Increased productivity, improved process efficiencies, reduced operational costs and consistent high part accuracies – Chesterfield Special Cylinders’ recent investment in new Puma 3100LSY multi-tasking lathe from Mills CNC delivers the goods on and across all fronts.
Mills CNC, the exclusive distributor of DN Solutions and Zayer machine tools in the UK and Ireland, has recently supplied Chesterfield Special Cylinders (CSC), a market-leading design and manufacturing specialist of high-pressure gas containment solutions for safety-critical applications and systems, with a new box guideway multi-tasking lathe.
The 10” chuck/102mm bar capacity DN Solutions Puma 3100LSY, equipped with a sub-spindle, Y-axis and driven tooling capabilities, was installed in a dedicated ‘large product’ machining zone within CSC’s’ 100,000sq. ft. manufacturing facility in Sheffield in February 2026 and is the first machine tool the company has acquired from Mills CNC in its long and illustrious 125 year history.
Since being installed, the Puma 3100LSY has been put through its paces machining relatively small (length and diameter) industrial cylinders that are used in a range of safety-critical applications in the aerospace and defence sectors. CSC is also trialling it to machine different sized, shaped and configured cylinder adaptors and adaptor components.
Cylinder manufacture
CSC’s industrial gas cylinders are used and specified by a growing number of domestic and overseas customers.
Depending on customers’ needs and application requirements, cylinders can be manufactured and supplied in a range of sizes (up to 12.5m in length) with different capacities (up to 3000L) and operating pressures (up to 1000bar).
The cylinders machined on the Puma 3100LSY are relatively small and are made from mild steel or alloy steel tubes, which once cut to size, undergo in-house hot forming and forging operations.
Once the forming and forging processes have ended, the cylinders are then machined to completion on the Puma 3100LSY.
Different machining operations here include the removal of mill scale, a hard bluish/black oxide layer that is created during the forming process on cylinder surface exteriors. The removal of this is a critical task as the presence of mill scale can negatively affect cylinder finishing operations, such as poor paint and protective coating adhesion.
Removing the mill scale is a difficult process that requires the right tooling, such as negative rake carbide inserts, and the use of a rigidly-designed machine, like the Puma 3100LSY.
Adaptor manufacturing
The Puma 3100LSY is also being used to machine differently configured adaptor parts (i.e., special high-pressure fittings, flanges etc.).
These parts, often with intricate features, are machined in relatively small batches from solid steel billets and are processed in one set up, making full use of the Puma 3100LSY’s multi-tasking capabilities.
New machine tool investment
CSC is an innovative and progressive company committed to continuous improvement and, as such, regularly invests in its people, equipment, systems and processes.
In 2025, the company audited and benchmarked its in-house turning capacity and capabilities in order to identify and rectify production bottlenecks and process inefficiencies which could affect future productivity, machine shop throughput, and lead time fulfilment.
The audit confirmed an issue with the company’s existing turning capabilities, specifically with one of its existing lathes which had resulted in it being side-lined.
“The lathe in question had been earmarked for machining our small cylinder products and adaptors, but it just wasn’t up to the task. The machine’s limited capabilities, combined with a lack of skilled operators on site, had resulted in us subcontracting our small cylinder and adaptor work out to third party suppliers.”
Adam Mellor, Production Engineer at CSC
Whilst this subcontract route provided a solution to CSC’s immediate turning issues, it did have some downsides. Primary concerns were the significant costs involved in subcontracting the work out, as well as the inevitable relinquishing of control.
“From both a cost and control perspective, we made the decision to bring this work back in house. To achieve this, we decided to invest in a new multi-tasking lathe.”
Adam Mellor, Production Engineer at CSC
New machine investment
Although the Puma 3100LSY lathe was delivered and installed in February 2026, the procurement decision-making process started some months earlier, with key production staff from CSC initially drawing up a comprehensive pre-purchase machine tool checklist that detailed several new lathe ‘must haves’.
“We knew that we needed a compact lathe with proven multi-tasking capabilities which would enable us to accommodate and machine our small cylinder range and adaptor parts, quickly, and in one go. We also made the decision, from an operator knowledge and familiarity perspective, to opt for a lathe with a Fanuc control as this was our preferred CNC control platform that would enable seamless program sharing across our machines.”
Jason Langton, Project Manager at CSC
Armed with its new lathe checklist, CSC approached the market to discuss its requirements with a select number of machine tool manufacturers/suppliers. One of the companies contacted was Mills CNC.
“Although we hadn’t previously purchased a machine tool from Mills CNC, our research revealed that the company was well respected and highly regarded.”
Adam Mellor, Production Engineer at CSC
“We were impressed with the depth and breadth of Mills’ machine tool range, and with the pre and after-sales services and support the company provides to its customers.”
Jason Langton, Project Manager at CSC
Following further in-depth discussions between CSC representatives and Mills’ sales and technical staff covering the technical capabilities, cutting performance, purchase cost and availability, the decision to invest in a new Fanuc-controlled Puma 3100LSY was made.
The order was placed at the end of 2025, with machine delivery, installation, and operator and programmer training occurring in February/March 2026.
Puma 3100LSY – a closer look
The Puma 3100LSY delivered to CSC was preconfigured to hit the ground running from day one and featured an auto tool setter, a LNS mist extraction unit and a BobCAD-CAM software package.
To increase the machine’s versatility and with future proofing in mind, the machine was also prepared with a programmable steady rest that would facilitate the machining of longer cylinders and parts.