When David Swaffield started his own subcontract machining firm, DWS Engineering in 2006 after gaining a mechanical engineering apprenticeship in Crewkerne, he started out using manual machines, progressing to CNC prismatic machining in 2009 and fixed-head CNC turning the year after.
Frustrated at not being able to find pre-war BSW threaded nuts, bolts and other components for the family-owned 1923 Aveling and Porter eight-tonne steam roller he was refurbishing, he decided to make them himself, leading to the inauguration in 2017 of another company, Historic Threads. It was then that Mr Swaffield discovered the capabilities and production potential of CNC sliding-head lathes from Citizen Machinery.
During the Second World War, the diameters of Whitworth threads were reduced to save metal. It is easy to obtain the later sizes, but the original larger varieties used to be scarce and difficult to source. That was until Mr Swaffield identified a business opportunity through steam-driven vehicle enthusiasts.
Now a vast range of legacy threaded components from the biggest Whitworth to the smallest BA (British Association) size and everything in between, is manufactured by Historic Threads. This business now accounts for 60% of turnover. Despite its recent inception, the company is probably the largest stockist and supplier of pre-WWII threaded components in the world.
Although nuts, bolts, studs and pillars tend to have a small length-to-diameter ratio and can be satisfactorily produced on fixed-head lathes, Mr Swaffield learnt the benefits of sliding-head turning. In particular, that gang tooling allows short parts to be produced faster and the lathes are additionally capable of turning shaft-type parts if required. His father-in-law owned a subcontracting company and he was a user of Citizen sliding-heads.
In 2017, the first Cincom L32 was purchased to produce thousands of nuts and bolts every week. It was recognised that in-cycle milling and other prismatic operations would be useful for machining more complicated components, so a second-hand Cincom M32 with live tools arrived in March 2021.
In March, the steep rise in demand for the legacy threaded components led to a third sliding-head lathe being installed, this time a new Cincom L32-VIII LFV. The modern machine has been supplied with an expansion kit to enable the nominal 32mm bar size to be increased to 38mm, allowing for instance a 3/4-inch nut to be turned from round bar.
Shortly after the machine was delivered, Mr Swaffield received DWS Engineering’s biggest ever single order for the supply of brass, aluminium and stainless steel parts from 10 to 20mm in diameter for use in the assembly of make-up brushes and pencils.
The latest Cincom is ideal for fulfilling this contract. For example, the LFV chipbreaking software avoids stringy swarf when drilling a 100mm long, 8.5 mm diameter hole down the centre of a 10mm diameter stainless steel pencil.
LFV is also proving useful in avoiding birds-nesting when producing plastic components, such as a batch of 2,000-off, 20mm diameter black Delrin spacers that went through the shop recently.
