Latest CNC shaft lathe, designed for the automated, high-precision, internal and external machining of large shafts and pipes, is machining hydraulic cylinders..

A new breed of CNC shaft lathe - purpose-built by Dean Smith and Grace of Keighley, West Yorkshire, UK - for fully automated, high-precision, internal and external machining of large shafts and pipes, is helping the resurgence of Precision hydraulic cylinders (PHC). PHC is a Cramlington, Northeast-based manufacturer of mechanical rams for the fork lift truck and earth moving machinery markets. Designated 'SE' (Special Equipment), the lathe incorporates a 4000mm length bed, Fanuc 18i control, and fully automated chucking and steadying equipment for rapid loading and set-up.

The delivery of the lathe marks a remarkable turn round for PHC, whose premises were levelled to the ground in a devastating fire in May 2003.

Over the last three years the company, starting from the floor up, has totally rebuilt itself, and, the loyalty it showed to its customer base has been, in the most part, fully repaid.

Now, with the commissioning of the Dean Smith and Grace lathe, the fortunes of PHC have 'turned almost full circle'.

The lathe has been specifically purchased for handling 240mm diameter x 4000mm long hydraulic cylinders for earth moving machinery.

Delivered in March this year, the lathe has certainly impressed the person chiefly responsible for recommending the purchase of the machine, industrial engineer David Smith.

Smith commented: 'Because of the specialised nature of the application and our requirements for automated loading, the lathe was always going to be a 'special' - and we asked several major machine tool manufacturers to quote.

Unfortunately, because the lathe was a virtual 'one-off', however, the quotes I received were, quite frankly, unrealistic and way beyond our budget.' He continued: 'I then noticed an application story in one of the machine tool magazines concerning a bespoke lathe manufactured by Dean Smith and Grace of Keighley and found the article quite interesting, so I decided to give them a call.' He said: 'From the outset, all of the staff at Dean Smith and Grace - from managing director Nigel Grainger down - was very easy to work with and PHC had considerable input in designing the lathe,' added Smith.

'The finished build standard rivals any machine tool on the market and most pleasing of all, it came in at a quarter of the price of some of its rivals.' The process for setting up the large cylinders is now operator friendly, so that the cylinders can be quickly loaded and set-up with just one operator, at a stroke slashing floor-to-floor times for what has historically been a difficult and labour-intensive task.

Assisting the quick loading and set-up, is a fully automatic SMW KCNS 400 hydraulic, quick release, chucking system; complemented by an SMW type SLU-Z-4 three-point roller steady with mechanical positioning.

The three-point roller steady can traverse the full length of the bed - under operator's control or automatically - to find the optimum position of support, while hydraulically operated jaws clamp to the workpiece or retract as required.

The chuck and steady work in conjunction with an automatic tailstock designed and manufactured 'in-house' by Dean, Smith and Grace.

The tailstock utilises hydraulic power and the lathe's rack and pinion drive to automatically position at pre-set locations programmed by the operator.

Other features of the 'SE' include: Sauter 12-station auto indexing VDI turret, slat-type swarf conveyor, Fanuc digital motors, precision ball screws and Vogel/Sterling automatic lubrication system.

Operator Mike Smith (no relation to David Smith) is impressed both by the accuracy of the lathe and the auto loading: 'With some 4m bed machines, there tends to be small dimensional discrepancies when machining end-to-end, as we are with the current job.

Not so with the 'Deans' - accuracy is absolutely 'spot-on'.

Also, the automatic chuck, three-point steady and tailstock work well together to make loading a very simple operation.' David Smith summed up: 'Having been in service six months, we are very impressed with the performance of the Dean Smith and Grace CNC lathe and it is proving ideal for the application for which it's designed.

Commissioning and service response have also been pretty good, and, all-in-all, the purchase of the 2817 x 150 'SE' has proved an excellent investment.'