Granberg Mark III Alaskan Chainsaw Mill

The perfect tool for opening up new markets and new opportunities

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By David A. Boyt

Looking at a huge white oak resting on the ground after a tornado, I felt a little like the Roy Scheider character in the movie Jaws, when he sees the shark for the first time, and says, “I think we need a bigger boat.” 

The tree’s owner wanted the log milled so that he could have furniture made from it, for sentimental reasons. Problem was, the log was nearly twice the diameter that my portable mill could handle, and too far away from any other logs to make it worthwhile for a logger to come in and salvage. There wasn’t much I could do. If I could just quarter the log lengthwise, it would be much more manageable. 

Which is when it hit me: A chainsaw mill just might do the trick. If you’re not familiar with them, chainsaw milling attachments convert a chainsaw to rip down the length of a log. They consist of a framework to hold the saw, plus a chain optimized for ripping. They’re used to cut lumber most other mills are unable to handle (too long, too short, too large, or too crooked). They are not, however, practical for production cutting, because they’re much slower than most circle or band mills.

Although I had known about them for some time, I’d never seriously considered investing in one until watching them in action at the 2003 Great Portable Sawmill Shootout. This seemed like the perfect opportunity. 

Matching components to requirements

Granberg International’s Alaska mill is one of the best-known chainsaw mills on the market. Located in California, Granberg has been building its Alaska chainsaw mill since 1961, gradually refining it to its present design. Available through a number of dealers and catalogs, the Alaska’s price is reasonable. Add to this the fact that I had met Granberg’s president, Erik Granberg, at the Shootout, and had a chance to see their mills in action, I felt confident in choosing the Granberg. 

Once my mind was made up to buy the mill, the next problem was the myriad of options and additional equipment. While most mills come complete, the Alaska mill is more of a kit – in which the user matches components to their requirements. So I had questions, such as: What’s a slabbing rail? Would I need a second oiler? How about an option to add a second chainsaw to the other end of a bar? A visit to the company Web site helped, but it still took a phone call to the Granberg office to get the information. 

The folks at Granberg were extremely helpful in guiding me through the options. Using the Alaska mill to quarter large logs was a workable plan, they agreed, and gave me a run-down on the parts and prices. Of note: Granberg also sells a Mini Mill – is a vertical milling attachment, which can be used to edge boards, or to square timbers, but is not designed for cutting boards. 

The basic Alaska mill itself is a framework that holds the chainsaw, allowing it to ride down a level surface to make a cut of the desired thickness. This, with a ripping chain is adequate for small logs, assuming you already have a suitable chainsaw.

 Quartering a 4-foot diameter log would require a powerful chainsaw (Granberg recommended at least 90cc), and a longer bar and chain. Granberg suggested a helper handle, which allows a second person to guide the tip of the bar. They also suggested an oiler for the tip to improve lubrication, and a slabbing bracket to hold the rails for the first cut (more on that later). Armed with this information, I placed my order for the mill, 48-inch bar, ripping chain, oiler, helper handle, and slabbing attachment. I already had the chainsaw, a Husqvarna .372. 

Out of the box

About a week later, the box arrived – an entire sawmill (minus the chainsaw, of course) in a box that I could easily pick up myself. The instructions consisted of a break-apart drawing of the basic mill, with each part numbered. Although it looked complicated, there were only nine steps in the written instructions. In an hour and a half, I had assembled the mill itself; anyone who can assemble a sing set from the plans should have no problem. Once assembled, the milling attachment forms a strong rigid framework, light enough for one person to carry. 

Next, there was the matter of building a slabbing rail – the mill rides on this rail when making the first cut. The slabbing rail is basically a pair of straight 2 x 4-inch boards (not included), at least 2 feet longer than the longest log you intend to cut. Granberg’s slabbing brackets consist of a pair of 16-inch long aluminum extrusions with slots for the bolts that hold them to the 2 x 4 slabbing rails. This allows the sawyer to adjust the distance between the rails to accommodate different size logs, and to compensate for taper. 

To get a feel for the machine, I chose to use the mill with a standard 24-inch bar for the first several logs; this would give a maximum cutting length of 18 inches. The first order of business was to turn the log for the opening cut. Then I attached the slabbing rail, using the double-headed “scaffold” nails provided by Granberg with slabbing kit. According to the instructions, the slabbing rail should be level across both ends, to avoid making a twisted cut. A “U” bolt at each end holds the saw at the desired height on a vertical post. Changing the height requires loosening four nuts, sliding the saw bracket on the calibrated scale at each end, then re-tightening the nuts. With a little practice, a sawyer should be able to set the height in less than a minute. 

Finally ready to cut, I fired up the chainsaw. Although Granberg recommends a special ripping chain, I was curious to see how a conventional chain would cut. Just before the saw cut through the log, however, the slab pinched the bar. Remembering something in the instructions about wedges, I drove in several along the length of the slab to support it, then easily finished the cut. Total time: about 6 minutes. Considering the amount of sawdust created by the ¼-inch kerf, and the limited power of the saw, 6 minutes was not unreasonable, but I still wondered how anyone could build a house this way. No complaints about the quality of the cut, though – it was about as smooth as anything I’ve cut with a band mill. 

For subsequent cuts, the saw bracket rides on the flat surface of the wood, which means that any bumps or twist will be transferred to the rest of the boards. As long as each previous cut was flat, the mill continued to produce flat, straight cuts.

With practice, the setup and sawing went more quickly. There were, however, several problems: The vibration had caused several nuts to loosen, and two had come off, and were lost in the pile of sawdust. An aluminum casting broke when the supporting nut and bolt parted ways under the vibration. Lock washers should have been provided for all nuts. Granberg quickly replaced the broken bracket at no cost.

A more substantial log

After cutting several logs, it was time to add the 48-inch bar, helper handle and oiler. Assembly instructions consisted of a break-away drawing of the part, but no written instructions.  A little common sense is required to put it together. Still a drawing with a few instructions would have saved some time.

The helper handle is a definite requirement for working with a long bar. While this makes the mill a two-person operation, it provides better control. Granberg, incorporated a chain tensioner in the handle, making it possible to tighten the chain even if the saw’s adjusting bolt is not accessible. Granberg recommends an additional bracket to support the longer bar, as well as a supplemental oiler, since the chainsaw was not designed to adequately lubricate a bar of that length. Fitting the chain to the bar was another problem: Anyone who has untangled a normal chain can only begin to imagine the frustration of untangling the chain for a 48-inch bar! The oiler and cube made it look like the chainsaw was receiving an IV drip.

With the machine finally assembled, it was time to tackle a more substantial log. A friend had a big (40-inch diameter x 8-feet long) oak log that he wanted milled. The idea would be to rip the log into two manageable-sized pieces, then finish them on my band mill, a Timber Harvester 30HT25. After topping off the fuel and oil in the saw and switching to a ripping chain, we were ready to begin. 

With the slabbing board secured to the log and the height adjusted to split the log down the center, we put the blade to the wood. It took about 15 minutes for the saw to chew through the log. About 7 feet into the cut, the saw died – we were out of fuel. After refueling, we finished up the cut.

 The final task was to edge the logs. We ran two parallel chalk lines about 6 inches in from each edge of the log, put the shorter bar on the chainsaw, and trimmed it, cutting with the bar in a vertical position. We finally had two halves that were small enough to put on the bandsaw mill.

 The milling itself was uneventful, except that the mill’s hydraulic log turner is designed to handle round or square logs. It took a bit of wrestling to get the half-logs into position for cutting. For our 2-1/2 hours of work we cut more than 450 board feet of lumber out of that one log.  

Again, with practice, subsequent logs cut more quickly. For example it took less than 15 minutes to square up a 33-inch diameter ash log to a manageable size (my mill has a 24-inch throat). Much of that time involved setting up the slabbing rail and adjusting the cutting depth. 

Opening new markets

Although I’ve had limited experience with the mill as I write this, I have reached a few conclusions: The Alaska chainsaw is an effective way to cut large (well, what we call “large” in this part of the country) logs to a size that a band mill can handle – in my case, 26 inches at the large end of the log. Due to the amount of time required to make a cut, this system pays off for only high grade logs and for slabbing specialty woods, such as walnut crotches and burls. Small-scale sawyers who cut dimension lumber should consider either selling the larger logs to a commercial mill, or setting up a traveling blade circle mill.

 There’s little doubt that the chainsaw mill will open up new markets and new opportunities for my small operation. Several area sawyers have already asked me to bring it to their sites to cut special pieces of walnut and cherry that are too large, too crooked or too short for their mills to handle. The mill will also allow me to offer extra wide slabs to custom woodworkers, give the flexibility to handle jobs too small to justify bringing in a band mill, and to work in urban areas without moving logs and tearing up lawns. An important aspect of my operation lies in the ability to take jobs that other sawyers turn down, and to provide unique services. The chainsaw mill fits perfectly into this plan.

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