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Seal of Approval

Changes and improvements made to the Denharco telescopic boom delimber have met with the approval of Ontario delimber owner Rene Henderson.

By Tony Kryzanowski

When equipment manufacturer Denharco says the new DT 3500 is the "new generation" of telescopic boom delimbers, you will not get an argument from Chapleau, Ontario delimber owner Rene Henderson. He recently traded in his DT 3000 series delimber on a DT 3500 and, in his view, the DT 3500 is a far superior machine. Even when it came time to slap down the extra money for the DT 3500, Henderson knew he was making a good investment decision, considering the extra features this delimber offered him. He reckoned that he could make that money back in less than a year, with improved equipment up time and fewer parts replacements. "I'm doing about the same amount of wood as with the old one," says Henderson, "but I have less down time. The old one had more down time because of all those adjustments with the rollers and cables. I don't have that problem with the new one. So I guess I do delimb more because of less down time." He says such features as a chain drive on the telescopic boom extension instead of a cable drive, adjustable rollers, bolted on instead of welded on knives, and extra steel reinforcement on weak spots make the comparison between the DT 3500 and its predecessor almost like night and day. "When you break a knife on the DT 3500, it takes about a half hour to make a change," he says. "To change the knives on the older model, I used to have to cut them off with the torch and weld them back on. It used to take half a day. There is a big difference." While these features have made the biggest impression on Henderson, Denharco lists up to 30 new or improved features on the DT 3500. Henderson, a 19year veteran of the forest industry, is very knowledgeable when it comes to equipment performance.

For the past two years, he has operated his own delimber as Henderson Wood Products, using a DT 3000 mounted on a John Deere 693 carrier. He is also a skilled feller buncher and skidder operator, often taking a turn on a John Deere 648GII skidder or John Deere 653E feller buncher working in the same cutblock, but owned by another contractor. Henderson and his operator delimb 35,000 cords annually consisting of a mix of spruce, jackpine and poplar in the nine to 10inch range for Weyerhaeuser in Chapleau. They work about 17 hours per day on cutblocks located within 100 kilometres of the community. The cost of replacing cables, cable motors, and welded on knives on his DT 3000 was frustrating. "I was looking for low maintenance on my new delimber because the one I had before was all cable," says Henderson. "The chain drive on the DT 3500 is way better. The winch cable on the cable system caused me a problem every 200 to 400 hours. When you break those cables, it's a lot of work to get it back together." It usually took two people just over an hour-when everything wasn't tangled up. If a cable happened to break while he was working the night shift, he was left waiting to conduct repairs until his operator arrived in the morning. "Last year was a big expense just for those cables," he says. "I went through $6,000 in cables just for my winch. This year, I plan to do a year with that chain. You are talking about $1,800 for that chain, so its much better in terms of costs." What he may have lost in smoother operation with the cable motor system, Henderson says he has gained with increased power using the chain drive system.

Henderson has also noticed much smoother boom movement with the adjustable rollers, and considerably less cracking due to metal fatigue. On the DT 3500, Denharco says all rollers on the carriage are adjustable, as are the main boom vertical rollers for better contact and reduced wear and tear. The adjustable inner boom vertical rollers are mounted on self-aligning bearings, which ensure constant contact between the inside and the main boom and inner boom. The inner boom horizontal rollers are fitted with suspension and, like the vertical rollers, are mounted on self-aligning bearings for better contact between the two booms. This also means significantly less wear and less risk of damage. In addition to bolted on knives that are much easier to maintain, Henderson has also discovered a vast improvement in the chain drive motor versus the cable drive motor.

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Rene Henderson of Henderson Wood Products at the controls of the Denharco DT 3500 delimber mounted on a John Deere 200 LC carrier. The new Denharco telescopic boom delimber received praise from Henderson for its chain drive, instead of a cable drive, and adjustable rollers.
equip_profile_1_2.jpg (15002 bytes)

Previously, it cost him $8,000 when his cable motor failed after 14 months of use, because he had to replace the entire motor. With the chain drive motor, he is able to repair the motor on his own, at a cost of only between $1,500 to $2,000. He has put about 1,700 hours on his new delimber in nine months. "The delimber itself is very good," says Henderson. "There is no problem with that." In terms of electronics, purchasers have the option of including the new Control Plus II measuring system for increased precision and easier maneuvering. Another option is the Diatronic diameter-monitoring device. Diatronic uses an electronic mechanism, the resolver, which precisely and regularly transmits the position of the delimbing arms when they are in contact with the stem.

These signals are then transmitted to the computer that translates them into real time as a diameter read-out. After shopping around for a carrier, Henderson opted once again for a John Deere because of the excellent parts and service support provided by Ontrac Equipment in Timmins and his own familiarity with the John Deere product. While the 230 high and wide series excavator is recommended with the Denharco DT 3500 delimber, it can also be mounted on the 200 LC model. This was the option chosen by Henderson, who indicated that price was a consideration at the time of purchase. Although he says the 200 LC has worked well with the delimber head, he would probably choose the larger 230 excavator if he were to do it over again. "I don't know if it would be better, but it is high and wide," he says. "It's a little bigger with everything, and high and wide would be better if you were always in the bush without roads." He says the new carrier is also a considerable improvement over his 693 John Deere carrier. The 200 LC provides him with more power, delivering 140 SAE net hp at 2,150 rpm. It is burning between 170 and 180 litres of fuel in 11 hours. The forestry specific excavator has a 600-litre fuel tank, as well as a forestry cab and extra lighting. "It's a more powerful engine and I'm burning the same amount of fuel, so that's good," says Henderson.

Cab comfort is excellent, he says, and the most telling feedback he has received is from his operator. "My operator says the seat is comfortable, the cab is air conditioned, and you can hardly hear the motor. It is quiet. Cabs in other machines we tried were very noisy." Operating the carrier has not been without its challenges, however. Henderson has the exact same undercarriage problem with the 200 LC as he experienced with the 693. "I was breaking tracks, pins, pads and bolts," says Henderson, and that same problem continues on his 200 LC model. He suspects that the slider rock guards are too low, causing them to cut his pads. "I have 1,400 hours on it now, and that's my second set of tracks," says Henderson. "The first ones lasted until five weeks ago, and now these ones have been working for five weeks and are in real ly bad shape because of the rock guards." He says that John Deere is aware of the problem and is working to rectify it. Over the past summer, the carrier and delimber worked during some extremely hot weather. Henderson says he noticed a significant improvement in the 200 LC's performance versus his old carrier in these severe conditions. With his older carrier, he would have to clean the rad every day with a compressor.

With the 200 LC, he cleans the rad screen daily and washes it down and blows the rad out once a week. "We were working in 35 degrees Celsius, and the operator didn't have to stop," he says. "The temperature reading was high on the gauge, but it never boiled." Other than the problem with the rock guards on the carrier undercarriage, Henderson is very pleased with the financial savings and quality production he achieves with his Denharco DT 3500 and John Deere 200 LC carrier combination.

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A John Deere 648GII skidder was working with the Denharco/Deere delimber/carrier combination in a recent logging operation. On the delimbing side, delimber owner Rene Henderson and his operator delimb 35,000 cords of spruce, jackpine and poplar a year for the Weyerhaeuser operation in Chapleau.


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This page last modified on Monday, November 03, 2003