About handplane design

Page 1 of 2  
Hello,
I am just an amateur woodworker, who just awhile ago got into building handplanes. I like krenovian approach (gives me an excuse to use combinations of flashy hardwoods :). I have finished now about a dozen wooden handplanes and conditioned (or actually re-built) some cast- iron english Stanleys and one Anant smoother by machining their soles and sides, mouths, beddings and assembly surfaces with a precision milling machines and other such methods. I think they work now as well as those expensive (and beautiful) Lie-Nielsens and Veritas planes. Well, I'd say the Anant smoother costs now about 400-500 USD :). Nothing further on that, just to say that now I have some preliminary experience about making and conditioning planes to somewhat useful woodworking tools.
Okay, during these exercises, it got me thinking one seemingly fundamental design-based thing, on which I have not yet found discussion or comments anywhere. It may be because english language is not my native language and that's why I have missed something. But it still bothers me, and I still I would like to receive some comments and guiding in this matter, which actually fights against certain fundamental classic design principles I have used to keep as rock- solid approach when talking about woodworking handplanes.
Consider the side profile of for example Stanley #5, just to mention one basic design. It's side profile starts as shallow at toe, rising along the side where blade is and then again decreases to the heel. This side profile says that the body construction is most rigid against mechanical bending in the mid-section where the blade and it's adjustments are.
The plane iron itself, when you push the plane forward and blade takes shavings, will create a force which pulls the sole against the wood surface. Then again, when I think of the generally accepted principle that plane sole should be levelled at least at toe region, at heel region and especially at the area right in front of the blade edge, it means that if there is very rigid mid-section structure, the sole must be no only incredibly flat to work well, it is in some cases also difficult to avoid tear-out in very figured wood if the sole region in front of the blade does not stay pressed against the wood surface to be planed. Quite unforgiving system, I'd say.
So, the bothering question is that why plane profile could not be allowed to be a bit more flexible at that region where plane blade and the surface area are? I do not mean paper-thin soles or clearly "springy" action or such, but just enough to utilize that force created by blade. It would still not mean loss of rigidity beyond practical level.
This bothers me, the question why general design fundamentals consider such an unforgiving structures for cast iron handplanes. I know, it works, I have experienced and even created it by myself. I have also experienced surprises that it does not work although everything should be in order. Then again, I have found that I score with better surfaces with wooden planes more often than with cast iron bodied planes despite they are nominally more accurately adjustable. Could it be that this "flexibility" is readily available in the more elastic behaviour of the wooden sole? I somehow do not think that this difference appears directly because of my contribution. For example, due to my day job, I have access to machinery that makes really very true surfaces (for flat surfaces manufacturing, human craftsmanship has really no deal compared to how those machines do and measure their job) and I have for a curiosity done surface truing for some handplanes with them. The result is kinda clear, with similar settings of planes (iron angle, mouth clearance etc.) wooden plane sole works better more often than cast iron plane. To me, this result is also a kind of evidence to support the existence of my current disturbing thoughts of "flexible" sole. I say that I am not starting a crusade, not even arguing anything but just presenting my experiences.
But because here in this newsgroup there seems to visit both professionals and very advanced amateurs, I decided to ask this here. Please, bear with me :)
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 16 May 2007 14:21:03 -0700, snipped-for-privacy@gmail.com wrote:

While this is true as an observation, I don't believe it's a significant force in comparison to the downforce with which I push down on the plane body.
I'd also note that recent Anants are incomprably better to their production of 5 years ago. They're now better than modern Stanleys for build quality.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hello,

Precisely so. If I am an average Finn, of height 184 cm and weighing 90 kilos, I would think that the portion of my body mass I use for plane operation would exceed the downforce created by blade. But I think this is not yet the complete reason for different behaviour of the different plane body structures I am experiencing, because the question is actually how to keep the region in front of the blade pressed against the wood surface in that case when plane body is very rigid. If it does not stay there, there will appear some disturbing tear-out. I also think that my planing as an operation is very much typical and pretty much similar as seen in those educational DVDs from master cabinetmakers.
When using a traditional bench plane, You press it against the wooden surface at the end regions of the plane body. In front of the front handle, as behind the rear handle there is some sole area, the most important areas with the area right in front of the blade. You do the same thing with both cast iron plane and wooden plane. In my case, I think I have witnessed the difference between these planes, and I would like to figure out actual reasons behind it.

I am glad to hear it is possible to score with decent planes with low expenses. I hope it would bring more people to the joys of woodworking :)
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Might I suggest that you take your question to the Old Tools (Galoot) group?
There are people who know more about the use and design of planes than almost anyone, and best of all they don't flame each other.
snipped-for-privacy@ruckus.law.cornell.edu
Might be very interesting.
Old Guy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

An intriguing and thought provoking question.
I certainly hope someone can do the question justice because, if so, it would sure be a discussion worthy of observation.
I wish us both luck! ;)
--
www.e-woodshop.net
Last update: 2/20/07
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com wrote:
: The plane iron itself, when you push the plane forward and blade takes : shavings, will create a force which pulls the sole against the wood : surface.
Interesting point. The blade will also bend, and can create chatter when it repeatedly bends down, snaps up, bends down, etc. And this gives a messed-up surface.
Then again, when I think of the generally accepted principle : that plane sole should be levelled at least at toe region, at heel : region and especially at the area right in front of the blade edge, it : means that if there is very rigid mid-section structure, the sole must : be no only incredibly flat to work well, it is in some cases also : difficult to avoid tear-out in very figured wood if the sole region in : front of the blade does not stay pressed against the wood surface to : be planed. Quite unforgiving system, I'd say.
True. There was a discussion of the degree to which soles flexed during use (and also during the tightening of the blade cap) on the Oldtools list. It was several years ago, but the whole list is archived at
http://people.iarc.uaf.edu/~cswingle/archive /
Jeff Gorman, who used to post here, did some measurement studies.
: So, the bothering question is that why plane profile could not be : allowed to be a bit more flexible at that region where plane blade and : the surface area are? I do not mean paper-thin soles or clearly : "springy" action or such, but just enough to utilize that force : created by blade. It would still not mean loss of rigidity beyond : practical level.
I think it would, actually. The blade engages the wood by protruding from the sole a small amount. Ideally, you want the horizontal movement of the blade to be in a straight line. If the sole is flexing, the blade would go further down, then snap up as the casting bewnds back, over and over again.
Ideally, you'd like the blade to be, say, welded to a totally inflexible plane body, so there's absolutly no up and down movement of the cutting edge. If I remember the Oldtools discussions correctly, there is more of this vibration than you would think, even on a hefty iron plane body.
    -- Andy Barss
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Which is why when lapping a plane sole you must do it assembled and tightened down. I took a 1930s Stanley smoother with a concave sole and got it touching at toe, in front of the mouth and heel. It cuts beautifully now, runs over knots in pine like a dream.
Peter
--
Add my middle initial to email me. It has become attached to a country
www.the-brights.net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hello,

Chattering of plane iron is of course a problem in some cases, caused by the fact that plane iron is hardened steel or similar, providing very low internal value for mechanical damping, and it is used to machine wood, which is structurally and mechanically speaking both anisotropic and periodical material. I think You have heard the high- pitch howling, almost squealing sound emerging from plane throat while planing. Plane advances about at walking speed, cutting these a few micron of diameter regions of wood fiber in a row. The result for 1st mode frequency is regularly at kHz levels. Higher modes follow, contributing their part for the tone. Vibration of the blade is therefore inevitable, but only thing to avoid is vibration frequency for blade-bedding resonances, which is the main cause for devastating chattering.
It is true that any length of plane iron, protruding from sole would also have the momentum of it's length. When worked against periodically composed material, it actually will vibrate, no matter what kind of plane body structure there is. Factors like iron thickness and plane body heft will affect in it, but will not remove it because it is direct consequence of the working blade edge. Infinitely rigid plane with minimum protruding length of plane works only on surfaces needing no planing anymore, so to speak :)
My problem is still a bit different in details, I'm afraid. The wooden surface to be smoothed is not flat, yet. Plane has to be used. It is also so that real wooden surface will never be absolutely flat, also plane sole surface is not absolutely flat. There does not exist infinitely rigid surfaces, but there is great difference in rigidity between wooden sole and cast iron sole. Like I said before, I score with better surfaces more often with wooden soles. I like Stanley-type of planes because they are incredibly comfortable to hold and appear as "discrete machines" which is great, but they do not work so reliably as wooden planes, because of those sudden surprises I have experienced.
The downforce of advancing plane iron taking a shaving increases up to some level along the planing speed. It must be reasonably high, because everyone who has catched a just-planed shaving on the back of the hand, can tell that it is warm. The heat implies to a significant amount of energy needed to take the shaving off. Part of that energy is undoubtly consumed in creating the downforce. The main problem actually is that for finishing smoothing, the shavings are very thin, like 0,05mm thick or such, and at that point the region in front of the blade should really stay pushed against the wooden surface. This causes the problem I have observed and would like to receive some kind of satisfactory answer: why very well prepared cast iron sole does not _necessarily_ provide the same consistent performance as wooden one? Is it because of higher elasticity/compressibility of wooden sole? Does wooden blade bedding provide more mechanical damping to resist chattering (it does, but it is undoubtly not the whole explanation) ? What else could matter here this much?
I am still not arguing anything, just asking quite a difficult thing. I'd like to use more those metal planes because they feel good, but I must say the wooden ones are as comfortable. I could shut my mouth and stick with the woodies, but if I do not understand why some of my tools do not work, it's just too disturbing not to talk about :)
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On May 17, 6:24 am, snipped-for-privacy@gmail.com wrote:

well, a test. make a wooden plane with the same configuration as one of your iron ones- same weight, blade angle, toe length, heel length, every factor you can think of, and use the same blade in both. compare performance. one difference that remains is the material comprising the sole surface- wood vs. iron. they have different textures, among other things.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hello,
On 17 touko, 20:33, snipped-for-privacy@yahoo.com wrote:

Yes, there readily is such a wooden plane. I did not make it, I inherited it from my grandfather who made it according to Stanley #5 dimensions and functions. It is not a wooden replica of metal Stanley, but looks like a regular european style of wooden plane. But I think just a wooden replica of metal Stanley may not quite compare, and besides now when I have experienced this difference already with conventional style of wooden planes, I think I should actually make this other idea I have had for awhile.
I have one more english Stanley #5, to which I could the following modification. It is possible to machine about 2mm off the thickness of the sole, and replace it with a slice of rosewood or cocobolo of similar thickness. I would think that some suitable flexible epoxy adhesive would hold the piece there. The point for this experiment would be to see whether the reason of this behaviour would lie in the more elastic contact behaviour of wooden sole, or would things still remain the same.
But before anything happens, I would like to hear if anyone has already done something like this? The idea is kinda obvious, to combine the smooth action of wooden sole with rigid frame and all the adjustments. A bit different than those Stanley transitionals, though.
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On May 16, 5:21 pm, snipped-for-privacy@gmail.com wrote:

The force vector against the wooden surface you speak of is virtually non-existent - the reason being that the force is the result of "pushing" against a very flimsy support - the wood shaving your are cutting away while planing. Its been many a year since I took Engineering mechanics, but I think if you draw a freebody diagram of the plane blade itself and draw the arrows representing the various force vectors, you'll see what I mean.
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

That's a way of putting it that I don't often see. May I ask where you studied Engineering mechanics?
todd
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

University of Texas at Austin. My degree is electrical engineering but all engineering disciplines had to take two semesters of engineering mechanics in their freshman year.
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hello,
On 17 touko, 09:07, snipped-for-privacy@gmail.com wrote:

Well, I could draw that easily, but what should I place as values for other forces to solve that equation? For example, how should I measure frictional forces at wood-sole interface during actual planing event? I can imagine the measuring setup, actually I think it has been done somewhere (cannot now remember where).
But I think it is not quite neglible, not necessarily. And solving that is also not my reason for these posts here, although it would be interesting to find out.
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On May 16, 11:07 pm, snipped-for-privacy@gmail.com wrote:

the downward pull is slight, but seems to me like it would fluctuate quite a bit with grain changes.... and remember that the force is greatest right at the edge of the blade, where it is thinnest.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I think you are right Bridger. I don't want to make my head hurt to much by thinking about it to rigorously. :-)
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com wrote:

Good performance is readily achieved with simple lapping with a flat reference surface, silicon carbide sandpaper and patience. Lapping to "incredibly flat" may be time consuming, but is not difficult.

Why would the sole not be pressed against the wood? If the area in front of the mouth is not pressed against the wood, that means the toe and heel of the plane are on higher spots, which will be cut off when the blade gets to it. If the body can flex enough to allow the blade to cut in the valleys, it would only be making a low area lower. You can plane the valleys when the hills are gone.
As a matter of curiosity, I like the see comparative measurements of the rigidity of a Stanley cast iron plane and an equivalent woody. I'm not convinced that there is a significant difference.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, I did that with precision machining and polishing machines. I'd say the achieved "flatness" is at submicron level over entire plane sole of this English Stanley #5 and one other metal plane. I have a reason to believe that human hands are perhaps not capable to perform the same. And yes, the lever cap with blade was tightened during the operation. I did the same with some wooden soles, but I think this accuracy does not hold for long due to the living nature of wood. But it is still incredibly flat, too.

Yes again for the levelling phase of planing. But the problem is with those final shavings, very thin ones giving the polished look. Woodies work better there according to my experiences.

I think too that it is so, total frame rigidity is not necessarily the main cause for these anomalies. But I am starting to think that the answer may lie in higher elasticity/compressibility of wooden sole, which actually is another thing than total frame rigidity. With similar force, You can compress wood more than cast iron, of course.
It could be that when I put a portion of my body mass over the handles, those sole regions under the handles will be compressed to slight elastic and reversible deformation, like some springy pad. That leaves the mid-section of the sole as compressed, too, but now it would have a chance to "live along", meaning that when the plane iron edge contacts some stiffer or harder region in cranky wood, this precompression of that particular surface in front of the plane iron edge will have some holding reserve which would keep the smoother and a bit softer, but more intensive contact there for slightly longer time. Or something like that. Something has to happen there, because this disturbing from-a-distance-visible tear-out seems to happen less often with wooden sole. I can't believe I have confronted just a statistical anomaly, nor I would not blame the wood because I have planed the same surfaces with both metal and wooden planes. Go figure :)
Yours,
Samu
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Would this flex still be an issue if the plane was built like a (stationary, electric) jointer where the feed surface is lower than the outfeed surface by the thickness of the cut? The back/outfeed of the sole would have to be narrowed to the width of the blade I suppose. Obviously this would require a new kind of adjustment mechanism, but someone could sacrifice a wooden plane to make a nonadjustable version and see what happens.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.