rfeeser
Member
Registered: 05/28/04
Posts: 20891
Loc: Central NC
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CedarSlayer said:
When the blade is skewed to hog out wood, and the mouth is opened about as wide as it should ever be opened and the wood is being removed well, you may see the chip breaker crack chips. This does not seem to help the 'finish' at all
It won't help the finish any if the wood and tuning of the plane are such that they produce a good finish regardless of whether or not there's a chipbreaker. But often in wood that is not well-behaved and likes to tear out I've found the chipbreaker really does help the finish.
But as you said, it also depends on how the plane is tuned. It really is more obvious how the chipbreaker helps if the plane is poorly tuned.
I'm not sure whether you meant to imply that planes shouldn't be set very coarse to hog out wood if used properly. I believe that is a perfectly valid use of planes. I do not do everything with one shaving thickness. First, I use a progression of planes often that are already tuned to take progressively thinner shavings, starting with very coarse ones with a scrub plane or medium thick ones with a jack plane. And I also withdraw the blade a little while working with each single plane, so that my shavings at the end are thinner than they were when I started with that plane. But initially I take shavings as coarse as I reasonably can to get the work done quickly. I don't just start with 0.004" shavings and plane and plane and plane.
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Cheers,
Bob
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rfeeser
Member
Registered: 05/28/04
Posts: 20891
Loc: Central NC
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evenfall said:
I will however add that most of the shavings I have seen in 40+ years of seeing them, have not ever struck me as anything I would describe as a broke chip. Thin and curly.
First place, if the shavings are thin, I agree a chipbreaker's breaking action is not helpful. The shavings are already too thin and weak to need that.
But the curly part--that's all a chipbreaker is said to do. The object isn't to break the chips apart into chips, but to bend them slightly, which is accomplished by making a lot of tiny breaks in the convex side of the chip. That curls the chip and weakens the fibers that could otherwise be levered up out of the wood in front of the blade. Look at some of the books that show diagrams of how the chipbreaker "ideally" weakens the chip to reduce tearout.
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Cheers,
Bob
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rfeeser
Member
Registered: 05/28/04
Posts: 20891
Loc: Central NC
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EricU said:
One thing I've noticed about many of the old planes I've bought is that more of them had the sides of blades rounded than not. And it was clearly intentional and nicely done. My LN scrub plane came with a blade that was very rounded, so maybe that's what these planes were used for.
I've never heard of people doing this routinely, and it made me wonder what else people knew about woodworking that I don't. A lot, I'm sure.
Aside from my joint-making planes like shoulder planes and rabbet planes, etc., nearly all of my planes have either cambered blades (most) or rounded corners (fewer). All my jointer planes (long bench planes) have cambered blades except for the one with the jointing fence bolted on.
The cambering and rounding on my smoother blades is not there for the same reason the scrub plane blade is cambered at all, and the camber is only about 0.003" higher in the center.
Heavy cambers like those used in scrub planes and often in jacks are to allow much thicker chips (not shavings) to be taken, to hog of wood fast. Very slight cambers like those used in smoothers are there to finesse the edges of successive overlapping parallel strokes, avoiding what are usually called "plane tracks." And the camber used on a jointer plane is there for an entirely different reason; it makes it very easy to square an edge using a specific technique that requires that camber.
So now, for one thing, you've heard of someone doing that routinely, if you count cambering along with rounding the edges, which for finer work is often considered a different way of accomplishing the same thing.
And all cambering and rounding of corners is not the same and doesn't accomplish the same thing.
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Cheers,
Bob
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CedarSlayer
Killer of aromatic wood
Registered: 07/06/06
Posts: 2167
Loc: College Station, TX
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rfeeser said:
CedarSlayer said:
When the blade is skewed to hog out wood, and the mouth is opened about as wide as it should ever be opened and the wood is being removed well, you may see the chip breaker crack chips. This does not seem to help the 'finish' at all
It won't help the finish any if the wood and tuning of the plane are such that they produce a good finish regardless of whether or not there's a chipbreaker. But often in wood that is not well-behaved and likes to tear out I've found the chipbreaker really does help the finish.
But as you said, it also depends on how the plane is tuned. It really is more obvious how the chipbreaker helps if the plane is poorly tuned.
I'm not sure whether you meant to imply that planes shouldn't be set very coarse to hog out wood if used properly. I believe that is a perfectly valid use of planes. I do not do everything with one shaving thickness. First, I use a progression of planes often that are already tuned to take progressively thinner shavings, starting with very coarse ones with a scrub plane or medium thick ones with a jack plane. And I also withdraw the blade a little while working with each single plane, so that my shavings at the end are thinner than they were when I started with that plane. But initially I take shavings as coarse as I reasonably can to get the work done quickly. I don't just start with 0.004" shavings and plane and plane and plane.
I am with you on this, Bob. That is why I love a good jack plane. I am of the opinion that if a wood worker is going to have only six planes, the should get a LA block, a smoother, a rabbet, and three jacks.
I like to harvest wood left on the curb. This is ecologically win-win to me. I'm not a wealthy man, so I scrounge wood where I can get it.
A lot of those logs are too much or too irregular for the bandsaw. Resawing in order to get a nice face, is sometimes a poor option as well. So I often split them first. If I didn't use a draw knife, scrub and jack to hog wood off, there are nice hunks of wood that I would have to abandon. A nice sturdy jack is a wonderful 'get the job done' tool.
It is good to keep a jack in tune for cleaning board faces and a jack for the shooting board. Those are both important uses for a tool of this size and shape. But a jack that doesn't mind a bit of rattling in a tool box, being adjusted to suit the task and isn't afraid to take a nice thick peel of wood, is one of the most valuable tools you can own. I find that with a nice keen edge, and a good even push, I can take off a nice thick chip, without ripping it from the wood.
Taking a thousandth of an inch off at a time when you are shaping a hunk of wood that cannot yet be called a board, is like starting out sharpening a blunt axe on a 1000 grit stone.
Bob
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toolmakingart.com
When you have eliminated all unnecessary wood, then whatever remains, however well formed, is too small to serve as originally intended.
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evenfall
Cow Tipper
Registered: 04/19/05
Posts: 5370
Loc: Sacramento Area, CA
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Bob, and Bob,
Don't assume I will only take a small shaving as a rule. You would be wrong. Also don't assume I don't compare my own observations of what I see happening with my hand tools to that in published sources. You would be wrong again, and I don't necessarily agree with everything I read. The Crux of this thread is based on the fact that Chris Schwarz does not agree with what has been written, and I concur, Chris has had observations similar to mine.
If a chip breaker takes a 45 degree, bevel down bedding and helps the cut chips see a 60-70 degree angle to aid in the proper, further severing of wood fibers, then it must really be helpful when the blade is dull. If this is the fact we are relying on to justify the chip breaker as a necessary evil, it is a wonder a bevel up planes can plane wood at all. I mean since there is no chip breaker then where is all the wood failure? In the woody with a wedge, no chip breaker. Where is all the wood failure? I still think the chip breaker does more to help the cap iron transfer pressure near the bevel than it does to aid the ejection of chip. I am saying most specifically that while I suppose it helps a little, A little is all it is really bringing to the table.
A scrub takes a very thick shaving and no chip breaker. Hmmm... I wonder how it gets by without?
My own comparative experience is more valuable to me when I need to make a decision. At the same time, don't assume I will try to take a shaving that is unnecessarily large either. I don't like gambling the consequences. Taking a shaving as CedarSlayer described earlier today, with the Iron chattering and the wood jamming itself under the cap iron, is quite amusing, likely to break the fragile tote on a Stanley in half through sheer force of effort, and bork up the wood beyond all repair. I would not advocate setting a plane up for that.
I also wont qualify what the Noob or uninformed user will try to do, nor am I looking to rescue them from themselves. Playing in their lessons will not teach them much, especially when they regard a plane as something they would rather not use. When things work best, we are using a tool the way it was designed to use it and we will have endeavored to learn how that is.
At the end of the day, I'll side with Chris Schwarz. The chip breaker is over rated. He observed many of the same things I have and he isn't agreeing with the writers of traditional wisdom, either. 
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~Rob
http://www.evenfallstudios.com/woodworks
Woodworking Knowledge, Skill Development, Discussion
"It's psychosomatic. You need a lobotomy. I'll get a saw." 
Calvin & Hobbes
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Todd Hughes
Member
Registered: 07/29/04
Posts: 4792
Loc: Md. eastern shore
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evenfall said:
Circa 1770.... Figured, apparently. Adequately smooth. Hmmm. Oh Yeah, Pre Bailey Chip Breaker...
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Well guess I could show some pretty impresive north west indian wood carvings done befor they had access to steel tools but that wouldn't be much of an augument that a sharpend beaver tooth is a better carving tool then an Addis chisel...or that the carvers didn't gladly move up to the better tool when they could.
By the late 1700s cap iron planes were becoming more popular then single iron planes, the 1791 inventory list of Christopher Gabriel a London Tool merchant, lists 2136 cap irons even by this early time they had become more popular then single irons.
Cap irons blades got sold for one reason....wood workers wanted them and were willing to pay more for them. Hard to believe that these experanced wood workers who depended on thier tools to make a living and were not flush with the green would pay extra for somthing if they were not convinced it was a better tool. Single iron wood planes were still being made and sold for a good bit less then cap iron planes but soon became unpopular with most wood workers prefering the double iron planes.
...Is interesting that while today some may think that these wood workers didn't need these double iron planes they certainly didn't think so...and were willing to pay a large premium to buy them. .....Todd
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What "i think" is that you have a social disorder, and you're using this forum as a display for it.....DW Pugh
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evenfall
Cow Tipper
Registered: 04/19/05
Posts: 5370
Loc: Sacramento Area, CA
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Yeah Todd,
it is likely that the cap iron design allowed for a tighter clamp on the blade near the cutting edge, easier to adjust than tapping on a wedge. I imagine it was a boon to production. No doubt popular, it made things easier on the woodworker.
As to Northwest Indian Carvings? Grew up in and around Seattle. Been there, seen that. Lots of beautiful work and some still try to continue the traditions. There are a number of places who try to sell their work too, but the concern has been with Northwest Tribes that many of the Tribal Youth are not interested in learning old ways, and the old timers worry there will be no one to pass the traditions down to.
Sounds kinda familiar...
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~Rob
http://www.evenfallstudios.com/woodworks
Woodworking Knowledge, Skill Development, Discussion
"It's psychosomatic. You need a lobotomy. I'll get a saw."
Calvin & Hobbes
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lwilliams
Member
Registered: 04/15/06
Posts: 294
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Sorry for the belated reply. Work has been a bit demanding lately.
Gary quotes Charles Holtzapffel to explain why cap irons work:
Gary Blum said:
Here are some thoughts from Holtzapffel's Mechanical Manipulation and Turning Volume II, 1856.
...."The same effects are obtained in a much superior manner in the planes with double irons, such as in Fig. 325, the top iron is not intended to cut, but to present a more nearly perpendicular wall for the ascent of the shavings, the top iron more effectually breaks the shavings, and is thence sometimes called the break iron. ...
"The constant employment of the top iron in all available cases, shows the value of the improvement; and the circumstances of the plane working the smoother, but harder, when it is added, and the more so the closer it is down, demonstrate that its action is to brreak or bend the fibres. This is particularly observable in the coarse thick shavings of a double-iron jack plane, compared with those of the same thickness from a single-iron plane; the latter are simply spiral and in easy curves, whereas those from the double-iron plane are broken across at short intervals, making their character more nearly polygonal; and the same difference is equally seen in thinner shavings, although of course less in degree."
"In all ordinary planes the mouth gets wider as the iron is ground away, because of the unequal thickness or taper form of the blade............The smoothing and trying planes are also made with metal soles, and with single irons of ordinary angles, as one great purpose of the top iron is to compensate for the enlargement of the mouth of the plane by wear, this defect is almost expunged from those with iron soles, and which are gradually becoming common, both with single and double irons."
If the cap iron stiffens the blade or helps in bedding the blade, it seems these benefits surfaced later, with the introduction of thin blades and more uneven seating of the blade on iron planes. Under ideal conditons of a tight mouth not worn on the sole and especially higher bedding angles, the cap iron seems superfluous. In the real world of the nineteenth century, where wooden planes were used all day every day and the soles and blades wore out rather quickly, the cap iron seems to have been a welcome improvement as evidenced by its almost universal acceptance at the time. They had to have been a lot of work to make at the time and were extra expense for the manufacturer in a very competitive market. Its fair to argue whether the cap iron is useful for today, but to pass judgement on its usefulness back then from our perspective of the 21st century I think misses the mark.
Kind Regards,
Gary Blum
Ahhh, I see. Cap irons deflect the shaving up at a greater angle than the actual included angle. But, but double iron planes replaced earlier planes with traditional cutting geometry. As soon as they were introduced York pitch, middle pitch and half pitch planes vanished from the market. So Holtzapffel was saying that double iron planes, in simulating the traditional cutting geometry, did it better? Hmmm, it seems that Chris Schwarz's experience is similar to mine. Cap irons don't actually do it better.
Charles Holtzapffel, like his father before him and three generations after him, was a tool merchant. Their firm, founded by the elder John Holtzapffel, specialized in "gents" tools--can you say hobbyist woodworkers? Picture the business of a tool dealer in just smooth planes. On one hand they can buy, stock and display single iron planes in four pitches or they can stock just one common pitch plane that sells for more and they can claim it works just as well. Have you ever looked at the difference in dimensions in smooth planes with different bed angles? They require different bodies and wedges. If you were a plane maker looking to do volume production which would you rather deal with, four different bodies and four different wedges with the added advantage of having to do more precision work or to deal with one plane size that allows the claim that the cap iron takes care of the need for those other planes. I can sure see why ol' Charles thought cap irons were great.
But did those in the trade buy into it. I don't think so. Just like woodworkers following Stanley's cheapening of their line, woodworkers of old turned to the used tool market. There's always been a brisk trade in used tools as the multiple owners marks on old planes easily shows. Did you ever wonder why those once common old single iron planes in steeper pitches are so hard to find when molding planes of the same period survive by the thousands? You know, someone even took the single iron smooth plane out of the famed Seaton tool chest and left the double iron smooth plane. I think those old planes were highly desirable and eagerly sought after by tradesmen of the time.
Oh yeah, lets look at the claim that single iron planes became just the cheapest available. That's not true. Companies like Greenfield that offered premium lines of planes included single iron planes in their premium lines. Those single iron planes sold for more than the double iron planes in their regular lines.
Did the professional woodworkers freely accept the claim of the superiority of cap irons? Hmmm, hard to prove. However in places like Great Britain where the bench trades survived and thrived well past WWII one can get a glimpse of trade practices. Here's an interesting post from a similar thread on a forum that deals more with plane making:
http://www.handplane.com/Forum/forum_entry.php?id=252
I've yet to see anyone claim that planes with double irons perform better than single iron planes at steeper traditional bed angles.
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LENPAM
INFILL MAGNET
Registered: 04/03/05
Posts: 8766
Loc: PORT CLINTON,OHIO
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I would agree with Chris's observations,there is no chip breaking only clearing of wood already cut by the blade. I also agree in the blade stiffening effect on thin blades. I don't know about the university study but I don't see how a cap iron,chipbreaker or top iron can influence tear out other then stiffening the blade,Len
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INFILL MAGNET
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AHill
Member
Registered: 01/16/06
Posts: 2914
Loc: Antelope Valley, California
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leonard_bailey said:
Andyman said:
Does a chipbreaker really break chips?
Yes it does 
Them are MDF chips - not authentic chips. Try again with real chips. 
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Still Learning,
Allan Hill
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