Cambered Plane Blades... Historical?

[Erich Weidner]

Does anyone know if historically,woodworkers cambered their irons? Or is this a modern adaptation?

The oldest reference I own is the "Planecraft" book originally printed in the 1930's. It has all of about one sentence on the subject:

"If course and rough work is in hand, the blade may be ground as in "D" (illustration D is a cambered edge). But this will result in a series of corrugations which must later be removed for a nice finish."

[Jim Koepke]

Does anyone know if historically,woodworkers cambered their irons? Or is this a modern adaptation?

The oldest reference I own is the "Planecraft" book originally printed in the 1930's. It has all of about one sentence on the subject:

"If course and rough work is in hand, the blade may be ground as in "D" (illustration D is a cambered edge). But this will result in a series of corrugations which must later be removed for a nice finish."

The cambering of blades may have occurred unintentionally. This could be either by an accident of technique or it could be from worn stones. At one time moving the blade in a figure eight was a popular honing technique. This could lead to a slightly cambered blade. There have been some accounts of corrugations being found on older work.

Today it seems some insist a cambered blade is the only way to go.

A Stanley Tool Guide from 1941 doesn't mention cambering the blade. It does mention rounding the corners of the blade to reduce the occurrence of tracks in the work:

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jtk

[Tom M King]

How old do you want to go? I can show you hundreds of square feet in houses from the late 18th Century, into the early 20 th Century, that have been finish planed with a cambered smoothing plane iron. If the iron is not cambered, it will leave tracks with sharp ridges.

In working on old museum houses, I get paid to replace parts that match as closely as possible. That includes texture, on finish surfaces, to match that left bys the old smooth planes. I have never seen any that only had the corners of the iron relieved. Both of these pictures are new work. The texture might look severe in these pictures, but it can only be seen in a strong, raking light. The "hollows" are only a few thousandths deep. I have some pictures of the old, but not stored in these forums.

[Warren Mickley]

Moxon mentioned that fore plane irons have a "Convex-Arch", writing in 1677.

As a practical matter you want the camber for each plane to be in relation to the depth of cut you use for that plane. A jack plane has somewhat more than smoothing plane for example.

If in use your iron only cuts in the center, you have too much camber. If the edges dig in there is not enough camber.

[steven c newman]

Hmmmm...
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[Tom M King]

I'll try to remember to take some pictures of old work this week, since the question was about Historical. I will be where there are plenty of available boards.

[Doug Dawson]

Does anyone know if historically,woodworkers cambered their irons? Or is this a modern adaptation?

The oldest reference I own is the "Planecraft" book originally printed in the 1930's. It has all of about one sentence on the subject:

"If course and rough work is in hand, the blade may be ground as in "D" (illustration D is a cambered edge). But this will result in a series of corrugations which must later be removed for a nice finish."

I suspect that cambering the iron was sufficiently intuitively obvious that it didn't bear mentioning, for the most part. Name some historical figures, particularly in the trades, that were as chatty as we are today. :^)

[Jim Koepke]

I suspect that cambering the iron was sufficiently intuitively obvious that it didn't bear mentioning, for the most part. Name some historical figures, particularly in the trades, that were as chatty as we are today. :^)

They didn't have the many ways of being chatty as we do today.

Tom's images make me wonder about the different 'trades' of the 18th century. Those making buildings and those making furniture may have had different criteria on how a finished surface should appear. There was also likely a difference between those making furniture for the average citizen and those making the finer furnishings for those who could afford the extra cost.


Moxon mentioned that fore plane irons have a "Convex-Arch", writing in 1677.

[edit]

If in use your iron only cuts in the center, you have too much camber. If the edges dig in there is not enough camber.

That supplies the historical reference and the explanation of why it may not be noticed on finer work from the time.

jtk

[Tom M King]

Smoothing planes were plenty good enough for a lot of house parts, and country furniture. They still got the final surface for fine furniture close too, but I expect the smoothing plane was followed by a scraper, or various other methods for final flattening. I do the house stuff, and I think Warren works more on furniture (don't really know), so expect he knows more about furniture finish surfacing in the past.

Even those outside steps, and shutters look like they have flat surfaces unless they are seen by a harsh raking light. I took that picture of the steps, that run East/West when the Sun was very low in the West. The shutter picture was taken just as the Sun came past the corner of the house, so both had very strong sidelighting (raking).

In taking pictures of the old surfaces, or just looking at them by eye, most of the time you need to lay a light, like a flashlight, laying directly against, and shining across the surface. Otherwise, they just look like any flat board today.

[Winston Chang]

This recent post on the Mortise and Tenon Magazine blog has some pictures of Shaker furniture. Some of the hidden surfaces have a texture that comes from a heavily cambered blade.

https://www.mortiseandtenonmag.com/blogs/blog/issue-07-t-o-c-a-shaker-s-perspective-on-his-community-s-craft

[lowell holmes]

I sharpen my plane irons on diamond hones. I only grind one if it is in rough condition.
This applies to chisels as well and Buck knives.

[Erich Weidner]

I'll try to remember to take some pictures of old work this week, since the question was about Historical. I will be where there are plenty of available boards.

That would be very cool!

[Tom M King]

I did remember to take some pictures, but had a hard time catching the "texture". I'll post what I took in a bit. I have a 4x6 LED light on the good camera, and thought that would work if I too it off the camera, and held it against the wall, but I don't think it worked very good. I'll see when I get the pictures onto the computer, and post what I was able to get.

[Tom M King]

Looks like I wasn't able to catch the lighting right today, either with my light, or the 9:30 morning sun. These boards cover the walls in the third floor attic in an 1828 Plantation house. The board mostly by itself in a picture is 17" wide. Their smoothing plane texture pretty closely matches that in my previous two pictures.

I took a picture of those same, gray steps this morning, but as you can tell, you can't really see the texture without a very strong raking light. There are 10 years between those step pictures, but the texture is still there. The Sherwin-Williams Industrial Enamel has held up fairly well, but probably should be recoated fairly soon. I did see that house is due for a pressure washing.

I measured the depth of valleys of some of the older texture, but didn't have feeler gauges, so I used the corner of yellow, lined notebook paper, which I know to be 3 thousandths thick. One corner of the paper will go under a straightedge (4" Starett combintion square), but two won't fit.

I'll try to do better another day. I'll try to remember to take the good camera tomorrow, when we'll be at a 1798 house.

[Tom M King]

Here's another picture of those shutters. You can't see the smoothing plane texture on those either without a strong raking light. The balustrades are "neanderthal" too, because the easiest way was to mark each piece, and cut to the line with a backsaw. All heart Cypress, installed with hand forged nails we saved from the original Cypress shingle roof on this house.

Vanish on the entry doors is not authentic, of course, but by the time we stripped them to correctly reposition the panels, I couldn't make myself cover the gorgeous Heart Pine with paint. Even the purists have not complained.

[Warren Mickley]

In historic furniture work, each of the bench planes (jack, trying, jointer, smooth) has its own characteristic camber. I will make some remarks about the smoothing plane.

The smoothing plane is used to clean off marks, scuffs, dirt, and such just prior to gluing up or just prior to finishing. Because it takes very thin shavings, the camber is very small. In practice a camber this small comes naturally because our sharpening stones tend to hollow. In looking at a piece of furniture the scallop surfaces in these pieces are generally not noticeable by eye nor by touch. However, putting the surface in a most favorable lighting will often enable one to see the planing marks. It is some trouble to see them. Good work has smooth plane marks that are full length, straight with the grain, and regularly spaced.

[Tom M King]

I did remember to take the camera with me today, but once again, I didn't have the right kind of light. I think I was probably really lucky to be in the right place at the right time to catch my first couple of pictures in this thread. I won't take more space here to load pictures that don't tell the story.

edited to add: I saw Warren's comment on straight smoothing plane tracks. I see straight ones mainly on pieces of furniture. The only house part I remember ever seeing straight tracks on was a door in the 1805 Hope Plantation that had straight tracks on the stiles and rails. I remember that striking me as unusual for a house part.

For house parts, it's more of a "get it done" thing, and they will go straight for maybe most of a part, but then change to multiple directions. I have a short video somewhere of me planing those step treads in a yard on a sawhorse, but don't remember where it is. The tracks that aren't straight come from footwork, and arm reach just working out that way. I can't explain it, it just comes out that way. I'm matching replacement parts to original parts in these houses, so don't try to do them one particular way. My elbows are rarely by my side, and I rarely walk while making one stroke, unless I'm trying to leave straight tracks. I would do that if I was building a table.