Cap iron settings

[Nicholas Lawrence]

I just picked up a copy of Charles Hayward's 1955 "The complete book of woodwork" and it is interesting that he has a whole section on the "close" cap iron setting and how it is used to prevent tearout. It really is an interesting book. He has a starter tool kit, which includes a wooden jack plane, along with a metal smoother, right along side a discussion of the merits of a tablesaw.

Anyway, I thought some of you might be interested to know that at least in Britain, after the war, the use of the cap-iron had not been forgotten, and is described at some length in a book designed for hobbyists.

[Mel Fulks]

Big fan of his books here,too. I disagree on one point,would not describe his books as being for hobbyists. They were just written at a time when people had less money and were more rural. One of his books is all tools and help aids for dealing with keeping up a house ,stuff dealing with handling heating with coal or making things no longer used or now just cheaply bought made of plastic. He was also an editor of some kind of woodworking news letter and had a reputation for polite but firm rejection letters. The book I've used the most is the one on joints. It not only shows the ones you are looking for but warns and instructs on handling things like joints between straight and curved mouldings; things I've needed only occasionaly and would have made a mess of without referencing his clear writing and all business drawings. Enjoy!

[Warren Mickley]

Yes, people knew about the double iron, but when it did not work for them on first try they assumed that it didn't work for anyone. Amateurs thinking they were experts. Here is a response I got to double iron use on another forum in 2005. A British hobbyist:

"The verdict is pretty much "in" on chip breakers. Assume for the moment that smoothing require shavings below 1/100". Essentially, this shaving is too weak for its passage over the chip breaker to effect the action at the separation point (i.e. blade edge) of the shaving.

Chip breakers are simply a way of keep the blade (and consequently edge) held firmly, and they also help the shaving "clear" the plane.
Despite loads of books and "the old guys" telling you different, in some cases with diagrams :-) "

[Steve Voigt]

Hi Nick,
I'd be very curious to know more details of what Hayward said.

[lowell holmes]

This string is a bit confusing to me. Are we talking about woodies? If so, it makes sense.

However, the old Stanley planes all have cap irons, and they are not always set thin. I do, but not really tight.

All of my woodies have a single iron as do the bevel up planes, so the bevel up planes are not part of this discussion.

[Jim Koepke]

"Assume for the moment that smoothing require shavings below 1/100".

I have even gotten shavings well below 1/000" with a bevel up jack plane.

For me a shaving in the realm of 1/100" is what my jointers and jacks are set to when removing saw marks.

"Despite loads of books and "the old guys" telling you different, in some cases with diagrams :-) "

And videos taken with precision equipment...

Warren, we all owe you and others thanks for making modern users aware of the joys of a properly set chip breaker.

jtk

[Kees Heiden]

The "lost chipbreaker knowledge" thing is a little queer. I think it was all a matter of miscommunication. I am absolutely sure there were quite a lot of people who knew exactly how to use the thing to prevent tearout (even with smoother shavings), and actually used the technique in their daily work. But their wisdom sure didn't trickle down to the internet community! There was a similar discussion on the ukworkshop forum a little while ago, and plenty of people dismissed the "lost knowledge thing", saying they knew about it all the time. But when you search back in the archives of that same forum, you only find 2 or 3 rather unfamiliar names who actually tell how to use it. I think most others knew about it in theory (it was in all the old books, like the Hayward one), but didn't actually put it into practice. For most of us, the Kato video was the real trigger to finally understand the concept and start using it in real practice.

And like Warren writes above, in contrast to the few people who advocated the use of the chipbreaker to prevent tearout, there were countless voices who vehemently discarded it. I think that mostly has been an internet thing. What happened in professional workshops around the globe is something beyond my knowledge, I am afraid most had switched to plywood.

[Nicholas Lawrence]

In response to Steve, he calls it a "back iron."

"The distance of the back iron from the edge depends on the work to be done. For the jack plane which takes coarse shavings it might be about 1 1/2 mm (1/16 inch) or more. For the fore plane which takes fine shavings rather less. For the smoothing plane when set for cleaning up difficult wood with twisted grain it should be as close as it is possible to get it."

This is the brief summary in the section on "setting." He then has a much longer section dedicated to describing the "use of the back iron." I am not going to type it all out, it is much too long, with illustrations, but he does say "It [the back iron] is needed solely because of the tendency of some woods to tear out owing to the undulating grain leaving little depressions in the surface known as tears (pronounced 'tares') which look unsightly." He notes the "disadvantage" that the closely set iron is much harder to push, and recommends moving it back for medium or coarse work, and really only using the truly close settings for smoothing.

His recommended tool kit has both wooden (double iron) planes and metal planes, and he does not make any distinction between the two in the discussion of the "back iron."

I have heard the theory before that the cap iron was to stiffen thinner blades to work without chatter, but having used a wooden plane now I don't think I really buy that theory. Mine has a double iron, and both irons are massive. It is used with both irons of course, but the single iron is easily thick enough to do just fine without any worry over chatter.

[Jim Koepke]

(Edited for brevity.)
I have heard the theory before that the cap iron was to stiffen thinner blades to work without chatter, but having used a wooden plane now I don't think I really buy that theory. Mine has a double iron, and both irons are massive. It is used with both irons of course, but the single iron is easily thick enough to do just fine without any worry over chatter.

That comes from the patent information:

https://www.google.com/patents/US724...t-CqoQ6AEIFzAA

My object is to use Very thin steel plane-irons, and in so doing I nd that they are liable to buckle under the pressure of the cap, which causes them to chatter, and makes them otherwise imperfect; and my invention consists in the providing of an auxiliary point of contact between the cap and plane-iron, and at the point where the plane-irontends to buckle or rise from its bed or base, and thus have a pressure at that point in addition to that at the cutting-edge, which iirmly holds this thin plane-iron to its bed.

The full text seems to have a few errors. The OCR software may have been less than perfect or the data entry person was tired.

I have seen back irons on older planes that do not have the Bailey hump.

It may have been the only way to have a patent for something that was already in existence.

jtk

[Steve Voigt]

Nick,

Thanks for the additional info. Very interesting.

It is often difficult, in 20th (or 21st) century texts, to know if the author is speaking from experience or simply repeating what an earlier book said. For example, I saw a new article just the other day, in a British magazine, about how to flatten and thickness boards. The author repeated the familiar advice to first plane the whole surface diagonally in one direction, then in the other. Now, I don't think most people who regularly flatten boards by hand work this way; I certainly don't. I think it's bad advice that just gets repeated by people with little actual experience flattening by hand. In the case of this article, I know enough about the author to be fairly certain that this is the case.

I'm inclined to give Hayward the benefit of the doubt, but who knows. Nonetheless, I'll try to get a copy of that book.

[Warren Mickley]

A few responses to statements in this thread.

And like Warren writes above, in contrast to the few people who advocated the use of the chipbreaker to prevent tearout, there were countless voices who vehemently discarded it. I think that mostly has been an internet thing.

Woodworkers were denying that the capiron had an effect before the advent of the internet.

I'd be very curious to know more details of what Hayward said.

Charles Hayward advocated the use of a cap iron, but he certainly was not using a plane the way we are talking about here. He was talking plane scrape and sand as the procedure for a fine surface. If he knew how to use a plane in a sophisticated way, he wasn't sharing it with his readers. He wrote:

. The smoothing plane cutter is sharpened to as straight an edge as possible, and the plane is set fine with the back iron as close as possible. It is assumed that the wood is already true and requires only to be skimmed to remove marks or tears made by the trying or panel plane. The entire surface is gone over with the grain. In most woods, the tears will come out, though, admittedly, there are difficult woods. So much depends on the plane and the way it is set. The cabinet maker’s smoothing plane has a high pitch in which the action approaches that of scraping rather than cutting, and if this has the back iron set fine there are only a few woods which cannot be planed. (Remember on this score that the straighter the edge the more closely the back iron can be set.)

“In any case, however, the scraper must follow for all hardwoods. It is not only that it will remove any tears that may be left, but it will take out all marks left by the plane. This is a point that is easily overlooked. Then again, in some difficult woods the grain runs in streaks about 1/4 in. or 1/2 in. wide, and it is impossible to plane one with the grain without tearing up those adjoining. The scraper can be bent and used on a comparatively narrow area of the wood.

“Glasspapering follows, and a flat rubber (usually of cork) is essential. The purpose of glasspapering is only partly to smooth the surface; it has for its second object that of getting rid of marks left by the scraper. This cannot be done when the glasspaper is merely held in the hand. The pressure is uneven and is not great enough. Furthermore, all sharp edges and corners are liable to be dubbed over, giving a dull, unspirited appearance to the work.