Monday, January 31, 2011

Chainsaw Rakers

Well I spent the better part of four hours on Saturday sharpening the chains on my two 36" bars, getting ready for Monday's trip to Sechelt. Normally it takes only a couple of hours to prepare for each cutting session.

This time took longer because in addition to sharpening, I had to file down the rakers. This is an extremely tedious procedure, but needs to be done every 3-4 sharpenings else the teeth cannot 'bite' into the wood when cutting. I use a Dremel drill to hog each raker down to close to where it should be, and then use a file and a raker guide to get it bang on. I don't like the Dremel for sharpening the teeth though, I can't control it as well as I can a file.

I use ripping chain for cutting slabs. The main difference between ripping and normal chainsaw chain is the angle of the teeth. Ripping chains are normally filed to between zero and ten degrees, while a typical chainsaw chain used for bucking firewood say, is filed to about 30 degrees.

When a chainsaw is ripping, ie cutting a slab, it is effectively cutting end grain for the whole cut. And the saw's throttle is kept wide open for the whole cut, which may last five or ten minutes. So milling is about the hardest use a chainsaw can be put to in wood!

And of course there are many different types of ripping chain. I use two types, the subject of this particular blog entry is a bit unusual, it has two types of teeth on it, regular cutting/clearing teeth, and scoring teeth that have no top on them, they just score the wood to make it easier for the regular teeth. It's kind of hard to see the difference in the picture below, check out the top view in this link for more details.  Ripping Chain

I like this chain for a couple of reasons, I find it cuts a bit more smoothly than a chain with all regular teeth, and it allows the motor to maintain higher RPMs while cutting.  On the downside I do find it a bit fussier (ie dulls more quickly) and perhaps a bit slower. Of course, how sharp a chain is is way more important than anything else.

The picture shows the angle of a regular tooth in green and a scoring tooth in red. If you put your protractor to the screen you will find that the scoring tooth raker has an angle of about 9 degrees whereas the regular tooth is about 6 degrees. The cutting tooth raker is bang on, but the scoring tooth raker may be a touch aggressive.

Of course the whole measuring system falls apart quite quickly if the teeth are not a consistent height. And there is an element of 'eyeballing' that comes into play in the camera angle and in drawing the lines. Not to mention that the bar the teeth are sitting on has a slight curve in it.

I'll talk a bit more about tooth height in a future entry. Consistent tooth height is critical for several reasons.

Friday, January 28, 2011

Philosophy of Transitions

I have continued with the chainsaw milling.  A rather large but badly weathered and cracked Douglas fir was the subject recently. A couple friends and I took off three pretty fat slabs before we got to the middle which was too badly rotten to use.  It was over 3' in diameter so I had to bust out the big mill again. Two of us could barely carry the resulting slabs to the van when we were done! My left shoulder was a wreck the next day. I'd like to flip it and take some off the other side.

In fact I plan to go with some friends up the Sunshine Coast next week one day and mill up an arbutus. And the forecast is for cloudy, but no rain. Fun!

And, for the very first, time, I actually sold a couple of slabs to a stranger. A lady who had seen me cutting up an alder and who I had given my email to came through and bought two. I don't think I am going to get rich on slab sales, but it may help pay for the gas money! I have somewhat mixed feelings about selling wood that I get for free at the beach, but I guess I will figure it out.

In a similar vein, I met the president of a local wood salvage company, and in fact delivered a bunch of slabs to them this week, for them to sell. The next day they contacted me and indicated they had a line on sixty (60!) trees that were coming down locally and would I be interested in milling some of them up? Wow!

When you cross the line from hobby to business, it can change things from fun to less fun and even drudgery. Or, it can turn something fun into something different than what you imagined, but still fun or even more fun. I'm liking the latter perspective. Let's run with it and see where it goes.

Thursday, January 20, 2011


There seems to be a listlessness that has settled over the atelier, a feeling that the gods of woodworking have settled against me for some, hopefully temporary, reason. I've started on a simple knick-knack shelf out of arbutus, but I just can't get pumped up over any projects right now.

As I struggle through this woodworking ennui, I have turned my attention to my chainsaws and to slabbing. 3" thick spalted maple slabs, old growth red cedar, and catalpa have all been milled.  Maple shown below.

I even went back and had another go at what I called before the 'death elm' since it nearly killed me to mill last time. This time though, a better set up of the log combined with a very carefully sharpened chain made all the difference! It actually buoyed my spirits somewhat. Note the steeper angle that the log is set at, this makes a big difference in the amount of pushing I need to do. This way gravity does most of the work!

I wasn't planning on cutting any more of this elm but I got a request to do it, so I went down one snowy morning and got one slab taken off in about 1/2 hour. One of those rare times that everything went nearly perfectly, even with the 60" bar. A lady wants this slab for a garden bench.