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A passion for modelling

Peter Fraser has long retired from the extraction and contracting industries, but his legacy lives on with his modified Kumbee Hammermill, still in use around New Zealand and many other countries. 
Alan Titchall talks to Peter at his home about his invention and his perfectly scaled models of crushers and quarry equipment.

CONTRACTOR MAGAZINE first wrote about Peter Fraser (June 2016) through ex-editor Gavin Riley, who is now living in the same suburb of Havelock North.

More recently, Peter’s name came up again through our Classic Machines writer and machinery historian Richard Campbell. When Peter rang him, while researching details of a LeTourneau carryall and sheeps-foot roller, they discovered they had something in common. They are both keen on models of machinery and equipment.

Peter and his father Jock were well known industry identities in the Hastings area where they operated a contracting and transport business, John Fraser and Sons Contractors, plus an alluvial quarry at Mere Road at Fernhill, Hastings.

In January 1967 Peter and his father found out there was a road to be built that would provide access to the Ngaroro River, so they traipsed across open country in Fernhill looking for a block of land near the river.

They found survey peg No 13, Jock’s favourite number. They walked the boundary, found the corner and Jock said: “This is mine!” They also bought blocks 10, 11, 12, set up a small plant and crushed metal for the first section of the Hastings motorway, now known as the expressway. They didn’t tender for the supply of metal for the second section because of the way the contract was set up. Peter suggested to his Dad that they just sit back, which they did, and in the end they inherited all the cartage because they owned the right vehicles. John Fraser and Sons had become the biggest contracting company in Hastings.

John Fraser and Sons merged its interests in 1972 with HB Transport Holdings, and Peter was assigned the job to design and build Fraser Shingle on the land at Fernhill. He was 36 years of age.

Now, in his early 80s, he still remembers every detail of the original operation. Eventually, on behalf of the Holding Company, Peter bought out all of the other plants in the area because the capacity of Fraser Shingle was well over 100,000 tons a year.

“It was a very successful operation,” he recalls, “but, sadly, due to the 1987 economic crash HB Transport Holdings board sold the quarry in 1987 to Milburn [now Holcim ].”

The Holcim quarry as it operates today will feature in the April-May issue of Q&M magazine.

Peter worked for Milburn at the quarry until he, and 28 other managers around the country, were made redundant in 1988. His son Scott also worked at Fraser Shingle and was there for 28 years. He is now a senior manager at Winstone Aggregates, also at Fernhill.

Can you help with next project?

Peter says his next project is to tackle a 16×8 or 16×12 Hauraki single togged jaw crusher manufactured by A&G Price of Thames.

Peter’s father Jock built and operated two of these crushers in the early 1950s and 1960s; one was in a fixed plant and the other portable.

A&G Price is no longer in business and so if there is anyone amongst our readers who may have one in the retirement section of their quarry then Peter would appreciate a photograph so he can measure up and scale his model.

Please phone him on 06 877 1013.

The Kumbee redesign

Although never trained as an engineer, Peter is capable of drawing very professional plans (see photos) and had the reputation in his working days for redesigning bought machinery and making it more efficient.

Peter says he was lucky to have attended Dannevirke High School as a boarder, as the school had a reputation for an excellent engineering course. Peter also had a gift for technical drawing and says he owes much of his success to his engineering master.

“There were no computers in those days so you had to research things by looking though books and lots of overseas magazines.” Peter adds that he also had a lot of help from the late Bruce Webster from Websters Lime in Havelock North.

The original alluvial quarry used a Kumbee Hammermill, bought from Keith Neiderer and built into the Fraser Shingle plant.

“I thought the running costs were exceedingly high,” says Peter. “I did a lot of research into this crusher. I weighed the original liner plates brand new, then divided the weight by the costs, which became so much per kilogram.

“Then I weighed the worn liner plates and discovered that some of the plates were only 10 percent worn and had to be discarded.”

With this knowledge he set about designing a new set of liner plates using one-inch wear alloy plate that could be gas cut and drilled. The original plates were from Nihard material and could not be drilled.

Peter then fitted these plates to the hammermill and this proved his point. Also, the original plates could be fitted in only one position. His new plates could be fitted in any position, right or left, front to back, etc and be repositioned part worn in other positions of less wear.

Peter went to A&G Price in Thames with his drawings and asked them to manufacture the plates from Nihard material. Peter then went to Paul Tidmarsh, who remains a good mate to this day, and asked him to build him a modified hammermill from his drawings.

“I made my drawings available to any operator who wanted to convert to this new design, which could be done in three stages, two top quarters and complete bottom half.

“I suppose I could have patented my design, but I believed in our industry and at that time we were all looking at ways to cut costs.”

Peter calculates that his liner plates cut the running costs of the crusher by 86 percent and back in those days that was a lot of money.

The original Kumbee also used a five-disc rotor with the centre hammer held by a forked shank. Peter worked out that it didn’t need a forked shank and, by adding another disc, you could use all the same shanks. He also found that he could have the shanks’ profile cut from two-inch plate and, by fitting a Caterpillar track bush cut to a two-inch width and fitted, the ID was the same size as the pivot shaft. Peter then had the shanks hard surfaced. Another cost saving.

Worn hammers also found another handy use after Peter discovered his Maori employees used them as hangi (earth oven) stones, because once heated they held their heat, and didn’t split like traditional stone.

The ‘Fraser modified design’ is still being used throughout New Zealand, Australia, and South Africa. Peter estimates that Keith Neiderer had built about 650 Kumbee Hammermills and Paul Tidmarsh also manufactured them through his engineering division Tidco (now Rocktech) and branded them ‘Tammerjack’, but they were exactly the same crusher.

There’s a Kumbee still at use in the Winstone Aggregates plant at Fernhill, where Peter’s son works.

In his retirement

These days Peter enjoys lengthy times at his beach house playing snooker and making models. Although never trained as an engineer, Peter is capable of drawing very professional plans (in the main photo he is holding tech drawings dated June 1978 of his modified Kumbee Hammermill).

The Kumbee model with Tidco base

Peter has always been a hobbyist and a few years ago he got an inkling to make scale models of quarry plant and equipment that he used at Fraser Shingle.

Peter decided to build them in 1/10 scale and obtained his original plan of the Kumbee from Holcim. With his technical drawing skills, he says he had no trouble in drawing new plans in 1/10 scale.

For the main body of the model he used 1/8 Perspex. The breaker plates are all cast in resin after making a mould using RTV rubber.

The liner plates were made from 1/8 Perspex and bolted into place using BA bolts and nuts and washers that are all made to scale.

The rotor disc he turned on his home workshop lathe from various 1/8 Perspex, while the shaft was from made from brass complete with threaded locking nut as per the original drawings.

The hammers are made from various thicknesses of plastic strip and the shanks cast from resin.

The base for the models is the same as for the Barmac Rotopactor. He was fortunate to have a copy of the original plans from Tidco. The base was constructed from plastic sheet, the deck from mesh as used by plasterers, the hand rails and ladder from Plastruct plastic, strip and rod.

The conveyor has a vulcanised rubber belt. All the rollers are made from brass tube and are able to rotate. “A very labour-intensive job, believe me,” adds Peter.

The electric motor was made from a piece of one and a half inch plastic pipe with the fins added from plastic strip.

The fan cover is from the bottom end of a pill bottle with mesh from a piece of fly screen.

The bearings were made to scale with brass tube and cast in resin.

The Kew Ken jaw crusher model

Peter’s interest in the model 56 Kew Ken began back in 1965 when his father Jock took a truck to Andrews and Beaven in Christchurch, purchased a portable crushing plant and towed it back to Hastings (see photo). Later, at Fraser Shingle, Peter operated two portable model 56 crushers and a third one that was built into the plant.

Peter began making his 56 Kew Ken jaw crusher models by photocopying plans from the original Kew Ken Armstrong Whitworth manual on his daughter’s photocopier.

The dimension of the full-size machine is 720mm, with the man-frame made from 1/8 Perspex sheet with the swing and fixed jaw from plastic sheet. The red fly-wheel is made from a piece of 70mm plastic pipe.

The cast lettering on the fixed jaw, proved a challenge Peter says. The letters are made using plastic strip and glued down individually.

“When I got to the ‘S’ in ‘crusher’ I found I couldn’t bend the plastic strip without breaking it.” Peter Fraser was not going to be beaten, “so I took a piece of brass wire, made an ‘S’, then filed it flat on both sides”.

“Just to make sure it stuck, I glued it with super glue.”

Barmac MK11 Rotopactor

Peter Fraser is currently working on a Barmac MK11 Rotopactor model complete with Tidco stand.

A quarter segment of the crushing chamber will be removed so as to see the rotor in position. The 150 electric motor already on the model was made from drawings that were supplied by WEG Electric Motors of Matamata.


This article was first published in Contractor March 2018.

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