Capiron pushing or breaking

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Corneel

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No idea what happened but the old thread seems to be gone. Anyway, at the end there were two discussion. One of them was, is the capiron effect because the capiron is pushing the shaving back into the wood and thus preventing it tearing further. Or is the capiron effect because it breaks the shaving before it is strong enough to tear further into the wood.

Well. During my experiments I made 0.2mm thick shavings with the capiron around 0.25 mm set back from the edge. These shavings looked very stiff and not much breakage was vissible. But it didn't create tearout, while a setting of about 1mm defenitely caused tearout in the same piece of wood.

I think something happens like in this picture with a capiron that has a steep frontbevel:

capironpushing.gif


When you look at the Kato video http://vimeo.com/41372857 you don't really see breakage of the shaving either. Just a shaving that is being pushed forward. I think that is the clue. As soon as the capiron takes effect the shaving changes into a stiff forward bending thing. With the capiron out of the way the shaving just curls up without any pressure from the capiron.
 
Well i watched the Kato video again. It's completely obvious. For example around 14:40. No breaking of the shaving to be seen. The shaving is bended forward.
 
Weird these crumbly shavings in that last picture, Andy. My shavings don´t look like that at all when the chipbreaker is in the right spot. Neither are kato´s shavings. Only when I setthe chipbreaker really too close to the edge I get accordion-like shavings that want to clog the throat. Maybe that's where chips breaking theory comes from?

With the chipbreaker in the sweet spot, the shavings are straight and strong. No sign of broken chips.
 
Hi

Fascinating video I've not seen before, thanks for pointing it out. It looks like the shavings are being compressed on the front face, causing them to curl. I wonder if the effect would be different if they had simulated the effect of the front of the mouth. I have always understood that moving the blade close to the front of the mouth helps with difficult timber. If the action is due to compression of the shaving then mouth position may not be a factor, so why bother with adjustable frogs!

Chris
 
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