Founded back in the mid-19th century by two brothers, to meet the demands of the burgeoning shipbuilding industry in Glasgow, Stewart-Buchanan Gauges continues to design and manufacture a comprehensive range of Pressure/Temperature Gauges, Needle Valves, Ball Valves and Manifolds. Now, in its third century of operation the company has redefined itself finding new markets and innovative ownership.

The business has grown over the years through a mix of organic and acquisition, the most notable merger being with Buchanan Thermometers to create the current company name. Now located in three factories covering 42,000 ft2 Kilsyth, Glasgow for the past 43 years. Therefore, it came as something of a surprise to the 160 employees in 2010 when the owner announced that he was selling the business. An even bigger surprise came when he confirmed that he would be selling it to them!

“This was a major milestone for the business and one that took a little bit of adjusting to,” says Sales director John O’Donnell. “However, we are now reaping the rewards with 2012 being a record year for the company. Fundamentally, the business didn’t change, but the added incentive of ownership focused our attention on new products and markets to grow the turnover.” Pressure gauges remain the company’s core business, but market share has increased with a move into the manufacture of manifolds, which are used in the oil & gas, power generation, hydraulic and food and beverage industries. These markets demand additional value added products, such as valves, which Stewart Buchanan Gauges (SBG) is now supplying as turnkey projects or stand-alone products.

This move to the manufacture of manifolds also brought with it new challenges with more exotic materials needed for their construction, such as Hastelloy, Inconel, Super Duplex, Titanium and, in particular, 6MO which is an super austenitic stainless steel with an increased molybdenum content. 6MO also contains Nickel and Copper to provide excellent resistance to pitting and crevice corrosion, which is vital in subsea and other extreme areas of operation.

Machining of these alloys posed its own issues in terms of longevity of cutting tools and metalworking fluid, production engineer Iain Connacher undertook a review of the cutting fluids used in SBG which led to Iain beginning the process of researching alternative suppliers. “Looking around it was apparent that there were numerous companies supplying coolants, with each company highlighting their own advantages,” says Iain Connacher. “Fortunately, it was at this time that Craig Wieland from Jemtech (UK) called and introduced me to the Blaser Swisslube range of products. The promise of increased tool life, improved surface finish and the lack of biocides in some of their products, certainly captured my attention.”

Jemtech was invited to trial BlasoCut 935, which was developed for the type of materials being machined at Stewart Buchanan Gauges. “Blasocut 935 is a mineral-based oil and his marketed as a bio-concept product, as the blend contains a natural element that controls any bacteria that may form in the sump. This eliminates the requirement to use biocides, a major advantage for us in terms of health and safety of the operator and manufacturing environment. Also, by eliminating any superfluous chemicals from the metalworking fluid Blaser ensures that you get more oil per barrel making it more cost-effective.” says Iain.

The first machine to trial Blasocut 935 was a Mori Seiki machining centre, where an immediate positive effect on tool life and surface finish was seen and power consumption was reduced by 3 per cent when using indexable insert drills. Another benefit was when drilling with Hsco (high speed steel) drills: “The machine operates on a double shift system and both operators assumed that the other was re-grinding the Hsco drills, when the reality was that neither of them were, the tool life had simply improved dramatically. This was more evident when machining 316 stainless steel.”

It wasn’t just the performance of cutting tools that saw an improvement following the switch to Blasocut 935. The Mori Seiki machine is equipped with a pallet changer and with the previous coolant the pallets and fixtures would start to rust after a short period of time. Even when operators paid special attention to cleaning and drying, along with a coating of WD40 did not cure the problem. Since the introduction of Blasocut 935 the need to spray any fixtures/equipment is no longer required, saving valuable man hours and avoiding damage to both machine tool and fixturing.

Iain then turned his attention to the turning section and a Tornado CNC lathe that is only used to machine one particular component. This machine had established tool life figures of 120 components set within the program. With the Blaser metalworking fluids the inserts showed minimal wear when that point was reached so the bar was raised to 150 off. At this point the only insert showing wear, resulting in some parts being out of tolerance, was the finishing insert. This was overcome by adjusting the cutting data and increasing the insert radius changed from 0.4 to 0.8. The result is that this part can now be machined, unmanned overnight, without any intervention with a target tool life now set at 275 components.

The success of these initial trials has resulted in a program to change over all of the machine tools at Stewart-Buchanan Gauges. A process that will be done in stages to minimise disruption to production. Jemtech (UK) will be assisting with this process and have set up regular service visits to monitor coolant quality and strength.

Performance and productivity gains are one thing, but as an employee-owned business everyone is aware of the bottom line, so Iain Connacher has calculated the potential savings that will be made as a result of the change to Blasocut 935. “We are looking at a 20 per cent saving on our tooling costs, which equates to an annual saving of £32,000. Added to this will be the reduced cost of metalworking fluid, due to the extended sump life, which spread over a two year period to account for the initial changeover costs will amount to a further saving of over £33,000.”

Further savings will be made as the above figures do not take into account any reduction in downtime created by the requirement for fewer tool changes and regrinds and the elimination of the need for fungicide and bactericide additives.  Also, it is expected that top up concentrations for Blasocut 935 will be reduced to between 1 and 1.5 per cent, which will lead to a further reduction in metalworking fluid costs.