Thanks for sharing, appreciated. Real info, real angles, real experience - gives some facts. Observations are how we know and we can't easily see a chain cutting in the wood. Super slow motion and instant freeze flash photography do give some observations but finding such info difficult. The physical realities of cutting chain has so many interactive dynamics that much knowledge has been simplified into rules of thumb, traditions and myth. THINKING ABOUT THE CUTTING ACTION AND SOME *EFFECTS* OF THE DEPTH GAUGE. Wood strikes the leading edge *forcing it to rock back on its heel,* cutting forces cause the tooth to leave the guide bar and take a bite. In coming back down I imagine the pulling forces through the chain cause _the top of the depth gauge to take on a mirror role of the heel and rivet_ *but as a single point of rotation* _(i.e. it is not the same as the leading edge, heel and its rivet combining to make it leave the guide bar.)_ BUT, if this rotation/pivot back to the guide bar, takes place on a flat depth gauge then I imagine it will be bumpy (think rolling a bolt with a hex head verses rolling a bolt with a round head) If the rotation is on a curved depth gauge then it should be smoother. So _I imagine_ the depth gauge being smoothly curved to give a smoother cutting experience. This will also save energy, wear and tear on parts and reduce hand circulation issues??? This is a pretty easy one to test. Do some cuts with fairly long flat depth gauges, round them and compare the 'chatter'. Everything is fairly easily controlled. I might do it. Vibration is a core safety issue in chainsaw use and I’ve always had poor circulation in my fingers. _I imagine_ there to be a lot of research into what causes chainsaw vibration because of hand circulation issues. Might do a bit of research into it. Cheers sincerely d
Ah, thinking about it a little more it seems the depth gauge being rounded will allow it to gradually roll and take the leading edge out the wood, making for a smoother cut. Not really a mirror of the heel but benefiting from the rounding. It's a lot of fun thinking about this stuff.
It's cool that *something* motivates you to post more videos. I think I can add here that the depth gauges do not normally have to determine the depth of cut, i.e. the thickness of the chips. This is particularly true of the greater cutting length. Their height only determines the *maximum* of the depth of cut. In addition the depth of cut or chip thickness can be greater than the difference between the height of the tooth and the depth gauge. This is because the depth gauges can dig into the wood, especially soft wood. A simple formula can be derived for chip thickness: depth-of-cut = (feed-velocity / cutting-velocity) * chain-pitch * tooth-spacing tooth-spacing is 8 for a standard chain, 12 for (full) skip. I think a more correct definition of the angle of attack would be: The angle of attack is the angle at which the cutting edge enters the wood. Nothing revealing for me, but the video below also contains confirmation of my assumptions about the sharpening of the cutters in the factory. These guys know what they are talking about. There will probably be even more videos. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-P0TQHFDFBxg.html
Actually, I should ask what was the thickness of the chips in both cases and was there a difference? If the thickness was less than 0.65 mm, then probably the difference in depth gauges height didn't matter much.
I watched that video and really hope he does more with those guys. They made some good points, especially about balancing the whole setup, it's easy to push to far and go backwards. I didn't measure chips when I tried, so I can't answer that. Best I can say there is I don't know. I'm still trying to figure out why chainging the depth gauge high didn't have the effect I thought it would. It's a 79cc, 6+HP saw with a 60DL chain. It should have reacted differently. I can only put it down to the way I shape the depth gauge allowing it to be pulled into the wood more efficiently. If we take the 0.65 vs the soft setting it's a big change in the angle (3.3 to 4.9). If it's critical to cutting, it should change something. You'll see a few more videos soon. I bought 6 different 3/8, 058, 72DL chains. 2 full and 4 semi and the 4 semi chisels all have a different cutter profile. I want to show how bad some of the factory grinds are and to see how the difference semi shapes change their cutting performance. Suprisingly, the worst of the new grinds come from a big name, the cheapest chain did a decent job.
@@SawChainTheories If I am not mistaken in the formula in my previous comment you would have to have a really high feed velocity (i.e. push really hard) to approach the maximum chip thickness determined by the difference in tooth and depth gauges heights. I assumed that the piece being machined was about 30 cm thick. Did I get that much wrong? Obviously a major simplification also due to the circular shape of the cut piece: feed-velocity = 3 cm/s = 0.03 m/s cutting-velocity = 15 m/s chain pitch = 3/8'' = 3/8 * 25.4 mm = 9.525 mm = 0.009525 m tooth-spacing = 8 depth-of-cut = (0.03 m/s / 15 m/s) * 0.009525 m * 8 = 0.0001524 m = 0.1524 mm You can use more close to the true values that you have observed in practice...
