Medway Marble, a specialist in granite worktops and a long-time user of HepcoMotion linear motion products, says it has recently sold a stone-cutting table-type machine featuring HepcoMotion parts for nearly the same value as it was built some 12 years ago. In the years between, the machine has been exposed to an extremely aggressive stone cutting environment – grinding dust turns to an abrasive paste when it mixes with coolant water from the cutting wheel.
Established in 1990 by current owner Nick Browne, Medway Marble soon found considerable success in the manufacture and fitting of stone worktops, fireplaces and hearths. The company was initially subcontracting its cutting requirements, but in the late 1990s wanted to invest in its own saw.
Mr Browne explains: “To buy a high-end, large stone saw we were looking at anywhere between £35,000 and £50,000, while ones on the market for £20,000 weren’t good enough for our applications. I began to think that for about half this amount we could construct our own stone cutting machine.”
Looking around for a suitable linear motion system, Mr Browne was impressed with the innovative vee bearing and track design of HepcoMotion products, which he saw as a real market differentiator.
Mr Browne says: “All the other systems I looked at relied on conventional ball bearings resting on a rail, and by and large, were exposed except for a cap seal – but even that wears out. The HepcoMotion concept was different. The bearings operate on a vee slide, with the critical parts [the bearings] kept away from any contamination that results from the process. That’s where the HepcoMotion products really did win. Of course, they also offered a high level of straightness and were able to withstand loads.”
The table-type stone-cutting saw was used for processing granite slabs up to 1¾” thick using a 600mm diameter wheel. It featured two horizontal rails that facilitated a back and forth stroke of 2000mm. The only drawback was that airborne grinding dust would mix with coolant water from the cutting wheel to form an abrasive paste. This would subsequently descend on the mechanics below which included HepcoMotion GV3 linear motion/actuator and HDS2 heavy duty linear guide systems – used to move both the cutting head and sliding table.
Mr Browne states: “Yes, the grinding paste would hit the slide rail and the feed bearing face, but the design of the HepcoMotion products is such that it was almost academic.”
HepcoMotion vee guide systems are very tolerant of contamination, as opposed to roller bearings which often fail catastrophically following the ingress of dirt, dust or debris. This is because vee guide systems have a self-cleaning action, which means that any contamination is wiped away by the vee bearings as they run along the rail. The millstone principle is a good reference point, where flour eventually migrates to the outside of the stone as the corn is ground. Similarly, any dirt that lands on the vee rail will eventually get wiped away. The advantages are clear to see at companies such as Medway Marble where fine abrasive dust is omnipresent.
A further advantage is that once the rail starts to show signs of wear it can be adjusted quickly to remove any play and restore the running quality back to its original condition, thus costing nothing in replacement parts.
Mr Browne says: “The machine lasted for more than 12 years, cutting granite every day, with only a little adjustment for wear and a re-grease every eight months or so. I estimate that the machine cost around £7000 to make and we recently sold it for £5000 after all those years.”
Medway Marble has now sold its entire worktop manufacturing operation. Among its core business these days is the construction of machines that form and polish drainage grooves on granite worktops. The machines replace a previously manual, laborious operation with an easy, quick and repeatable process. Naturally, the machines rely on linear motion technology from HepcoMotion. To learn more, please visit www.hepcomotion.com.