Premier is one of the UK’s largest providers of specialist deep hole drilling, gun drilling and honing services, and  can gun drill diameters from 2.5 up to 38 mm, to a depth of 2000 mm from one end or 3000 mm through from both ends. A total of 22 machines, single and multi-spindle types, provide the capacity for central holes in round workpieces, while four knee-type machines cater for prismatic and off-centre work.

Customers of the 35-strong company operate in the most demanding engineering sectors, including aerospace, motorsport, offshore and petrochemical, medical and hydraulics.

Managing director, Stuart Grant, explains: “We started looking for extra capability in 2006, initially to meet predicted ramp-up demand for the Boeing 787 Dreamliner programme. The decision was taken to invest in a 2 - 3 metre bed machine that could ejector drill up to at least 150 mm diameter, because the size suited certain aerospace programmes and we had an increase in the demand for components with larger bores from other industry sectors, specifically the oil and gas sector.”

Having seen a lot of machines that were simply not up to the job, Premier’s three month search came to fruition with a 4 metre Ryozan machine being sourced from a factory in Eastern Europe. While the work did not call for a 4 metre bed machine the management team decided that the additional capacity would take the company into a different league.

Yorkshire Machine Tools sourced the machine and were given the project of refurbishing it to a specification set by Premier. Part of the specification included workpiece counter rotation, so that the machine would duplicate the ability of the company’s smaller ejector drilling machines.

Having purchased the machine carcass Yorkshire Machine Tools began refurbishing the guide ways and fitting new ballscrews, as required. A new 8000 litre coolant tank was fabricated, and the oil pump and seals was also refurbished to safely handle the high pressure required during the ejector drilling process. The electrical control system and axis drive motors were renewed to meet current industrial standards and to provide Premier with the level of process control it expects from all of its machines.

Due to the complexity of the machine rebuild the project run slightly later than planned, but this worked out well as it suited Premier’s plans to re-organise its shopfloor, remove redundant machines and equip it ready to support the size of raw material that would be handled. This included improving its building infrastructure to facilitate better material workflow. For example, as the new drills are capable of drilling up to 250 mm diameter by 4 m long, the overhead cranes had to be extended and increased in lifting capacity to 4 tonne. Over £100,000 has been invested in improvements to the facilities.

Stuart Grant says: “The new machine was up and running before the end of February and the initial plan is to load it with existing routine work to prove it out. A new operator has been taken on to cover this area, and is currently undergoing process training due to the specialist nature of the deep hole drilling process.”

A strategic plan was made to back up the 4 metre machine with a shorter bed version of the same machine, and a 2 metre machine was ordered in September 2007. That machine is already being commissioned and will be ready for delivery in April. The shorter machine will also be able to ejector drill up to 250 mm diameter and has the same tool interface so that the tool tubes from each machine can be interchanged. And, both machines feature 37 kW motors driving the heads and 30 kW motors on the counter rotating heads.

The ejector drilled Boeing 787 components make up engine nacelle actuation equipment, which is a ‘full control’ component with Premier procuring the raw material, arranging heat treatment, drilling and machining to a prepared blank stage for the customer.

“The plan is to prove out the work for the Boeing 787 project, which will end up on the 2 metre machine, taking it to full capacity by the end of the year as the build ramps up. The machine that this work is currently loaded on will address an increase in demand from a customer in the oil service and exploration sector. Effectively, the 4 metre machine will be kept for new business and is particularly suitable for oil exploration/extraction drilling parts such as drill head, feeder tubes and collets, as well as aircraft landing gear parts that are larger than we could previously handle,” Stuart Grant says.

Due to its complex nature the tooling tubes and drill heads are expensive and is purchased to suit the application, tubes only cover a 2 mm diameter range and bores have to be done in several passes. Stuart Grants states: “Even with the power available on these new machines the most they can take out in one pass is 100 mm diameter, so its at least three passes to achieve 250 mm diameter. The tool tubes we use offer some flexibility as they can be threaded together to extend the tool, and are compatible with both machines.”

With 14 machines of various configurations, the honing capability has also recently been expanded following equipment investment. Premier now offers internal surface honing up to 250 mm diameter by 4000 mm long. The CNC turning capacity has also been increased with two new Haas CNC lathes having also been purchased to meet an increased call for aero actuation parts as well oil and gas components. An SL-30 was delivered in February and an SL-30 Big Bore long-bed version will be installed in April to carry out complex external turning operations.

“Due to the increase in the Boeing project overlapping a current CFM project that will eventually be sent to a lower cost manufacturing base, we will have some spare capacity available by the middle of 2008,” concludes Stuart Grant.