in the screw heads and produces a batch of screws to show that the idea will work. But everyone tells him they are impossible to manufacture commercially — the cold forging technology of the day just isn’t up to the job.

Persistence pays

But Brooks persisted. And last December, nearly 40 years later, Birmingham fastener distributor and maker Forward Engineering, with an annual turnover of £6m, launched his Uni-Screw under licence. Today, telecom companies to white goods manufacturers are queueing to get their hands on samples.

One of the benefits claimed for the Uni-Screw is that it eliminates a drawback inherent in Phillips screws — ‘cam-out’, which occurs when the tapered screwdriver jumps out of the screw head recess under excessive turning force.

The Uni-Screw is being marketed as a replacement for all slotted, Phillips, Pozidriv and Torx fasteners including wood screws, self-tapping screws, and bolts. It uses just one screwdriver for all sizes between M2 and M12. The driver’s three-tier, concentric hexagonal shape ensures that even on the smallest screw sizes, one tier engages the punched recess in the screw head at six points. And on the biggest, all three tiers are engaged, giving 18 points of contact, compared with six in a Torx, four in a Phillips or Pozidriv, and two in a traditional slotted screw head.

The Uni-Screw’s high precision — its shape is claimed to be accurate to within 3° — eliminates cam-out and means that minimal force is required to keep the driver in the screw recess.

Appropriately enough, one of the companies that has expressed interest in the Uni-Screw is Dyson, itself famed for its inventor’s doggedness in overturning conventional wisdom to launch the world’s first bagless vacuum cleaner.

According to Martin Cleaver, director of Forward Engineering, the Dyson factory uses just one size of screw and one size of screwdriver. But with the Uni-Screw, says Cleaver, its designers could have the flexibility of a range of different screw sizes, yet still need just one driver. Dyson is currently evaluating samples of the Uni-Screw.

There are four members on the Uni-Screw team — Brooks, a former quarry manager; Harry Robinson, a former technical book publisher who backed Brooks from the start; Anthony Williams, a financier; and technical adviser Jonathan Frost.

The latter is a semiconductor physicist and former lecturer at Sheffield Hallam University. He had been doing European-funded work on high-speed machining when Brooks approached him for advice. He says he was so impressed with Brooks and his ideas that ‘I bought myself some of the company’.

The company has an ‘incremental patent’ pending to protect its developments and has licensed manufacture and distribution of the Uni-Screw to Forward Engineering. The eventual aim is a joint venture between the two.

Machining expertise

Forward Engineering has spent the past year using its expertise in modern machining and cold forming technology to develop the punches and drivers to bring Brooks’ ideas to fruition. To make the screws, steel wire is cut to length, the heads cold formed and the recess punched in. The blanks are then transferred to a cold rolling machine to form the thread. The screwdriver blades are produced on CNC machines. Forward Engineering is aiming the Uni-Screw at the white goods industry and the DIY sector. It has samples on trial at shower maker Triton and fridge maker Candy, as well as a number of telecoms companies. The US government has also taken some samples.

The company is also developing a Uni-Screw kit for the DIY market for sale through the big chains. Cleaver is negotiating licensing deals with other UK fastener makers. ‘Everyone has got one screwdriver in their house, whether it’s Pozidriv or slotted,’ says Cleaver. ‘But for most jobs you need more than one. We hope people will still have one screwdriver, but that it will now be a Uni-Screw. Once you’ve used Uni-Screw you won’t want to use traditional screws again.’