A chip breaker reminder

[Larry Williams]

Somewhere further than the thickness of the fattest chip from the edge, maybe by a factor of two. On a coarser cut, you're probably already trying to do most of your work across or downgrain.

If the plane is too hard to push in a heavy cut, then it's too close. If it's not controlling tearout, and you can't plane downgrain for an entire stroke, then it's too far away. Warren mentioned several times that it's something you just do with experience (by feel). I don't know how far away my fore plane is set, but my jointer is fairly close, maybe 3 times as far from the edge as the smoother, maybe twice. You'll find something that's comfortable pretty quickly, something that you don't have to change in use.

First of all, none of this was lost to anyone who's done more than follow recent Internet influenced fads. Secondly the Kato video has been around for a long time. I'm not sure when Steve Elliot first put it on his web site but we used information from it in a WIA presentation more than four years ago and I know it was up for a couple years before that. Now people are holding up Kato's research saying from one side of their mouth, "See, this validates what a few people have claimed." From the other side of their mouth they're saying, "I get different results." Which is it? Either a cap iron starts to have some influence at .008" from the edge and good results at .004" from the edge like Kato found or his results are bunk. Which is it? Maybe I missed the thaumaturgy section?

No where is anyone talking about what's actually happening to the wood or what's influencing its behavior. How is that behavior different when using a double iron than when using a steeper pitch. No one is talking about the extra work of maintaining what is essentially two cutting edges for each plane iron. I tuned up a lot of old double iron planes over the years and used them in my work. No one is going to convince me that the wear I've seen and experienced on cap irons is anything but normal.

I'm amused at the thought of putting and identical camber on a fore plane's cap iron and iron then adjusting them for each depth of cut used. Are people trying to do woodworking with their planes or are they just tinkering with tools? Maybe everyone is still thinking every plane is a smooth plane?

I was up this same blind alley years ago. I decided I wanted the tools for woodworking and know where I ended up. Last time I watched a stampede up this blind alley I deleted about 3/4 of the woodworking forum bookmarks I had. I guess I wasn't thorough enough.

[Sean Richards]

Planecraft, Chapter 4, Adjustment of the Plane (1972 impression underwritten by Woodcraft):

Chart on cap iron working positions:

"For rough work: 1/32" [.794mm]
"For finish work: 1/64" [.397mm]
"For hard woods with irregular grain: as close as you can get it to the cutting edge"

If one is following the progression then maybe 1/128th? This is .198mm I believe - a glint or basically as close as you can get it.

Somebody check my metric conversions.

NOTHING NEW UNDER THE SUN.

Hi Charlie, I posted pretty much the same comment back in May

Not sure any of this is "lost" or "forgotten" knowledge. I was taught to set the cap-iron on a smoother at about 1/64" for general fine finishing and as close as possible (hair-thickness was the term used) for difficult timber. This same information (and discussion on the action of the cap-iron) is readily available in any number of woodworking books - at least in those written by authors who have had formal trade training.

Unbelievable the amount of discussion this topic has generated. But then again I was taught the little I know about cabinet-making in the pre-Internet days so what would I know

[Sean Richards]

First of all, none of this was lost to anyone who's done more than follow recent Internet influenced fads. Secondly the Kato video has been around for a long time. I'm not sure when Steve Elliot first put it on his web site but we used information from it in a WIA presentation more than four years ago and I know it was up for a couple years before that. Now people are holding up Kato's research saying from one side of their mouth, "See, this validates what a few people have claimed." From the other side of their mouth they're saying, "I get different results." Which is it? Either a cap iron starts to have some influence at .008" from the edge and good results at .004" from the edge like Kato found or his results are bunk. Which is it? Maybe I missed the thaumaturgy section?

No where is anyone talking about what's actually happening to the wood or what's influencing its behavior. How is that behavior different when using a double iron than when using a steeper pitch. No one is talking about the extra work of maintaining what is essentially two cutting edges for each plane iron. I tuned up a lot of old double iron planes over the years and used them in my work. No one is going to convince me that the wear I've seen and experienced on cap irons is anything but normal.

I'm amused at the thought of putting and identical camber on a fore plane's cap iron and iron then adjusting them for each depth of cut used. Are people trying to do woodworking with their planes or are they just tinkering with tools? Maybe everyone is still thinking every plane is a smooth plane?

I was up this same blind alley years ago. I decided I wanted the tools for woodworking and know where I ended up. Last time I watched a stampede up this blind alley I deleted about 3/4 of the woodworking forum bookmarks I had. I guess I wasn't thorough enough.

Good post - Thank you!

[David Weaver]

Last time I watched a stampede up this blind alley I deleted about 3/4 of the woodworking forum bookmarks I had. I guess I wasn't thorough enough.

Larry, your eyes must be pretty bad if you can't tell the difference in finish between a 55 degree plane and a common pitch plane using a cap iron. The finish is remarkably brighter by the latter because it is cutting at a lower angle. The fact that the cap iron keeps the chip from getting levered up doesn't change that it's being cut by a 45 degree iron. The only way to get a duller finish doing that is to set the iron too close and compress the fibers in the wood. That (the fact that the cut angle is low while the tearout is controlled) is exactly the reason it's different. You can compare the kato pictures to the LV pictures (which were single iron) and see the difference, but more practically, you can see it easily just by using the two planes on difficult wood, or any wood.

As far as the rest of your comments, lets go through them:
* there is no keeping two irons sharp. In almost a year now I haven't seen any reason to recondition the edge of any cap iron. I think if you check warrens comments, you'll find that he said the same thing except over a period of decades. There is no fiddling with the second iron. Once it's working, it's used as is - not touched again.
* there is no cambering of cap irons. Even if there were a reason to do it in principle, there'd be no reason to do it in practice. But in principle, a cambered iron is making the rankest cut right at the middle, where the cap iron is a greater distance to the edge, and a lighter cut further from the center where the cap iron is closer. No cambering. I'm not even sure why you brought this up, other than to create a false dilemma. Nobody has advocated such a thing, and certainly nobody who is actually dimensioning wood with their planes.

As far as your sentiment, either you have picked a conclusion, or to paraphrase warren, when I see a lot of the assertions about surface quality or difficulty of use, I have to conclude that you just really never learned to use a double iron properly.

The precise reason this came up is because for those of us who don't use power planers, it's practical and it makes a very inexpensive plane (a stanley bailey type) perform better than a bevel down single iron plane in both softwoods and figured hardwoods. And it makes flattening and smoothing faster (there is no skewing planes on quartered faces, etc). I'm not sure why anyone needs a better reason than that.

The only real practical problem I've found with it at all is that a lot of late 19th early 20th century wooden planes were not made properly. But then again, their single iron counterparts from the same era were not very good, either. Both rely on a craftsman who can resolve any problems they have from quick manufacture. Improperly executing something doesn't negate the usefulness of properly executed designs, and still the cheapest planes most can find in functional condition are not affected by that problem.

[Kees Heiden]

Dear Larry Williams,

First, nobody claims that this is anything new. We do know that some loud voices on the Internet, yours among them, claimed that the chipbreaker is a rather useless appendage in a plane. Because normal woodwork training is almost extinct these days, and because the old books are not very accessible for everyone, the internet is a valuable information source for us. The new presentation of the Kato video was lucklily very convincing and made us clear that your kind of information about chipbreakers is in fact faulty.

The chipbreaker works. It works very well. It isn't too difficult, but applying the knowledge to different situations means a learning curve. Nothing wrong with that, learning is fun. Wear on the chipbreaker isn't something I have witnessed yet, but I hear from Warren that he hasn't seen it happen in his planes yet.

The exact distance from the edge isn't so important, there is range of usefull settings. It just needs to be a lot closer then I thought in the past.

And when are you going to correct the errors in the article about chipbreakers on your website?

Have a nice new year, and I wish you all the luck with making and selling your steeply pitched wooden planes.

[Sean Richards]

In almost a year now I haven't seen any reason to recondition the edge of any cap iron

David how many actual hours of use would that be over the course of a year?

[george wilson]

I don't see what all the controversy is about whether cap irons work. The video in question proves it does. How can that be denied with the closeup pictures of the chip breaker action? I am a convert myself. I used to wonder how those single knife Japanese wood surfacers worked without grain tear out. They shove the wood through a stationary blade. Now it has been explained. Good enough. Several years ago I could have bought one of those Japanese surfacers cheap,but I did not,because I was afraid of grain tearout. Now I understand how they work. I still don't think I'd want one,though since they don't plane very wide wood,and I am concerned about wear on a single blade,HSS or not. I have been advised that those planers were designed for a special purpose: Planing soft wood posts for Japanese houses,so there are no thickness planer chop marks.

[Sean Richards]

Dear Larry Williams,

First, nobody claims that this is anything new. We do know that some loud voices on the Internet, yours among them, claimed that the chipbreaker is a rather useless appendage in a plane. Because normal woodwork training is almost extinct these days, and because the old books are not very accessible for everyone, the internet is a valuable information source for us. The new presentation of the Kato video was lucklily very convincing and made us clear that your kind of information about chipbreakers is in fact faulty.

The chipbreaker works. It works very well. It isn't too difficult, but applying the knowledge to different situations means a learning curve. Nothing wrong with that, learning is fun. Wear on the chipbreaker isn't something I have witnessed yet, but I hear from Warren that he hasn't seen it happen in his planes yet.

The exact distance from the edge isn't so important, there is range of usefull settings. It just needs to be a lot closer then I thought in the past.

And when are you going to correct the errors in the article about chipbreakers on your website?

Have a nice new year, and I wish you all the luck with making and selling your steeply pitched wooden planes.

Rush of blood to the head ?

[David Weaver]

David how many actual hours of use would that be over the course of a year?

Of planing? I have no idea. The respective plane has probably been sharpened about 30 times, maybe 40. As in sharpened and used until it was dull, not sharpened and used 10 strokes and then sharpened again.

But why would you rely on my comment when Warren has used his tools to make a living (and has for 40 years) and clearly states that he doesn't remember working on or rehoning a cap iron?

[Sean Richards]

Of planing? I have no idea. The respective plane has probably been sharpened about 30 times, maybe 40. As in sharpened and used until it was dull, not sharpened and used 10 strokes and then sharpened again.

But why would you rely on my comment when Warren has used his tools to make a living (and has for 40 years) and clearly states that he doesn't remember working on or rehoning a cap iron?

Warren is not posting here so I can't ask him ...

[Johnny Kleso]

I always looked at cap irons from what it would take to manufacture one back in the 1800s..
Making a screw was a big deal back then threads most times where filed on, let alone tapping the hole it went into..
Thats why most times tapped holes where in a brass insert..

I always seen cap irons in these two views.
Either they help with leaving a good finish or they are to make the blade thinner to make sharpening easier, since most folks didn't had a bench grinder back in those days.. I always favored the finish argument side of the coin due to the amount of extra work and cost in making a cap iron back when they first arrived on the scene..

[george wilson]

Personally,I don't really see how the chip breaker would actually make the blade stiffer. I'd think it would make the blade more liable to flex. The cap iron doesn't touch the blade on many planes,except at the top,and down at the edge of the chip breaker. There is air space much of the way. Plus,I have seen blades bent hollow by the pull of the chip breaker's screw,making the blade not lie flat on the incline. And,the wedge not being powerful enough to pull it down flat. How can this be helpful in making a blade stiffer?

From most posts in this long thread,it seems that reasonable people are now convinced that the chip breaker works. Even Swartz. But,there are the die hards who can never be convinced that they ever held an incorrect view on anything.

[Matt Radtke]

Somewhere further than the thickness of the fattest chip from the edge, maybe by a factor of two. On a coarser cut, you're probably already trying to do most of your work across or downgrain.

If the plane is too hard to push in a heavy cut, then it's too close. If it's not controlling tearout, and you can't plane downgrain for an entire stroke, then it's too far away. Warren mentioned several times that it's something you just do with experience (by feel). I don't know how far away my fore plane is set, but my jointer is fairly close, maybe 3 times as far from the edge as the smoother, maybe twice. You'll find something that's comfortable pretty quickly, something that you don't have to change in use.

Yeah, I guess fores and jacks don't really apply, I was more thinking out loud. My line of thought was my jointers are set relatively coarse compared to a smoother. If I back I breaker off "appropriately," might it be too far back to get the magic curling? Pure speculation on my part, of course. I haven't had time to putz with them yet.

[Larry Williams]

Larry, your eyes must be pretty bad if you can't tell the difference in finish between a 55 degree plane and a common pitch plane using a cap iron. The finish is remarkably brighter by the latter because it is cutting at a lower angle. The fact that the cap iron keeps the chip from getting levered up doesn't change that it's being cut by a 45 degree iron. The only way to get a duller finish doing that is to set the iron too close and compress the fibers in the wood. That (the fact that the cut angle is low while the tearout is controlled) is exactly the reason it's different. You can compare the kato pictures to the LV pictures (which were single iron) and see the difference, but more practically, you can see it easily just by using the two planes on difficult wood, or any wood....

David,

I went down this road about 20 years ago. Shortly after the "oldtools" mailing list began a guy from Montreal named Paul Pedersen and I exchanged a lot of e-mail over weeks, maybe a month or two, about improving the performance of smooth planes. We tried a lot of things and started out looking for the shiny surface you seem to prefer. We pretty quickly came to realize that the most cleanly cut surfaces were dull looking with no shine. A shiny surface is a reflective surface. Here's a micro-photo of red maple, what do you see here that would be reflective?



An increase in cutting angle or a very closely set cap iron increases the visco-elastic deflection ahead of the cutting edge. This deflection actually holds wood fibers in place by compression as the fibers are being severed which reduces tear-out. Both an increasing cutting angle and the very closely set cap iron do the same thing but, when you increase deflection, you also increase fiber spring-back after the fibers are severed. The difference between the steeper cutting angle and the closely set cap iron is that the double iron doesn't come with an increase in clearance angle behind the cutting edge. The shine you're obviously looking for comes from the wood being burnished by the back of the cutting edge as it springs back. Want more shine?? Just increase the bevel angle of your plane iron by about five degrees to further reduce the clearance angle. The problem is that you're running into the same issues of low angle planes with obtuse bevels, you're shortening your edge life and increasing your maintenance time.

If you and Kees want burnished surfaces it's fine with me. I don't care but I do know that burnished surfaces are hard to get uniform and can cause problems with finishes or adhesives.

[David Weaver]

Larry, I get a shiny surface with a 15 degree clearance angle or a 20 degree clearance angle, the same as 10 degrees. The surface does not get better with a 20 degree clearance angle as I wear the iron (which decreases the clearance angle) I think you've made a logical argument that you buy, but I don't know that I do unless I get one of these new trick powder metallurgy irons and find out that if I increase clearance to 25 degrees that all of the sudden I'll get a dull surface.

What do you think will happen? By your assertion, I should see a duller surface. I don't think I will.

It is very easy to get a uniform polished surface, unless you do something to scuff it after you've finish planed it.

At any rate, whatever looks better, that's what I'll take. I've never had any trouble with glue surfaces either. How many smoothed surfaces are you gluing together?