Being in business for 50 years is a remarkable milestone for any company. As many small and medium-sized business owners will know, it takes a lot of hard graft to get things moving, growing and running smoothly. However, the 50th anniversary is exactly what MTA Queensland member Diff Lapping Qld is celebrating in 2018.

Based in the Brisbane suburb of Kedron, Diff Lapping Qld has been offering its services to the public and to industry since it was founded in 1968 and for many of those years it ran under the guidance of Charlie Serchen – a name members may recognise as Charlie was, for many years, a Board member of MTA Queensland and Chairman of the Association’s Automotive Engineers Division.

Now owned and run by Carl and Vicki Tattam, Diff Lapping Qld continues to prosper, offering its unique service to customers both national and international, and its long and successful history is one that proves that a focus on delivering a service and product that is second to none will always be successful – if you’re the best at what you do, customers will come. Another few decades could easily be on the cards.

Like many businesses, Diff Lapping Qld’s name reflects the service it offers. While the company’s services include differential parts, axle straightening, vintage and veteran vehicle parts and repairs, gearbox repairs and parts, and the sale of Drivetech 4×4 parts and accessories, it is diff lapping for which it is renowned.

So, what is diff lapping? Well, it concerns the service and maintenance of a vehicle’s differential, but before we go any further, it’s probably worth reviewing exactly what a differential (diff) does.
While there are many varieties of diffs, they all essentially boil down to one job – it is a device that allows one input to drive two outputs at differing speeds. In a vehicle, this means it allows for one wheel to turn faster than the other while they both receive engine power. This is important when taking a corner, for instance – a situation where the outer wheel rotates faster than the inner wheel.

The diff works through a system of gears that interlock and engage to adjust the power and speed being delivered to the drive wheels. Given that all power to the drive wheels comes through it, a diff in perfect working order is vital to the smooth running, handling and performance of a vehicle – dodgy gears in a diff affect the performance of a vehicle and can be irritatingly noisy.

And that is where diff lapping – the process and the company – comes in.

Keeping the gears of a diff in excellent condition is the name of the game and ‘lapping’ is the process that is used.

In general, lapping is a process during which two surfaces are rubbed together with an abrasive – a solution of silicon carbide and oil in Diff Lapping’s case – between them. In the case of a diff, it is used to make adjustments to the tooth profile and contact points and improve the surface finishing – removing high spots to obtain even and consistent surface contact.

“The lapping process is basically about smoothing the surface of the gears, getting the contact pattern in the right position to provide long-lasting and quiet operation,” says Carl.

“Gears can get unevenly worn and through the lapping process we can smooth out worn gears and reposition the contact pattern. It’s a precision task and there is a lot of operator input into getting the right result.”

The range of gearsets that Diff Lapping Qld can work on is broad – anything from 4 to 18½ inches – and the company’s customer base is equally broad.

“We have had gears sent to us from NZ and from the UK for lapping,” says Carl. “And we do a lot of work for various OEM manufacturers.

“We often lap brand new gears because those gearsets are not necessarily quiet when manufactured. We also lap second-hand gearsets to give them another life and reclaim a lot of gears that you can’t buy anymore – quite a lot of old and vintage stuff. For example, we recently finished working on a 1912 Argyle, which I believe is one of only two left in the world.”

Central to the work that Diff Lapping Qld do is a Gleason Lapping Machine.

It is an amazing piece of equipment. Built in 1936, the Gleason is not exactly the sleek piece of machinery you might expect in a 21st century business but, as the old saying goes, ‘If it ain’t broke, don’t fix it’ and the truth is that this glorious piece of 20th century engineering is just about the best piece of kit for the job.

“That machine is essential,” says Charlie. “It can lap almost any differential crown wheel and pinion and on several business trips to factories in Japan in the 1990s I observed identical machines sitting amongst other specialist lapping machines. When I asked why, I was told this old one was the most accurate!”

“The machine may be old, but it is still the perfect machine for the job” adds Carl. “We manufacture different mountings and plates to fit a wide variety of gearsets – everything from a 4 inch to 18½ inches – and it copes with that range no problem.

“Of course, it’s not just a case of putting a gear in, pushing the button and walking away. To get the best result out of the gearset comes through experience, and that is what we have. I don’t think there are many people who offer the service we do.”

A STORY 50 YEARS IN THE MAKING
The Diff Lapping Qld story actually starts before 1968, and in a different State, when Charlie Serchen’s uncle, Jim Liprini, having recognised that the differentials in the Holden cars he was using in his taxi business could use some improvement, saw a gap in the market and set about creating a differential assembly business at his workshop, called Modification P/L, at Surry Hills in Sydney.

“In those days the quality of finish on the mating surface of the crown wheel and pinion meant that drive noise was common,” says Charlie. “Lapping the gears meant the differentials could be set up to be much quieter and last longer. And that process was done not only on Holdens – all vehicles suffered from diff noise.”

After incorporating a local lapping business into Modifications P/L in 1966, Jim renamed the business Differentials P/L and a couple of years later established the Diff Lapping business in Brisbane under the management of Jim Milliner.

Charlie, who had served his apprenticeship at Modifications P/L in Sydney, and who had moved up to Queensland to work as a mechanic, joined Diff Lapping in Brisbane in the early ‘70s to work on diff assembly.

Located at a small shed in Red Hill, the Diff Lapping team consisted of just Charlie and Jim at the beginning, but over the next few years, as the business grew, the workshop was extended and more staff were brought on, including a teenage Carl Tattam.

In 1983, a new workshop was built at Slacks Creek and the business opened a second shop there.

In 1985, Charlie became a director of the company and in 1989, after moving to new premises at Kedron, the business was renamed Diff Lapping & Repairs and became a separate company from its Sydney parent with Charlie responsible for all aspects of the running of the business.

Charlie bought the business outright in 2003 and purchased a stand-alone building in Boothby Street, Kedron, that was more suited to automotive mechanical work. In 2007, the buildingat Slacks Creek was sold with Diff Lapping continuing to operate out of the Kedron site.

Which nearly brings us up to date, except that a bare bones timeline tells only part of the story.

Over the decades, thousands of people have had their vehicles improved by the service Diff Lapping provides; the business has been involved with the local community through sponsorships and other outreach programs; and hundreds of young people have come through the company’s workshops to work, develop a skill and learn a trade to build their lives around. That’s no small feat.

For Charlie, who left school in Year 10 with no formal training, the business is a monument to what determination and a good dollop of hard work can create and it led to his involvement with MTA Queensland and a place within the Association that helped him be instrumental in actions designed to advance the automotive industry.

Diff Lapping Qld is now in the hands of Carl Tattam and his wife Vicki, and a more experienced set of hands would be hard to find – Carl has been with the business for 37 years, the last six as owner. There’s more experience on the shop floor too, with four other technicians in the workshop with decades of diff work between them.

Having taken the opportunity to take over the business when Charlie retired, Carl says it was an easy decision to make.

“After being here so long, and knowing the ins and outs of the business, it was the perfect opportunity,” he says.

And it is, he adds, a great honour to be at the head of such a well-respected shop.

“It does make me extremely proud,” he says. “Quite honestly, it is a remarkable achievement for a business to be around this long.

“It’s the quality of the work we put out that counts. I don’t think you can be around for 50 years in business without producing a good quality job and we have a lot of customers, who have been with us for a long time, who continue to spread the word about us.

“And I hope the business will be around for another 50 years,” he adds. “I won’t be here then, but I’d like to think that the boys who are here will keep rolling with it. We’re instilling in them everything that we’ve learned over the years and hope that they will carry on their excellent work when the time comes.”

Source: Motor Trade E-Magazine (October Edition)

3 Oct 2018