The term ‘eclectic’ can certainly be applied to the precision sub-contractor Lamb Engineering; its production includes manufacturing variable-pitch feathering propellers for the marine industry, work-holding solutions for a leading UK manufacturer, and a wide variety of general engineering components, including parts for custom motorcycles — a passion of managing director Larry Houghton.

At the heart of the Wiltshire company’s success is the design flair of Mr Houghton, who has won several awards for products he has created. A waterproof padlock that he designed and manufactured was chosen as one of the Millennium Products, while his custom motorcycle creations have gained world-wide recognition.

It was this creative ability that was put to the test when Lamb Engineering was approached to machine components for the Darglow Feather Stream propeller. The problems encountered manufacturing to the original design led Mr Houghton to completely re-work it, adding an external pitch adjuster that allows the pitch of the propeller to be fine-tuned in under 15min. The design changes resulted in a propeller that costs 25-30% less than comparable systems.

The machining of the components also threw up its own challenges; the blades are produced from heat-treated 316 stainless, while the bodies are machined from either billet or cast AB2 aluminium bronze. For machining these parts, Lamb Engineering relies on a range of machines from XYZ Machine Tools, Burlescombe (www.xyzmachinetools.com). Recent purchases include two turning centres — an XYZ 250TC and an XYZ TC400.

More capacity

Mr Houghton says: “The success of the propeller business has seen volumes grow considerably, making additional turning capacity a necessity. The accuracy of the turning centres was also paramount, as we have to machine the parts to tight tolerances; for example, the blade groove width is tied to +10µm and the body width to -10µm.”

Both XYZ turning centres use the Siemens 828D Shopturn control system. This features conversational programming that makes the setting, programming and production of the small to medium-size batches (the norm at Lamb Engineering) straightforward.

Moreover, the VDI turret offers the option of driven tooling at any of the 12 positions, making tool setting quick and simple; setting is further helped by the inclusion of an automatic tool-setting arm as standard.

Lamb Engineering added to its stock of XYZ machines as the business grew, moving from manual machines in 1994, through ProtoTrak-controlled mills to full CNC.

Moreover, all the machines that Lamb Engineering has bought are still in operation today (when the company submitted its first XYZ machining centre — purchased in 1996 — to a Renishaw Ballbar test, the results showed that it was deviating very slightly from the original specification and a simple software adjustment was all that was required to bring it back to ‘as new’).

While the propeller and work-holding components are Lamb Engineering’s ‘bread and butter’, it is Mr Houghton’s love of custom motor-cycles that has won him national and international acclaim. He builds these ‘works of art’ for himself and individual customers, one of whom uses his bike as the centrepiece of his living room.

The current project is the manufacture of a limited edition of JAP-engined motorcycles. The engines are machined complete at Lamb Engineering and are limited to 10 units a year.