Little confused..

[steven c newman]

Everyone talks about moving a frog forward to "close up" the mouth on a plane.

every plane I have, except the WR#4 V3 bedrock style, has a short "ramp" between the end of the frog, and the opening in the base.

IF I move the frog forward, I tend to move off the ramp. There just isn't ant support for the last little bit of iron. Might make for chatter that way?

IF I move the frog back to open things up fore heavy cuts, like on a jack plane, the ramp is forward of the frog. Tighten the lever cap screw, and it bows the iron a little bit. It would also change the angle the edge presents to the wood?


Most of the planes I use a lot, I try to keep the ramp and the edge of the frog in the same "plane", so that it feels like a part of the frog.

With the frog so far forward, would that be an excuse to buy those extra thick irons?

Just wondering....

[Bill Houghton]

Whatever excuse you need.

On bevel down planes, the bevel's not touching the little ramp anyway. Test yours out; if, at cutting depth, the iron above the bevel's not touching the ramp on the sole of the plane, or only very little, then moving the frog forward would make no never mind. If there is contact, you'll have to decide by test if it's significant.

[Jim Koepke]

The frog certainly shouldn't be back far enough to lift the blade.

On planes before type 9 one of my suggestions for opening the mouth if needed for the new thicker blades is to remove metal from the back of the mouth.

Most of my planes with the thicker blades now have a tighter mouth, but it will still pass a shaving thick enough for my purposes.

When moving the frog forward to close the mouth one's intention is usually to take thinner shavings. A sharp blade with a well set chip breaker taking a light cut
is not likely to chatter in most woods.

Having a few planes of the most used sizes set up with different blades and mouth openings keeps one from having to change these settings.

jtk

[Chris Griggs]

I find it best to keep the bed of the frog in line with the ramp of the mouth. The reason for closing the mouth is to control tearout. While this does work I find it preferable to leave the frog in line and use the chip-breaker to control tearout instead...its more effective than a tight mouth anyway....YMMV

[george wilson]

Chris is correct: Setting the chip breaker extremely close to the cutting edge is the best way to stop tearout. That was proven months ago by that Japanese video,and by David's advise about setting it just a few thou away from the cutting edge. There was NO mouth in front of those cutting edges,no mouth at all. Yet,when set extremely close to the cutting ACTION,tear out was eliminated.

For this to work though,you must file the chip breaker until it touches the blade snugly all the way across. Any little gaps,and the wood will shoot right under the chip breaker and jam it. Check the chip breaker side of your plane irons and hopefully they will be flat. If for any reason they are a little convex,the chip breaker will have to be filed to snugly fit the surface right at the cutting edge.

To solve any problems with original irons,just buy the un messed with thicker irons. They will be flat. Make sure there are no gaps at all under the tightened down chip breakers.

To set the chip breaker,jam the blade vertically,edge down against a piece of soft wood(do not force the edge INTO the wood). Bring the chip breaker down to the good,and tighten it against the blade. Unless the chip breaker manages to creep forward and go BEYOND the cutting edge,all will be well. Make sure that doesn't happen. It shouldn't with the new,thicker irons with their more robust chip breakers.

[Daniel Rode]

Chris is correct: Setting the chip breaker extremely close to the cutting edge is the best way to stop tearout.

I don't want to hijack the thread but how close is "extremely close"? I've set the chipbreaker about 1/32 from the edge on my #4. Is that about right?

[Chris Griggs]

More like a few thou to 1/100 from the edge, depending on how thick a cut you are taking. Its actually really easy to set is super close if you watch the reflection on the back of the blade. I basically set it so its as close as possible but still just barely showing a thin reflection and than just back it off a touch from there. You very quickly learn how thick a line of light you want to get consistent results. I don't know how to measure the distance, but I know what it looks like and I know how to tell in use if its too far or too close.

Google search "Setting a Cap Iron" and you will find Dave Weavers very well written article that he published on another forum.

Note: As George says this will not work if you do not have a very solid mate to the blade. You also need a reasonable polish on the leading edge of the breaker. When I'm tuning up a breaker I typically set a bevel gauge to 50-60 degrees, lift the breaker up to that angle and then just freehand polish the leading edge...on the curved olde style breakers you can choose to polish a flat or take a rounding stroke to maintain the original shape. I don't think it functionally makes a difference as long as you have a good mate on the underside and a clean smooth leading edge at an appropriate angle.

[Steve Voigt]

Chris is correct: Setting the chip breaker extremely close to the cutting edge is the best way to stop tearout. That was proven months ago by that Japanese video...

George, I don't want to start a fight, but that is NOT proved by the Kawai/Kato video.
The 3 traditional remedies for tearout are (1) high angle, (2) tight mouth, (3) chipbreaker. The video starts with a low-angle, mouthless, single iron plane; in other words, none of the three strategies are used. It then goes on to test ONE of those strategies (the chipbreaker). Not surprisingly, this traditional strategy works very well! But the other two methods weren't tested at all. To do so, they would have had to run additional tests, raising the angle and/or adding a mouth.So, all we can say about the video is that it proves that one traditional strategy works; it says nothing at all about the other two.
I agree that the chipbreaker strategy works great, and since I don't have a fancy high angle infill, I'm not in a position to test the other two strategies, so I'll remain agnostic on which strategy works best.
For me, the important thing about the video, and even more so about Dave's article, is that it shows that the chipbreaker doesn't do jack unless you set it really really close. Like a lot of woodworkers, I would just set it kinda sorta close, and was always disappointed by my results. After I read Dave's article and learned to set the breaker correctly, my results improved dramatically. So, it's not that the video/article showed one method was better than another; it's that they showed how to use one method correctly. That's my opinion, anyway.

[Daniel Rode]

Thanks Chris. I read The WoodCentral article. I never really, in detail, understood what the chip breaker did until now.