Richard Dunn, who has 40 years’ sub-contract engineering experience, recently set up Overstone Engineering (near Coventry) to undertake small-batch manufacture and project work that other sub-contractors and OEMs may consider
“a nuisance, as they interrupt production”.

However, when Mr Dunn was looking to buy a new three-axis vertical machining centre (VMC), the entrance to his factory was the main issue, as the door lintel is only 2.2m from the ground.

After researching various options, he found that the recently introduced Hurco VM5i from High Wycombe-based Hurco Europe Ltd (www.hurco.co.uk) is less than 2m high with the ram lowered; and while this machine has a compact footprint (slightly over 1.6 x 2.2m), it has a relatively generous work envelope of 457 x 356 x 356 mm.

The machine, which has a BT40 spindle, was installed in January and joined existing machines that include a laser profiler (used for prototyping work and producing jigs and fixtures), a flat-bed CNC lathe with 1m between centres and capable of turning parts up to 300mm in diameter, and a machine for 3-D printing resin models.

Mr Dunn said: “I could not offer sub-contract machining services during the two-year exclusion period that applied after I sold my previous company — Drurys Engineering, in Hitchin. Now that I am free to re-enter the industry, I have been re-equipping, and I chose the Hurco VM5i for its size and capability.”

Overstone Engineering’s target market is the design, production and assembly of items that typically ‘disrupt’ activities on other manufacturers’ shopfloors. This often involves machining prototypes in ones and twos, small-volume milling and turning, plus electro-mechanical assembly.

The company also provides advice — and an engineering service — to designers, entrepreneurs and inventors.

Painless training

Shortly after the VMC had been installed and training had been completed at Hurco’s technical centre — a process described by Mr Dunn as “painless” — a contract was won for the production of a robotic test rig for non-destructive testing in the aerospace industry.

Overstone Engineering assisted in the design of the rig, working closely with the customer throughout all stages of its production. Since then, many contracts have been completed on the VM5i; these have involved a variety of materials — ranging from nylon and aluminium to phosphor-bronze and steels.

The most recent contract was to produce a single assembly made largely of phosphor bronze (for an unspecified application); and while most of Overstone Engineering’s work is programmed directly at the control using Hurco’s conversational programming software, in this case it was simpler to export a DXF file from Mr Dunn’s OneCNC CAD package and use the DXF facility in the Hurco control to generate the cutter paths automatically.

Mr Dunn says: “Besides its compactness, another benefit of the Hurco machine is the high level of technology built into its control software.

In addition to having the option of a module that allows native handling of DXF files, it can accept externally written G-code for milling 3-D freeform surfaces.

Hurco’s Ultimotion software was supplied as part of the overall package, and this gives fast motion that is smooth and dynamic — and exceptional for such a cost-competitive machine. This software greatly helps to reduce cycle times and improve surface finish.”

Throughout his career, Mr Dunn has amassed a vast amount of engineering knowledge and experience, most notably in the aerospace, oil and gas, Formula One and security sectors. He also has a long list of contacts in manufacturing companies that range from sole traders to multinationals.

“Many in my position would have retired early, but I missed production engineering and decided to go back into subcontracting full-time. If things work out as planned, I will offer an apprenticeship to an aspiring engineer, so that I can pass on my knowledge.”