As we discussed in the previous post, chainsaw milling is best done with the very biggest chainsaws like Stihl MS 880 and Husqvarna 3120 XP. In general, prefer saws with engines 90cc and larger.
But what if you do not have such a monster saw and are not keen to shell out $1000+ of hard-earned money just for a milling saw? Could you do some milling with the more normal-sized 45cc to 60cc saw that you are likely to own?
Saw power is important in milling, but it’s not everything: with the right technique and accessories, you can indeed mill smaller logs even with a 50cc or 60cc saw.
In this article, I will tell you how: I will share my top tips on how to chainsaw mill with a reasonably sized saw. These tips are specific to low-powered saws; you may also want to check my top chainsaw milling tips.
Let’s first understand the issue:
The main challenge in milling with a small chainsaw is low engine torque: a small engine will struggle to pull the chain through a long contact with wood.
In practice, lacking torque means that the cut is hard to control and the saw keeps stalling. Push hard and the saw will stall; push only a little and the chain will just burn the wood.
Another major hazard in milling with a small chainsaw is overloading your saw. Running the air-cooled engine of your chainsaw at high RPM, wide open throttle for a long time can raise the engine temperature to unhealthy levels, risking damage to your saw.
Fortunately, there are many things you can do to help you smaller saw perform in milling – this is what we’ll discuss next.
Tip 1: Settle to small logs
A really important (if boring) piece of advice: stick to small logs with small chainsaws.
Milling torque demand scales with log width, so to help your small saw cope with the load, keep the cut width short. A good rule of thumb is to only mill logs 6″ thinner than the length of the stock guide bar for your saw.
For a log size vs. CC table, see my previous post.
Tip 2: Ripping chain
The first thing to check on the saw is the chain. When milling with a small chainsaw, use a ripping chain with scoring teeth and a skip sequence.
A ripping chain runs easier and more stable in the cut thanks to a lower sharpening angle and special cutter sequences. A ripping chain is recommended for all chainsaw milling, but is particularly important with small saws.
Tip 3: Keep the chain sharp
When milling with a small chainsaw, keep the chain extra sharp all of the time.
While important in any milling, a sharp chain is vital with a small saw. With plenty of power, you can force a dull chain through the wood just by pushing very hard. A small saw, on the other hand, will stall if you try to force it, and milling virtually stops.
I recommend you carry a chain sharpener (preferably electric) with you on site and sharpen the chain every two cuts. Alternatively, you can prepare a batch of ripping chains off-site and just swap a fresh chain in between cuts.
Tip 4: Seesaw
Seesawing, i.e. swinging your saw back and forth, is not recommended in chainsaw milling in general. The reason is that it lowers the surface quality of the produced lumber by introducing oblique cut marks on the wood.
However, with a small saw (or a very big log) you might still want to seesaw. Seesawing shortens the chain contact with wood and helps the chain to run lighter.
Seesawing is not possible with all chainsaw milling attachments, but Alaskan Mills for example will let you swing the saw.
Tip 5: Go Narrow Kerf
If you are planning to mill with a small saw, opt for a model that comes with narrow kerf (NK) chain and bar.
Narrow kerf chains, also known as low-profile chains, make a thinner cut into the wood. This is particularly useful in milling, where the cutting effort scales directly with cut width.
Thanks to the thinner cut, narrow kerf chain take less torque to run and helps your small saw perform in milling.
Narrow kerf chains are available in pitches 1/4″, .325″ and 3/8″; they are differentiated from regular chain versions by designations Picco, Pixel, and low profile (LP).
Pro-tip: You can often also convert your regular-kerf .325″ or 3/8″ saw to narrow kerf by swapping the drive sprocket, bar and chain for NK versions. Conversion takes some understanding of saw mechanics, but allows for very attractive power/kerf combinations for bars up to 20″.
For more info on narrow kerf, see my earlier article.
Tip 6: Swap drive sprocket (Pro)
Swapping your original drive sprocket for a smaller one helps your saw cope with the heavy milling load. (The drive sprocket is the small chain wheel that runs the chain; it is on the right hand side of your saw powerhead.)
Just like with your bike, choosing a drive sprocket with fewer teeth will give you more chain force for the same engine torque. For example, going from a standard 7-tooth sprocket to 6-tooth will boost your chain force by almost +20%. You will lose some chain speed, but this is not as critical in milling.
Note that shifting down with the drive sprocket is often feasible only when converting the saw to a shorter pitch or to narrow kerf. The reason is that most 3/8″ and .404″ pitch saws already run the smallest available sprocket (7 tooth) as standard.
Tip 7: Watch the RPMs
When milling, try to use steady medium engine speeds and avoid high RPMs – particularly with a small and under-powered saw.
Ripping is easiest when you keep the saw engine RPM in the peak torque region. For small saws, this region falls between 6,000 and 9,000 rpm, with modern professional-oriented saws closer to 9,000 rpm and old saws or consumer saws closer to 6,000 rpm.
Tip 8: Max bar oil
To lower the frictional power draw on your saw, always max out your chain oil flow when milling.
Milling tends to dry the chain much more than cross-cutting. All too often you find the drive link fins totally dry when you lift the chain.
A dry chain wears down, heats up and robs useful power from the actual cutting process. Bad in general, but particularly bad when milling with a small saw which is struggling to begin with.
To fix this, set your chain oiler for the maximum flowrate.
Tip 9: More oil in gas
Another protective measure you should take when milling with a small chainsaw is to run the saw with a thicker, oil-richer gas mix.
The standard gas-oil mix ratio for chainsaws is 50:1 when using modern synthetic or semi-synthetic oils. This mix lubricates well enough in general use, but may not be enough under the extra-heavy milling load.
Recommended gas-oil mix ratios in milling are 40:1 and 32:1; some people even run 25:1. Thick mixes like these make your saw smoke more and foul faster, but protect the engine from seizing.
Just be sure to clean your engine regularly when using oil-rich mixtures.