May 2000 - Logging and Sawmilling Journal

The new log loader/forwarder that's moving huge payloads of wood these days in the yard of the Grant Forest Products oriented strand board mill in Englehart, Ontario is a unique hybrid machine. It owes its components, and design, just as much to Dave Edwards and his maintenance crew at the mill as it does to the Koehring and Caterpillar equipment that went into it. The Grant operation has three vintage Koehrings doing 24/7 work-operating 24 hours a day, seven days a week.

These units handle approximately 3,000 tonnes of wood every day, moving logs from the yard to the slasher. In addition to moving wood in the yard, the machines also have the task of unloading any short wood- eight foot or 14 foot bolts-that come in on the logging trucks. These Koehrings, purchased new in 1989, now have more than 85,000 hours on their clocks. "They were getting old," says Edwards, mobile equipment supervisor at the Grant operation. "We had to do something with them ."

Normally, heavy equipment reaches the point where it costs more to keep than it would to purchase new machines. Originally, it was generally thought that the mill would get about seven years out of these Koehring loader/forwarders-but they're now at eleven and counting. The reason: Edwards was able to get out in the field over the years and buy parts, sometimes in the form of complete units, for a fraction of the price of what they'd normally go for. The units, working as forwarders in the bush, were being phased out with the move to more environmentally acceptable logging and softer footprint forestry equipment.

The rebuilding of the Koehring unit using a Cat 330 loader was truly a team effort of the maintenance crew at Grant Forest Products (bottom). Dave Edwards, mobile equipment supervisor, says every member of the crew is a good mechanic, but they all have their specialty areas, such as welding, hydraulics and electrical, where each brought particular strengths to the project.

"Over the years, I've probably purchased all the old Koehrings available in Ontario for used parts to keep them going," Edwards explains. In addition to "cannibalizing" machines, the Grant operation has also set up a number of ongoing relationships with suppliers who have helped them meet their parts needs. "We've generally beefed up the units so they will do the work we want them to do. But time is running out. There are no units left to be bought for parts. We're in the situation where we have to start doing something with the units we have ."

Operators and management at the Grant operation are big fans of the Koehring 440 models. The machine has the capability of handling a 50ton payload of wood and unloading with a butt 'n top grapple. "We find them very versatile because we have to move different lengths of wood and it can do it all, whether it's tree length, 14 foot or eight foot ." Edwards notes that they looked at some of the new equipment, machines that could handle 20 tonnes or so. "In the larger poplar that we have, though, they would not last. They could not handle the job because the wood is so heavy and because of its length ." Even if they were able to find a source of additional parts for the Koehrings, Edwards says it was becoming clear that it was time to move on to new technology. "It was getting beyond the point of no return," he says. "In terms of fuel economy and hydraulic capabilities, we were looking at some limitations on the existing machines. Equipment technology has advanced a great deal since 1989 when these units were built ."

The second Koehring unit is now in the Grant shop for its refit.

Their solution was to re-power and reengineer their existing Koehring units in-house, and the first one to roll off the Grant Forest Products maintenance department production line hit the yard in January- and it is performing quite nicely. Edwards and his mechanics really did not expect anything but that, though. They have had enough experience with the machine, and the Grant operation, to know exactly what is required-or demanded may be the better way to put it-by the operation. They basically stripped down the first K3 Koehring "to nothing", explains Edwards, and built from the ground up.

All of the engineering, Edwards proudly says, was done in-house, which makes perfect sense. "We have a huge amount of experience with the 440 and know our operation. The group has just been fantastic on this project ." Every member of the maintenance crew is a good mechanic, Edwards says, but they all have their specialties. Several were particularly good welders, while other team members were strong on hydraulics and electrical. Rebuilds of the major components-planetaries, transmissions, and differentials-were done in the Grant rebuild shop. Nothing major went back into the machine without being re-bearinged or re-sealed.

An important point to note is the rebuild was done in addition to the regular workload of the eight mechanics. On an ongoing basis, they have 40 pieces of equipment to maintain in the mill yard. Edwards is quick to point out they did have some very valuable outside assistance, however. The concept of repowering and reengineering the Koehrings, he says, was pioneered by an associate-and now good friend-Hugh Hambley, equipment maintenance manager at the St. Anne Nackawic pulp mill in New Brunswick. Hambley is an old hand at this, having reworked four Koehring units for St. Anne.

Edwards visited Hambley's operation to get a firsthand idea of how they did the repowering there and received advice as the project proceeded. A crucial point in the rebuild was that the unit's pedestal had to match the Cat 330 log loader upper structure exactly. They had a very rough drawing of the bolt circle on the 330 structure and, working with supplier DeRose Manufacturing of Guelph, Ontario, they built the pedestal to exactly match the Cat 330 structure. "The most nerve wracking time," recalls Edwards, "was when the 330 arrived and we lifted it off the float to bolt it on ." His worst nightmare was that the bolt holes would not match. "But when the machine went on," he says, "all forty bolts went on by finger. It was quite a feat ."

Edwards praised Caterpillar, the local dealer Toromont in Timmins and Toromont's forestry engineer Victor Casaletto for getting behind the project "110 per cent". In terms of completing the custom unit, the Cat 330 met their needs, coming straight from the factory with a logging boom, heavy duty car body, custom riser package and all the forestry guarding. "We had to do very little to make it what we needed. We just had to build one cat walk and install our own swivel ." And the unit is getting high marks, so far. Edwards notes that in the past they had tried to give the old Koehrings more power and speed through beefing up the hydraulics, but he calls the Cat 330's performance "unbelievable" in those areas. "You cannot make this machine smoke no matter how hard you push it or how big a load you've got or how hard you push on the drives. They have really done their homework on this unit ."

Rebuilds of the major components- planetaries, transmissions, and differentials-were done in the Grant rebuild shop. Nothing major went back into the machine without being re-bearinged or re-sealed.

Overall, Edwards says there is little he will do different with the Koehring/ Cat/Grant hybrid unit #2 that is now in the shop for a refit. They will likely move the box that the loader is positioned on forward to give the unit better balance. "The first one is a bit heavy on the rear," says Edwards. There is very little tweaking to be done. "The steering cylinders on the first unit don't have as much stroke as I'd like, and they don't turn as sharp as I'd like. When you're coming along our rows in the main log yard and want to turn to get on the main road, you have to take your time. It doesn't turn as sharp as the old ones ."

There are also some very minor changes. With the engine up top, they're going to try and put a port in the swivel so the machine can be fueled from the ground. He expects the project to go a bit faster the second time around-the first rebuild, which again was done almost completely in-house, started in January and was completed in December, 1999. "We can probably do the next one in 20 per cent less time. We ran into more damage in the chassis than we anticipated, so we had to spend more time on that and we'll be able to plan it out better. It was a good learning curve ."

Edwards says there were a few issues that had to be discussed with suppliers before they went out for quotes on machine #2, but ideally they'd like all three machines to be as close to identical as possible in terms of components. "It makes life a lot easier for the operators and maintenance side of things ."

The Grant OSB operation looks for 99.5 per cent availability from yard equipment when the slasher is running. Even though they were working with older Koehring iron, yard staff were able to slightly exceed that.

Main Page

Hybrid Iron

Grant Forest Products' Englehart mill is taking its vintage Koehring units and rebuilding them using a Cat 330 log loader upper structure.

By Paul MacDonald

Rebuilds of the major components- planetaries, transmissions, and differentials-were done in the Grant rebuild shop. Nothing major went back into the machine without being re-bearinged or re-sealed.