CNC Machining Technology Saves Stranded Drivers

Automotive companies are getting ever more inventive in designing locking systems that prevent the theft of highly desirable aluminium wheels. But what happens when the key to the locking device is misplaced when the driver is stranded on a stormy night by the side of a road and can't remove the wheel - adding total misery to the inconvenience of a flat tire?

British innovation has scored again with Dynomec Limited, a small company in West Yorkshire, developing the solution to remove locking wheel nuts, voted ‘Best Product 2004' by Motor Mechanic magazine. The machining of components for the Locking Wheel Nut Remover is now carried out using a three-axis Colchester Tornado T8M from Colchestersales by the two inventors of the product who had no previous knowledge or conception of CNC machining technology.

The patented ‘universal' wheel nut remover is so simple it's brilliant, and has been adopted by breakdown rescue services, police, accident repair specialists, tyre companies and is a common tool in most garages up and down the country. Such has been the impact of the product for the UK scrapyard business, that prior to the tool being available only around a third of aluminium wheels were salvaged for resale. "Today this figure is approaching nine out of 10," says David Brain, who is one of the two inventive brothers who are partners in Dynomec.

Based in Castleford, Ronnie and David Brain actually caught a cold for taking their idea to the Far East for low cost manufacture. They quickly found they had little control over materials used, found large variations in the quality achieved by the production operation and became progressively frustrated at not knowing when the parts would turn up in the UK ready for sale.

So full of frustration and with UK subcontractors proving too costly, the duo decided to convert the garage at the rear of their shop into a production unit and installed the three-axis Colchester Tornado T8M with driven tools and integrated barfeed as the mainstay for most of their machining operations.

It was a critical decision. Both brothers had very little knowledge of CNC turning - let alone mill/turning - as Ronnie's background was as a mechanic for the Coal Board and David, was formally a foreman in a local engineering firm. Indeed, the inspiration for this ‘simple once you see it' rotary chisel based nut remover - that not only protects the wheel from damage while the nut is being removed, but also fits the hundreds of different locknut types including the latest high security hardened ‘non-destructable' developments used by the top car marques - came from helping a friend in 1999. He wanted a set of aluminium wheels from a Ford Fiesta in the local scrapyard and the yard owner promised if he could get the wheels off he could take them for free as the yard owner was more interested in the hubs and brake parts.

Back in David's workshop, the two brothers devised the system where a protective shroud/sleeve slips into the body of the wheel and over the locking wheel nut to act as a guide for the central hollow chisel shape cutter that has two opposed blades. The hardened reverse end which has milled spanner flats of the chisel is then hit with a hammer that embeds the cutting edge of the chisel into the locking ring or stud to create a large indent. This indent is then used as a drive slot that allows the nut to be unscrewed using a spanner, impact wrench or wheel brace while still being retained in the protective shroud.

The scrapyard owner was very impressed and wanted to buy the tool but Ronnie and David had other ideas and decided to hawk their idea around tool merchants. They quickly realised they had a winner, and bored with their jobs, decided to set up in business. Indeed, an order for 2,000 units from one of the UK's leading tool distributors meant the pair had to work over the Christmas holiday in their father's garage making the parts on an old centre lathe.

Today the device, which is now sold as a universal kit over the Internet or from advertisements, is a far cry from the scrapyard challenge tool. It has been completely redesigned to suit Tornado production, with help from the application team at Colchestersales' Northern Technical Centre. But the design still retains its simplicity and will accommodate all current locking nuts and studs - even the latest hardened variants designed to defeat would be non-keyholders.

The innovative pair dreamed up another simple solution to overcome the latest development by replacing the chisel edge with a soft tool blank that deformed to precisely fit the shape of the locknut to be unscrewed. This soft adapter is also turned and milled on the Tornado T8M.

Says David Brain: "We decided to buy the Tornado from Colchestersales for several reasons. It was a lot of machine for the money, and we knew the Colchester name from our schoolday metalworking lessons. The Northern Technical Centre at Heckmondwike is nearby and the sales and application people were very interested in what we were doing, they understood our lack of CNC knowledge and were prepared to do a lot of hand-holding and training."

He continues: "What other lathe suppliers did not appreciate was the extra initial help we would need. OK they gave three days training in with the purchase deal and from then it appeared to be almost like a taxi meter running, which put us off." Colchestersales has provided help when needed to program 40 or so different components machined so far, helped with tooling, and according to Ronnie Brain: "We are really appreciative of the Manual Guide i programming on the machine and the COLCAM off-line system which we can use in the quiet at the desk while the machine is working."

Ronnie Brain maintains: "It was a great confidence builder when programming to work on a single screen and we think nothing of interpolating different axes. Programming is a matter of filling in boxes, following the arrows, using cycles that we can define ourselves and because programs are shorter, we can edit conversationally using text and graphics."

Once the job is programmed, Ronnie Brain insists the cycles are very easy to follow with the 3-D graphics on the screen showing the tool tip shape, the axial and radial drilling and milling toolpaths are also simply depicted. "This really helps and we know exactly what is going to happen when we press the start button," he says.

According to David Brain: "The machine is run up to 18 hours a day producing up to 1,000 parts in a batch for the nine turned items that make up the tool kit. Also using the machine, the two partners have developed other products such as substitute wheel nuts and studs to overcome the safety issue of the car owner driving away having had the locknut destroyed resulting in a nut or stud missing from the wheel.

The two have even produced specially machined tee-nuts for another company on a subcontract basis involving in cycle heavy milling of flats. "The Tornado T8M is certainly a universal machine," maintains Ronnie Brain "and has brought everything under our control."