Est. 1998 — 27 years of woodworking knowledge
Re: A lot of waffle.
thomd [email protected]
>I'm having trouble following this. I thought you were saying the outfeed on a power planer is the same as on a japanese smoother? I must have read it wrong. They seem the reverse to me. I'm kinda flu woosey today...
HMMMM WAFFLES!!!!!
John Clifford
No, but explanation of technique would help
Dave Thompson
>Doesn't concavity of the heel have the same effect (of creating a convex surface on a board)?
I can see how you might think that. However, I believe this is not the case. An explanation of the presumed technique used may help.
As the plane begins the cut on the beginning edge, the weight is applied to the the toe. As the plane leaves the trailing edge, weight is applied to the heel. This technique is used to keep the plane from rounding over the start and end of the board. The weight shift helps insure the plane stays level to the plane of the board as it's entering and exiting.
So, in this case, the plane registers along the same plane as the toe. Because of the weight on the toe, the heel end of the plane is a blade's depth above the wood, i.e not contacting, until the concave end of the heel touches.
Because the weight distribution is on the toe in the beginning of the cut, one ends up with an analogous situation to the infeed/outfeed offset that a power planer has. It would be more analagous if rather than having a concave heal, one had two parallel flat planes (before and aft of blade)which were offset by the depth of cut.
As I mention in my earlier note relating first hand experience of a full length concave trasitional jointer, you can not have a plane which is concave from heel to toe. As the plane leaves the wood, the lead point begins to dive making a deeper cut on the end. Since a fully concave plane is only riding on it's toe and heel (two points), the weight shift technique does not help.
I hope this explanation helps,
Dave
Re: flat soles and straight edges. An Experiment
Dale Stansbery
>Of course, when you consider the flex in a sole created by varying down pressure, front to rear by the user, does any of this discussion really stand up. Or is the longitudinal convexity the key to controlling the flexing. I have no answers, but it seems it could be important.
Second part....
Dave Thompson
>Forgot to address the second part of your point...
When the plane exits the board, any concavity of the heel, will once again cause the plane to dive as the toe comes off the board (the blade will start to lower again), rendering the board convex at the exit too.
A key issue is that the concavity of the heel is only a blades thickness. I agree the tilt will happen as you suggest, but only after the blade has left the board, and so it will have no effect as the plane exits.
Re: flat soles and straight edges. An Experiment
Sgian Dubh
>David, who says that a flattened plane sole is flat in use anyway? I can't prove it scientifically with controlled tests, etc., but I'm convinced I can bend plane soles on purpose to achieve specific results-- I'm convinced I can do it by the results I aim for and seem to get. Twist the thumb and forefinger sides of the hands holding the knob and the handle towards each other to make the plane sole somewhat convex. To bend the sole slightly concave twist them other way.
Anyway, all that matters for an edge joint is to get two edges that match (with a slightly sprung joint preferably) and glue it up. The joint can be a matching S shape or long wavy wriggle too. Many of us have knocked a few of those out over the years for visual effect using a router and a template. Slainte.
Got it, I think! (more mental gymnastics)
Frank D. in Montreal
>Thanks for taking the time, Dave. I think I see the limits to the concavity you're talking about, which are quite specific: the very back of the heel can't be lower than the surface of the toe by more than the depth of cut. Any lower than that, then the back of the toe would eventually be lifted off the wood, causing problems. But otherwise the sole behind the mouth right up to (but excluding) the tip of the heel doesn't really have to be in line with the rest (it can be concave).
Hope I got that right!
Re: A lot of waffle.
Pam Niedermayer - Austin, TX
>No (I think, suppose I could go read it. :), I intended to say that the profiles were the same more or less if you turned the Japanese plane (not a jointer) upside down.
Pam
Re: flat soles and straight edges. An Experiment
Dan Clermont in Burnaby
>I think you may be able to move a Bailey but the LN and Veritas planes have pretty thick soles.
My LN #8 is about 3/16" thick I believe
Dan Clermont
Re: flat soles and straight edges. An Experiment
Dan Clermont in Burnaby
>David
I am sure I have produced several board which are dead flat according to my LN 8 and "cheap" straight edge ;).
But I am gonna now have to run an experiment just to confirm this
Dan Clermont
Re: I'm lost, any quick drawings?
David Charlesworth
>Alan,
To get a straight edge, I hollow with stop shavings and then take no more than one or two through shavings. Job done.
If you take another ten through shavings I predict tht the bump will return.
Hope this makes sense,
David
Thanks everyone!
David Charlesworth
>Thank you all, very much, for those fascinating thoughts and link.
The issue is complex, plane soles do flex, slight convexity is acceptable if not beneficial and I suspect that the Japanese wooden soles have some advantages as the scraping of the sole can be matched to the work in hand, (more difficult on a metal sole!).
I would dearly love to hear from those of you who are prepared to try the experiment.
Start with a straight edge and take ten though shavings. Do you end up with a bump, ie convex edge? or have I dreamed this?
best wishes,
David Charlesworth
Re: Measurements (apex)
Norman (Ottawa, Ont.)
>David,
I have a question.
In your findings where along the edge is the apex of the "bump" , is it always consistent. We can use the location of this apex along the length of the edge of the convex surface to perhaps help determine why or how it originates.
I too thought it is due to the fact that in the first and last part of jointing only the toe or heel rest on the surface (in that order), but this only makes sense for the initial jointing when the toes of the plane is only on the edge. In the last phase the toe drops off the edge just as the blade exits the edge , this should not even be an issue then.. And in the former, the apex would consistently be towards the beginning of the edge.
If we somehow find where along the edge the apex or crown of the convex surface is, this might help in determining the cause,
especially if it is consistently at the same point along the edge..
BTW, I now succesfully use your principle of taking a couple of more shavings from the middle part of the length of the edge to produce a
miniscule spring in the boards to be jointed.
Norman
Re: Measurements (apex)
David Charlesworth
>Norman,
On the 15" edge which I usually use to demonstrate, with a 5 1/2 plane, the bump seems to be consistently about 2/3 of the way along the edge, ie towards the end of the planing stroke. This is from memory, I will be able to check this out more carefully after a few days of workshop tidying for the new 3 month course!
David
Not exactly the experiment,
Paul Kierstead
>But a couple of observations:
Whenever I use the #5 to take the sawmarks out of the edge, I always end up with a convex edge if my sawing was any good at all.
If I have an straight edge out of square, and struggle some to put it back in (taking quite a few shavings in the process), I end up with a convex edge.
At first I chalked this lack of experience, but I have done quite a few boards since. Then I chalked it up to poor technique (you can have 50 yrs experience and still have poor technique) so I started to really pay attention to my weight shift. This helped a little, but it was still there. Finally, at the end, I just started to take a couple from the middle and then a full swipe at the very end. So my experience correlates with your proposed results of your experiment. The odd thing is I never considered taking advantage of it; I always tried to make it straight first and then made a correction for my 'mistake', rather then make it hollow first off and then straighten it. Certainly something to think about.
You could test this, couldn't you?
Bill Houghton, foggy mornings in Sebastopol, CA
>It would seem easy enough to test: if you had a surface plate or similarly flat surface, you could have a friend see if s/he could fit a feeler gauge under the sole as you flex the plane resting on the reference surface.
Re: Measurements (apex)
William Duffield, on the Cohansey
>I suspect the locationof the hump would be highly dependent on the length of the plane in relation to the length of the board, and also to the blade exposure. I wonder if you used a Veritas plane, with a longer nose, in relation to heel, if the bump would move back?
I am amazed at how much our understanding has progressed since Forrest Addy posted his thoughts here over three and a half years ago. (Reference Bob's post on Cosmic Truth, above, if anyone missed it.) Like Bob, I wasn't convinced at the time, either, but I continued to consider his arguments, and observed my own results, until I decided he was probably right, mostly.
In the meantime, I also learned how to put a spring joint in a pair of boards using a power jointer, but more important, I learned that a lot of skill, and trial and error, and checking your results and adjusting is required to get it right. You can't just give the outfeed table depth wheel a crank, throw the board on the jointer and push it through.
The amount of sole concavity behind the blade would seem to be very tightly coupled to the blade exposure. This seems to be a good argument for multiple jointers in our arsenals, and for planes with precise depth adjusters with miniscule backlash. However, precision machinery cannot control the amount of downward pressure you put on the plane, the flexibility of the sole, and where in the stroke you shift your weight from the knob to the tote. On very long boards, where you need to take a step or two or three in mid-stroke, relying on shifting your weight between tote and knob is a lot less consistent method than relying on the stiffness of the board, the stiffness of the bench, and the stiffness of the plane, or better yet, on your eyes and ears and finger tips. Listening to the plane as it cuts, watching the shaving as it comes off the blade, and laying the boards together on top of the bench every so often to look at the joint you are making is the way to "get to Carnagie Hall."
Re: Thanks everyone!
Warren in Lancaster, PA
>I tried the test and had no convexity (or concavity) after ten passes. I have a lot of experience.
After blade contact
Pam Niedermayer - Austin, TX
>Dave replied on the Hiraide forum that he has a small coplanar area at the very back of the jointer planes, so he's got 3 coplanar areas. Is this what you meant by contact? Or a completely flat sole? Or....?
Pam
In practice
Greg B
>David,
Always thought provoking. Thank you.
You got me started off on the right foot a few years ago. Since then, I've always had "bumps" on my mind! I'm mindful of bumps when sharpening plane irons, chisels, etc..., as well as when preparing faces and edges.
I try to put slight hollows in all faces and edges. Just finished two small cabinets in padauk and am completing two boxes in koa and quilted maple. Instinctively incorporated small hollows in all surfaces via the stopped shaving method. Sharp irons make the planes do as I ask.
Since this is so fresh in my mind, I wonder if a truly objective experiment can be done with the human hand. In other words, your cautions and my experience have conditioned me to have great concern about creating bumps in precious materials. All entries and exits from shavings are made with bump avoidance in mind. If I consciously abandoned this concern, wouldn't I be trying (pardon the pun) to introduce a bump? Don't know if my hands can be objective anymore.
On reflection, though, there was one catagory of surfaces in these projects in which hollows were not intentionally introduced. These were the miters at the corners of the cabinets and boxes.
These were set out very carefully with knife lines (as you suggested), cut almost to the lines on the table saw, then shot with a very sharp #9 on a shooting board using a 45 degree carriage. These surfaces were shot right to the knife lines, which were made carefully to ensure the waste side of the line got the bevel.
Obviously, the shooting board didn't permit incorporating a hollow. It also didn't permit the plane to start too low in the beginning or to dive at the far end. It supported the sole in its entire travel.
So, master, what causes these "bumps". Is it so much a question of flatness of sole, or is it whether the iron is supported throughout the shaving? When we make a stop shaving, are we creating (or leaving) support for the sole during the hollowing passes, somewhat similar to the support our shooting boards give us? I've never shot veneer sandwiched in mdf supports, for example, but are these edges in danger of becoming convex?
Cheers,
Greg
Re: You could test this, couldn't you?
Sgian Dubh
>Indeed I could Bill, and I probably really ought to now that it's been brought to the fore of my mind again. I recall making much the same comment some months ago in a similar thread-- I don't recall where, and it occurred to me to do a test then.
I forgot all about it and just carried on preparing edges for gluing up 'bending' my plane and other dodges as usual. Most of the time I've no real concsious thoughts on technique when I'm working. I just do stuff and it comes out right.
But, now the 'technique' has been mentioned again I'll see if, 1., I remember, and 2., Try to make time to do a bit of highly unscientific testing. I guess I'll need a third hand to take a snap or two as well-- it gets more involved and complex by the minute, ha, ha. Slainte.
Re: Spin 180
thomd [email protected]
>Clamp your plane in a vise and run a straight piece of wood over it 10 times. Piece longer than the plane, piece no longer than the infeed.
Food for thought
Dan Clermont in Burnaby
>I have been too busy around the house to test this and I apologize if my response mirrors some others up above as I haven't had the time to read all of the responses.
Is it possible the position of the knob and tote and the downward pressure by the user cause the toe and heel cause the plane sole to become concave and therefore the middle of the stroke where pressure is evenly distributed?
If that is the case then a concave sole would hinder or make the problem worse and one would want a Convex sole which would be equalized and become flat by the downward pressure above the knob and tote.
Soon we will all have to by planes based on our downward pressure weight above the knob and tote.
Food for thought
Dan Clermont
Re: In a perfect world
thomd [email protected]
>OK, then that's wrong. The planer outfeed is higher then the infeed, while it is lower on the Japanese plane. If niether had a blade in place, then the object run along the planer infeed would crash into the outfeed table, while it would be above the outfeed on a J. plane.
Where there is some similarity is that both types have outfeeds that are below the level of the blade. But the reason is different. The planer does it so that with the intermitent cutting action the board'd waffle peak will be the same height as the outfeed, and the outfeed will support them (with a few thou here or there for what kind of joint shape you want). On the J. smoother the outfeed isn't really an outfeed at all it's just there, and it's relieved so the blade wedging effect and different degrees of insertion won't interfere with the index function of the wave pattern on the infeed.
I was thinking about the J. jointer yesterday, and wondering how one was really intended to set it. When one gets into this level of discusion I don't find official sources are much help because they don't teach this way, and even if they did they probably wouldn't agree on all details.
Seems to me there are two ways to deal with the Japanese jointer. One is to set the blade, and then use three sticks to set the sole height to the same level. If this is done then for that one setting everything lines up.
The other option is to set them with the blade not set so hard, and then when you fully set it you arc the sole and you get the concave sole. I have several compass planes so I have played with convex longi soles, and it does work, but I wonder what the ancients had in mind.
A third option would be the first combined with the second, flat at the light setting and more curve at the higher setting, or variable curve with the result that you don't get with a stanley, that different cut depths sorta net out on joint spring. So deeper blade would not create more joint gap, in a perfect world.
Re: After blade contact
thomd [email protected]
>One classic set-up is the two Co-Ps on the in-feed and then a hollow from the back of the opening to back of the plane with a third contact there. I think there are other options. Three points is how I set it up. You scrape a hollow all the way behind the blade to deal with any bulging from different seatings of the blade. However the rear Co-P can rise and fall with blade seating, see my post above re, speculationon that point. P 92 of Odate has info on planes for straightening.