Back To The Future: Bore Cuts (1)

This is a bit of a bonus posting, as I've got 10 minutes free to quickly add an article! And so, in this post we're going to go back to the future and look at bore cuts. Why 'back to the future'? Well, bore cuts currently form part of the CS30 chainsaw maintenance course, but are heavily used during the CS31 (and CS32) felling courses; because of this, it'll be useful to both groups of people - those undertaking CS30 and those doing CS31. I'll try to put together a short video of completing a bore cut as it's much easier to see it, rather than describe it, but for now you'll have to make do with text! Find out more after the jump...

There are two types of bore cut: horizontal and vertical. The image at the top of the screen shows the horizontal bore cut, and is used a lot in conjunction with felling techniques (rear-weighted, forward weighted, medium and large fell). The vertical bore cut is used to cross-cut timber, especially where there is not enough room under the timber to physically fit the bar and chain, and you want to cut upwards; although there is enough room to bring the chain out of the bottom of the timber without it hitting the ground.

The Horizontal Bore Cut

The horizontal bore cut is slightly safer than the vertical bore cut, but is perhaps more difficult to get all the levels correct. You will need to keep the saw level from the tip of the bar back to the rear handle, as well as keeping it flat from side-to-side.

This is easily achieved by positioning your hands correctly on the handle; remembering that your thumb on the left hand must remain around the handle (see the Bad Habits: Thumbs Up! post). First off, getting it level from side-to-side is just a matter of moving your left hand right around the handle as far as practicable, this will automatically put the saw in the correct position. Easy!

Now for getting the saw level front-to-back. Many operators continue to hold their right hand in the same position (finger on the throttle) and twist their wrists to account for using the saw on its side. However, this often results in the rear handle being held higher than the tip of the bar and so the saw is not level. Instead, as you twist the saw on to its side, getting it ready for the horizontal cut, allow the rear handle to move around in your right hand; you should find that you can operate the throttle with your thumb.

Stand so that the underside of the nose of the bar will be introduced into the timber, then cut down to about where the nose sprocket rivets are. At this point, keep the nose of the bar in the same place and swing the rear handle around so that the saw is now directly pointing into the timber. Now push. Not too hard, and keep the saw running at full power until you have bored through to the required depth.

Allow the chain to stop in the bore cut before pulling it out of the wood (it might be wise to flick the chain brake on too at this point). Now, we are going to need to refine this a little bit but that'll be what the video is for... I just need to shoot it first ;0)

I reckon my 10 minutes is definitely up, and I'll leave vertical bore cuts for another post...

Bad Habits: Part Four:

This next bad habit is not one that I see too often, but every now and then it finds its way back into the students mode of working. It is, of course, the knees down approach to cutting timber. So what's wrong with this? After all, it looks to be a nice stable and comfortable position to be cutting in, and the operator is down next to the wood, rather than bending over it (another favourite). Whilst these things may indeed be true, it's not really the safest thing to do, so how should you be cutting timber that's on the floor, just like in the picture?

Find out more after the jump...

Well, the problem with putting both knees down on the floor to cut the wood is one of unsafe working practices, and it simply boils down to the fact that the operator cannot move out of the way quickly enough should anything happen.

Instead of putting both knees down, the best thing to do is to adopt a sort of crouching position, although if you need to put one knee down for stability or comfort, then that is acceptable.

If you're a bit sceptical about this, try it for yourself! Kneel down with both knees on the floor, then try to stand up, or move sideways... now just crouch down so that neither knee is on the floor. Now stand up; you should find it a lot easier to get yourself out of the way. [Probably best not to do this if you have poor knees!]

Of course, for logging timber then it's better to use a saw-horse or similar, to allow you to stand up and cut, but that's not option if you're dealing with a tree that you've just felled and you're cross-cutting the stem.

In the next of the 'Bad Habits' series, we'll have a look at cutting using the top of the bar...

Teaching Tension & Compression

I recently had a student that found it difficult to fully grasp the concept of tension and compression wood. This student understood that if a piece of timber was only held at one end, then the compression wood was underneath, and that's where the first cut would be made; but when it was balanced at either end, they just couldn't see it. What I needed was a way to help this student understand where the cut should be made - this gained particular significance as I'd been told that they had failed a previous attempt at CS30 on demonstrating knowledge of tension and compression! Find out my solution after the jump...

After we had been down the woodyard, practicing the crosscutting, I have to admit that I thought we'd got it sussed. But we hadn't - my fault really and now I needed to come up with something that would help this student. Walking back, I was running various ideas through my head when I had a moment of inspiration.

I needed something quick, simple and easy to understand. Perhaps something this student could take away with them to practice with.

The result can be seen in the picture at the top of this post - click on it to get it full size (A4). Here's how it works...

• Cut out around the edge of the rectangles, and then fold in half as it shows.


• After folding it, glue it together just to hold the halves in place.


• The elliptical pads represent where the wood is held up - so if you place the single pad touching on a table, or whatever, with the other end free, you'll see that the free end sags down (because there's nothing holding it up). Holding it this way, you can also see that the letter 'T' (tension) is uppermost and the number '2' (second cut) is showing. This tells you that the compression wood, which you would cut into first, is on the underside of the timber.


• Now turn the paper over and balance the two pads at either end across your hands. You can now see that the letter 'C' (compression) is on top, and the number '1' (first cut) is showing. This tells you that the first cut to make is the compression wood on top.

It's easier to do, than to explain ;-)

Anyway, if it's of use to anyone, then please feel free to download it and give it a go. If you're a trainer, then feel free to use it. As for my student? They passed with flying colours.

CS30 Assessment Schedule: 'Small Print'

As well as listing what you are expected to achieve in the assessment, there's also the obligatory small print, and you might just be interested in one particular snippet. Find out more after the jump...

The five recordings below cover the general introduction to the schedule, safe practices, the complaints and appeal process, objectives (learning outcomes) and assessment / site requirements. The bit you may be really interested in appears in the safe practice bit - but more of that when we come to it..

Introduction to the assessment schedule:

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The safe practice section from the assessment schedule lists what might be an important point, and one that might just put your mind at rest for the assessment... item 13 tells you that you can refer to the chainsaw operators manual and/or appropriate training publications.

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If, for some reason, you are not happy with the assessment, NPTC do have a formal procedure for dealing with complaints and appeals. This information is shown in the schedule; or you can listen to it here...

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The learning outcomes, or objectives, of the assessment (and therefore also of any training you receive to help you achieve success in your CS30 assessment) are listed in this next recording.

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Finally, the assessment and site requirements are also listed in the 'small' print of the schedule, before we get to the real nitty-gritty of the assessment activities and criteria.

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In the next post we'll start our journey through these assessment activities and criteria, taking a quick look at each one as we go.