NZ TIMBER
What do you do when you can’t get the wood to the mill? Simple. Bring the mill to the wood.
Our quarterly focus on the New Zealand milling and processing sector goes mobile in this issue to see the latest developments with Mahoe portable sawmills. Developed in Kerikeri more than 30 years ago, these mills are ideal for use on woodlots where access is limited.
AND THAT’S LIKELY TO BE THE BEST OPTION FOR SOME farmers and woodlot owners around New Zealand in the future, as access and transport costs affect the economics of harvesting forests in very remote locations.
What better way to cut those trees into saleable, or just usable, wood than by employing the New Zealand-developed and manufactured Mahoe portable sawmills.
These robust Kerikeri-built mills have been used in woodlots and forests in New Zealand and around the world for more than 30 years and they’re as popular as ever.
But Mahoe might never have come about if not for a lucky find. Company principals, John and Ben Bergman never set out to be mill manufacturers. It just happened.
The Bergman family, originally from Wellington, had a house re-piling business and purchased a farm in the Bay or Islands where they found some old Kauri logs in the bush while pig hunting. They applied to the Forestry Department to salvage and mill it on site, sometimes travelling 1-to-2 hours on rough forestry tracks and later heli-logging to recover inaccessible logs
There were no portable sawmills on the market, let alone any that could be easily transported or broken down and flown to the inaccessible salvage kauri logs.
Although there was an old mill at the farm, which is still in use today, they had a small, portable twin-saw unit custom-built to mill the huge Kauri logs in the bush, which John then re-built over the following years, improving on the design as they toyed with the idea of producing their own one day.
The Bergman’s also had a cheese-making business, using milk
from the family dairy farm, and it was whilst Ben was giving a sawmilling demonstration to a group of Russians who had come to see the Mahoe Cheese Factory that things took an interesting turn. The Russians were so impressed with the portable sawmill, they ordered two on the spot and Mahoe Sawmills was born.
Today, Mahoe is a thriving business, exporting sawmills around the world, from our nearest neighbours in the Pacific and across the Tasman, to Canada and the United States, as well as Africa.
And the range has grown, with the two sawmill models – the Supermill and the smaller Minimax – recently being joined by the trailer-mounted Whoppa Choppa wood splitter that is proving to be another winner with both local and export customers.
“We’re very busy,” Ben told NZ Logger magazine when we dropped in to see Mahoe Sawmills in its modern factory on a corner of the farm, off Oromahoe Road, which gave the business its name. As if to underline that point, the big whiteboard on the wall in his office identifies the orders currently on hand. The board is full.
Ben concentrates on the sales and management of the business, assisted by John’s wife Stephanie, while John oversees the design and technical side.
Out in the production facility they employ six people to do the manufacturing of various components for the mills and wood splitters, with George Anderson, the foreman, in charge of final assembly.
The basic design of the original Mahoe sawmill hasn’t changed a great deal over the years. All Mahoe sawmills are a leveroperated twin-saw design, with a horizontal and a vertical blade that cut on the way down the log and return the cut board, producing a finished board with every pass. The Supermill and Minimax both a have cut-to-taper feature, which wasn’t necessary back in the Kauri log milling days but is a requirement now with most logs harvested today having some sort of taper.
John says: “Using the cut-to-taper I can line the mill up to the log and cut the second grade core wood out in a tapered board. With this method, I retrieve full length boards from both sides of the log.”
Mahoe sawmills have cross members on each end, a boom and a bow head that runs up and down with the saws. But each one is subtlety different, built to suit the customer and can vary in length and width. Typically, a Supermill measures 8.3m long and 3.5m wide and 2.5m high.
The original mill used in the Kauri recovery days was powered by a VW motor, and had inserted teeth blades to produce a maximum 12” x 8” cut.
Nowadays, the engine on the Supermill is a Kubota diesel, with Deutz powering the wood splitter and driving the Minimax is a fuel-injected Briggs & Stratton petrol engine. Mahoe also offers an electric option and, interestingly, all the African mills currently on order have gone down this route, using big 3-phase motors
In the beginning, much of the fabrication was out-sourced to local engineering shops, then mated to imported parts at the Mahoe factory on the final assembly line.
Apart from the engines, gearboxes (from Italy) and key
components, such as bearings, pulleys, chains etc, almost everything is made at the factory now, explains John’s son Laurence Bergaman, one of the production staff, on a brief conducted tour of the manufacturing process.
“We have two guys here doing welding full time; two guys who cut steel and drill holes full time; plus another who floats between various jobs and helps me with the assembly,” he says.
There are three different parts to the fabrication process to produce a Mahoe mill; the cross-members, the boom and the power head. Laurence says they usually build a run of five to maximise production efficiency, meaning the fabricators will cut five different sets of cross-members for the welders to make up. Then one of the fabricators will build the boom.
Then the power head is fixed in place, followed by a trip to the paint shop, and the final assembly can start.
Among the most difficult tasks in the assembly is ensuring the blades run perfectly. Setting it up in the factory is all well and good, but these mills spend their lifetime working and sometimes just sitting in harsh conditions, so they have to be made to stay true and accurate over a lifetime.
The work put in by the Mahoe team is focused on making sure that it will provide the perfect cut every time.
Laurence goes on to say: “The biggest issue is when people change the saw bearings.
“We use stoppers and if they wind it back properly, in theory it should be perfect or if they put the right shims back it should go back perfectly, but that doesn’t always happen.”
Mahoe Sawmills offers a back-up service with some customers choosing to bring their sawmills back to Kerikeri for an overhaul. Most sawmillers do their own maintenance like changing belts, wire rope bearings, rollers and scrapers but checking blade alignment and cutting patterns is more technical.
Fixed, large-scale sawmills are usually set up to produce boards from one type of wood, but the Mahoe is very versatile and, in theory any type of wood can be run through it, from softwoods such as Radiata Pine, to hardwoods like Eucalyptus. The blades will cut through knots and wandering grain without difficulty.
The blade size is 700mm and can cut a maximum of 12 inches in the old parlance, or 300mm x 200mm. There’s no computer, it’s all mechanically operated and governed.
Blade maintenance is minimal and just require regular sharpening. Weld-on tipped blades are usually sent away for re-tipping when they get worn but the optional inserted tooth blades can easily be replaced on site by the operator.
And because it is set up at the factory to be accurate, the cut is reckoned to be among the best of any portable sawmill produced anywhere in the world, thanks to the rigid mounting, the centrifugal force and torque.
There’s practically no finishing or edging required, either, because Mahoe produces a finished board ready for use.
The amount of wood that a Mahoe mill can cut depends on who is running it and what sort of wood is being cut. It will happily produce 12 cubic metres of Radiata Pine in a day, says Laurence, who spent time on the road with school friend Kerry Ashby (who also works for Mahoe) running one of their portable mills.
“We were cutting native and used to do at least 10 cubes a day and that was on one of these older style boxed (Minimax) mills,” he says.
Mahoe sawmills are designed and built with several safety features. Both the horizontal and vertical blades have riving knives so the operator is not working near the blades. The built-in timber return eliminates the task of removing the cut boards from the mill and, being lever-operated, leads to reduced physical effort at the end of a busy day milling.
When each Mahoe mill is completed, John Bergman puts them through a practical test run, cutting up pine to make the packaging for mills being exported.
Mahoe sawmills are built to last and it’s not uncommon to see 20-year-old models working hard in a paddock somewhere around New Zealand. In fact, on the drive into the Mahoe site was a well-used mill that has probably clocked up 20,000 hours in little more than ten years and is still going strong.
Who buys them? The larger Supermill tends to be purchased by those who do a lot of milling and is the model mostly sold to overseas customers, whilst the Minimax is often the choice of farmers, or arborists who want to cut logs that are too good to go into firewood or mulch.
Sitting outside the factory is one of the latest wood splitters that Mahoe introduced to the market in 2014.
Like the sawmills, the Whoppa Choppa wood splitter – there’s just one model – is a thoroughly good-looking piece of kit and is built to perform and last for ages. It is aimed at professional or semi-professional firewood suppliers or arborists wanting to establish a sideline.
Powered by a 42hp Kohler industrial diesel engine with the option of the Deutz 48hp diesel and fitted with a pair of powerful hydraulic pumps, the Whoppa Choppa has an 800mm wide main knife to make the first cut, along with either three or four cutters to produce smaller blocks of firewood logs from the one press
It has an in-feed elevator to bring rings from the ground onto the cutting table and the split firewood falls onto a conveyor for loading into a static pile or trailer. It can cut two cubic metres of firewood in less than 10 minutes.
After appearing at the National Fieldays at Mystery Creek, the Whoppa Choppa garnered considerable interest and orders started to flow from customers in New Zealand and Australia.
Looks like the Mahoe team might need to consider an extension to the factory.
NZL