Now that I've started on this route, I guess I'd better finish it! So here is the second 'bonus' posting - but only because I didn't get to finish it all of in the first posting about bore cuts! In this article we'll have a look at the second of the bore cuts that you'll need to be able to demonstrate and use for the CS31, and quite likely for the CS30 too. That's CS30 as well, as opposed to CS32... just sayin'. That second bore cut is the vertical bore cut, and I feel that it's appropriate to let you know hat this one has the potential to be very dangerous, as you'll be cutting very close to the kickback zone and even with it. Be careful with this one. Find out more after the jump...
Why would we use a vertical bore cut? Easier to watch a demonstration than listen to an explanation, but I'll give it a go... Look at the image at the top of this page, you can see that the underside of this piece of timber is not touching the ground and yet there was not enough room to get the bar and chain under the timber, without the chain running into the ground. In this case, with the compression cut already made on the top of the timber, we needed to cut from under the timber, back up to meet the compression cut.
To get over this problem of a lack of space, we can bore into the timber and then cut downwards and out of the bottom, as there is enough space for the chain to pop out from under the timber without striking the ground.
The other thing that you can see from this image is just where the bar and chain are positioned - note that the cut will be started slightly behind the kickback zone, and not on it.
Ensure that the saw is running at full speed whilst you do this cut, it's actually safer, and also make sure the saw is sharp. But perhaps the best advice for this cut is keep your head out of the line of the bar. Start the cut and allow the saw to cut a little way in, before levelling the saw out and pushing through the timber completely. Now you can come out of the bottom of the timber, before cutting up to the compression cut (in this case).
Try to do this in one fluid movement, saw at full speed and head out of the way - it doesn't bear thinking about what would happen if you had kickback... Also, be confident with this cut and hold the saw securely and comfortably.
I will be revisiting bore cuts, especially as now that I've started to write about them, the more I can think of to tell you!