I promised some more info about my log building course experience. There has been some delay due to some discussions with the course owner about intellectual property. That is another discussion on its own, but for now we have to come to terms about what I may ‘reveal’ or how I may approach this so that his proprietary techniques are not fully revealed. My own view is that personal instruction is still the way to master these techniques and knowing what to do it will not take away from his opportunities in teaching you how to do it.
Having said that, this blog only grazes the surface anyway and is merely meant to show what is possible and to pique the interest or to possibly close some gaps for some others who may have had other instruction. By no means will you become an expert after reading this and by no means should you assume you know what you are doing just from reading this.
This part explores chainsaw techniques useful to the trade but also good general chainsaw skills to have.
Logs can be worked with an axe or an adze but the use of chainsaws presents its own advantages and its own skills for producing things out of logs other than firewood. Even with these tools, this should be considered a labour intensive hand craft.
The context here is log building and several cutting techniques are used repeatedly in log building but could equally be applied to other building methods or other uses (perhaps some of these techniques might be familiar to chainsaw artists).
Note that the use of a chainsaw is inherently dangerous. Appropriate safety precautions, gear ( chaps, steel capped boots, helmet, face mask ) and training should be sought before putting saw to wood. If you are unfamiliar with the safe methods of chainsaw use, please enroll in a local chainsaw safety course.
The first technique is cutting a simple flat sided notch . This is simply two angled cuts in the log which meet partway through the log, cutting a wedge out of the wood. This cut is familiar to log fellers though, of course they are not following a line. Cutting the sides of the notch to a fixed angle or to a premarked line and having the two cuts meet exactly is a skill.
The notch is used in log building in at least two different places. A rough notch is cut in each end of the log when positioning the log on the wall before final scribing and the notch cut is also useful when initially cutting out the wood for the final scribed notch ( this notch precisely fits the saddle of the log below it – more on this later). In log building, usually you are following a line when cutting.
In the rough notch, the objective is to cut as closely to the line as possible, leaving some of the line on. ( Here the line represents a ‘rough’ scribe used to drop the log closer to the one below it, as well as preventing it from rolling – preserving the angle is the most important factor ). When using this cut to begin an actual scribed notch, the cut stays as close to the line as possible but never going over it as here the line to which you are cutting is an actual scribe line to perfectly fit the log below it.
When the same technique is applied to an actual scribed notch it’s cut much more carefully – you can’t cut over the lines here, otherwise you end up with a gap between the logs. In addition only 1/2 of the notch is cut from each side, so a total of 4 cuts is used just to define the outer edges. These scribe lines should be near a straight line, since they are scribed to the saddle below them, and the saddle is sanded to a flat surface before scribing. If the scribe is such that the V-lines would not meet, then multiple cuts are made so that the wood can be knocked out within the scribe lines.
Carving. The carving cut allows a hollow to be made on the otherwise straight side of a notch. This technique involved starting the cut on the edge of a notch and cutting only the width of the chain. With no wood on one side of the chain bar, the bar can be turned in the cut and a curved cut left behind. It’s important that a semi-chiselled chain be used. A full chisel chain tends to want to cut straight as soon as it enters the wood, whereas as semi-chisel allows some wandering, which can be used to advantage.
In the carving cut, the speed is kept fairly high ( not screaming fast, however), and only the tip of the bar is doing the cutting. The chainsaw is steadied and guided against your leg and the chainsaw is merely lowered down, using the weight of the saw to set the speed of the cut.
Brushing. The brushing technique is used to precisily remove small amounts of material using the tip of the chain. The bar always runs at right angles to the wood being removed. This can be used to create coves, required to fit one log over another, and to precisiely remove wood in grooves, notches. The chainsaw runs at medium speed and the tip of the bar brushed back and forth across the wood being removed in small slow movements. This cut can leave very smooth surfaces. In fact it is operating like a small planer. Care must be taken of course not to touch any of the wood in the dangerous kickback zone of the bar, ie the top 1/2 of the tip. Keeping the bar at right angles to the wood also ensures that the saw stays put and doesn’t run across the log or up the sides of a notch cut.
Saddle cuts. The generally accepted best practice for joining logs at the corners is using notches placed across two cuts which called saddles. These are curved cuts on either side of the log on a pitched angle ( the precise angle is unknown and not important and will vary with each log). The two cuts make the log at this location look like a saddle and hence the name. The curved cut is made with the chainsaw – yes, the chainsaw can be used to cut curves just like a bandsaw. The curves of course are not severe and can easily be made with a regular 18” bar. The curves still end leaving a flat surface along the length of the log. This is useful when scribing the notches which sits on this saddle since that now ends up being nearly a straight line for easier cutting with a chainsaw.
The saddles are best cut ‘wrong handed’. ie: the trigger is operated by the left hand and the right hand is on top of the bar pulling the saw into the cut. The saddles are marked out with a top, bottom and two side V marks and the bar is first lined up to create the angle required to just hit inside of the top and bottom cut. The cut is started on the inside of the end mark and ends just inside the end mark at the other end. This way and rough edges left by the chainsaw can be cleaned up with other chainsaw techniques or with a grinder and still leave room to flare the saddle out to the lines.
The chainsaw is running full speed on this cut because it is cutting a wide rip cut whereas the chains are usually designed for cross cuts. The chainsaw moves slowly and should always be running exactly at right angles to the log. The saw chain will want to move the saw towards the operator but the weight of the saw will want to the move the saw down into the cut. When correctly executed, the saw seems to float in the cut because of the two counteracting forces. It is a very nice feeling and the saw feels very light in the cut. This leaves the right hand to guide the saw throught he cut.
This cut is as complicated as it sounds but it can be mastered. The most difficult part of the cut is to maintain the right angle and to create a nice even flare into and out of the cut. The first few cuts usually need a lot of doctoring with the grinder but after several cuts, cutting, cleaningup and sanding this cut in could be accomplished in less than 15 minutes.
Long brushing. A technique which I call long brushing is also used whenever a large amount of material is to be removed over a flat surface. This is similar to the brushing technique but instead of only the tip of the bar being used, the entire bar is used like a small planer. A refinement of this technique is to tilt the bar to the right as you sweep left so that only the edges of the chain teeth touch the wood. With reasonable high speed and a slow sweep, a very fine plane like cut can be taken, leaving only minor saw marks. ENsure that your chain is well sharpened.
Planing. The chainsaw can be used like a planer by using the side of the chainsaw teeth. Tip the chainsaw to the right, with the engine up and hold the bar flat across the surface to be ‘planed’. Tilt the bottom of the bar up so you are sweeping the surface with the top of the bar if you are planing from right to left. Tilt the top of the bar up and cut with the bottom teeth if you are planing from left to right. This leaves an even finer finish than long brushing and is useful for flat surfaces such as a flat bottom sill, planing the curves of the saddle or possibly even a slab or a benchtop for applications other than log building.
The techniques are all ways in which you can use the chainsaw for precise and smooth cuts and most of these techniques are well known and applicable to other than log building..
-- If you can't joint it, bead it!