Gary Blum
Since this is my first post on WC, the first thing I would like to do is say how much I enjoy the discussions here. This chipbreaker 'thing' is a good opening to join in some.

If you can get a 35° BD single iron plane to handle any grain other than a 'with the grain' board, you've really got something there. My ideal plane would be a single iron, BD plane with an adjustable mouth. Easy pushing, great surface quality, no second iron to fiddle with, grind the iron about 30°, maybe around 40-42 degree bedding. Kinda sounds Japanese, huh? I even built a metal adjustable mouth mechanism that was adjustable front to back as well as up and down, so it would put extra pressure right at the mouth. Needless to say, it's hard to adjust the blade depth accurately when you're ' extra pressure adjustable mouth mechansim that sticks a littlle below the sole' thingy is in place. I can provide pictures if anyone wants to pursue that futher.

The 64,000 dollar question then is: why doesn't the tight mouh work to prevent teaarout. I guess I should keep this personal here and say ... it doesnt't work for me. And people who say it does always seem to combine it with some other condition like ' tight mouth along with a super sharp blade' or tight mouth combined with high angle' or tight mouth and uber tuned plane, or tight mouh and .0004 ( .002 divided by 5) shaving. It always gets put back in some mystical notion, where we want to believe that someone, somewhere can build something so fine as to defy the laws of physics.

In trying to answer that question, I just try to use my own experience. I have always used Stanley #62 block planes in my work. I have 4 old ones I have worn out on my shelf. They all have a crack at the corner of the mouth going back. I know from using them that I can set the mouth practically rigjht on top of the blade, and when I hit reversing grain, it's going to stop.When you hit reversing grain, you are in effect wedging that piece between the blade and mouth. A wedge has tremendous power. Steel is not as stiff as people think. Deflection can easily happen. The other thing happening, where the video is so helpful, is to see the wood lifting ahead of the cut. It's easy to see that some additional pressure right at the mouth would be helpful here.

I thiink that is why this chipbreaker discussion has such traction and interest. You can see the phycis happening. As a planemaker, I tried the really close chipbreaker setting a couple of years ago after reading the Kato papers. It was a revelation to me, but others read the same thing I did and came to the opposite conclusion that the thing had to be set to the 'ridiculous' distance of sub .008 to have any effect at all, and therefore was originally designed as a blade stiiffener. I was a little hesitant to admit that , as a planemaker, I had never tried setting the chipbreaker really close, but that's the truth. Now that I have seen others like David Charlesworth and Philly say the same thing, I don't feel so bad.

I admire David Weaver for pursiing this and sharing his experiences. Thanks to Bill for the video. I really do think, for a lot of people, seeing is believing. Warren and I were involved in the 'chipbreaker thread " on Woodnet a couple of years ago. While I think we had some excellent (ha) arguments, in the end , not only couldn't we convince anyone that chipbreakers were effective, we couldnn't even convince them that they were more than just 'blade stiffeners'.

Back to work. My job this afternoon is planing quartersawn white oak drawer sides for a bedroom set. 15 drawers. I always leave my sides proud of the front and back, so I can fit the front and back to the opening first, and then just plane down the sides till I reach the dovetails. The white oak is local burr oak. Very squirrly and many pin knots. My plane is set up so I can plane these with absolute confidence and no tearout. Thanks, Kato.

Kind Regards,
Gary Blum