Cambering plane blade

[Mark Rainey]

A new plane blade is ground straight across. When cambering a blade by hand, not using a grinder, what are the techniques used. I try to keep the angle ( 30 degrees ) the same but turn the approach of the blade so the left and right edge lead. There is the tendency to lift the opposite side of the blade but I find the process confusing. I am looking for advice for those who camber almost all their blades, smoothing, jack, etc. by hand.

[Tom M King]

For a smoothing plane, all it takes is a bit of extra pressure on both ends of the cutting edge on the final stone/stones. For the others, anything from such pressure on more stones in the process, to grinding the camber in for more extreme cambers. I don't think you want to do the hogging planes by hand. Even for no. 6's, I wouldn't want to camber them by hand.

[Reed Gray]

This is some thing I am still figuring out. If the blade is perfectly straight across, you will get small lines from the edge of the blade. They can be seen and felt. At first I was putting a bit more pressure on the edges with the coarser stones, 1000 grit and up. That does seem to help. If you have a scrub plane, you kind of have to eyeball that much of a curve. I am working my way up the grits to see what works best. Generally, I just apply extra pressure on each outside of the blade for maybe 10 strokes on the 8000 grit stone. That seems to do the job. Well, at least I am leaving fewer marks.... Just about anyone who covers plane blade sharpening will cover this topic. Rob Cosman, Stumpy Nubs, Matt Estlea, Wood by Wright, and many others. They all do it slightly differently. As always, it takes some experimenting to find out what works for you. Biggest problem for me seems to be making sure the blade is perfectly square to the throat opening.

robo hippy

[Jimmy Harris]

Are you wanting to just round off the edges, or put a radius across the whole blade edge? Because if you're wanting to put a radius on the blade, like you would with a scrub or fore plane, then I'd find myself a grinder. The amount of work involved with that, and the difficulty in keeping the bevel and radius accurate, would be nigh impossible for all but the most skilled and patient among us. Even doing it on a grinder isn't easy, but it definitely takes the time and skill requirements down to something most mortals can deal with. Doing it by hand would require a figure 8 pattern or side to side roll pattern, which is difficult enough for just sharpening an iron. Trying to grind the iron to a radius from straight doing that would be some level of hell.

If you're just looking to round the edges so they don't leave tracks, I just put my index finger on the corner that I want to round off and push down on that corner, and then rotate the iron at an angle so that that corner I'm rounding is leading as I sharpen the iron. In other words, the iron is twisted diagonally to the direction I'm sharpening, instead of perpendicular. Then flip it around and do the same to the other corner. Keep the z-axis angle of the blade the same as normal so you maintain a constant bevel, and the increased pressure from your finger will slightly round the corners, as they'll see more wear from your stones. Since you're not removing a ton of material, it's pretty easy to do by hand. I usually only do this with the coarse grit, as it shouldn't be cutting into the wood, but just shy of it.

[Tom Trees]

A tip, to which I'm highly thankful to David W for, as I likely never woulda found out otherwise,
is a method for getting the camber perfectly balanced, since I choose to use the cap iron like anyone should for a panel plane or smoother,
as it's rarer to find the few examples of timber species what doesn't benefit from that, that might be personal for some,
I digress only to mention the camber must be very even and small to make it work.

Anyway, David's term "directed pressure" is more than misleading for what he means by that.
It sorta reads like leaning, and if skip read, might well seem like fingers close to the edge is describing what you might have seen, from say Cosman's tight and close grip for instance.

This isn't what David mentioned, as there's NOT much tipping involved if any...
The objective is to get each end symmetrical, which might take a go or two, to attain this Goldilocks camber.
David mentioned having a finger "on the money" and getting fingers dirty if need be (the reason I wouldn't have found for myself)
i.e nearly pressing on the stone, if yer still thinking Cosman distance

Much the same thing as lapping a card scraper with splayed fingers, where you place them, is where the material will be removed from.
This is much the same thing as with the corners of the plane iron.

Difficult to find a term for that, as near everything might come across as suggesting leaning or tipping.
Hope that helps, plenty of sharpening debates crop up often, but very little of them are actually concerning that aspect.

If to add anything onto this, is to make note of the position of the plane iron on the stone, and that it will work nicely when it's being honed
in much the same position as it would be in a honing guide, i.e in-line with the stone,
as not much happens doing this method if the iron is skewed.

That tip has saved me much effort, as everything else gives me variable results at best.

Good luck
Tom

[John Kananis]

I use a figure 8 motion when sharpening. When I want to keep edges completely square, I keep finger pressure in the middle of the blade. If I want the corners to ease off, I keep finger pressure on the outside of the blade.

[Warren Mickley]

In general, the stone gets a bit dished and naturally creates a slight camber on the blade. I have sharpened freehand for over sixty years and rarely flatten a stone.

For my smoothing plane and jointer plane, I am usually trying to limit the amount of camber, so I let the iron overhang the side of the stone. That concentrates the sharpening on the center of the iron, to keep it a small camber. It also wears the edges of the stone to help keep the stone flat. Managing the stone.

For a jack plane , I usually want more camber than the stone would naturally give. I let the iron cut only on one side or the other. You don't have to lift up or lean the iron very much, just see that the cutting is toward the edge. Again you are trying to manage the camber and maintain flatness of stone by how you sharpen.

I have seen bloggers promoting a rather extreme camber on the iron for rough work. Most of these people don't actually plane boards by hand unless it is for YouTube. In practice the camber is greater than a smoothing plane, but still rather subtle. You want the camber such that the corners don't dig in, but not much more.

[Rafael Herrera]

A perfectly straight edge is very difficult to achieve if one sharpens free hand, the tendency is for the iron to camber ever so slightly.

A straight edge on a smoother or a trying plane will leave track marks if your shavings are thick enough.

You want the ends of the blade to gradually stop cutting so no tracks are left behind. I've tried two methods to achieve that when sharpening: one method is to lift the blade and round off the blade corners, the second method is what Tom above says David recommended, "directed pressure". That is, without lifting the iron, apply more pressure on the corners of the iron to wear those ends a bit more than the center.

You don't say, but for what purpose are you asking about cambers? The pronounced camber used in jack/fore planes and to a lesser extent trying planes is not quite the same as what you need for a smoother.

[Mark Rainey]

A perfectly straight edge is very difficult to achieve if one sharpens free hand, the tendency is for the iron to camber ever so slightly.

Rafael, I have had never had free hand sharpening accidentally result in a camber that is of any use.

You don't say, but for what purpose are you asking about cambers? The pronounced camber used in jack/fore planes and to a lesser extent trying planes is not quite the same as what you need for a smoother.

After using hand planes for 20 years I am thinking that mastering camber is essential for full use - jack planes, smoothers, etc. The pressure at the ends does not give
me much, and does not give me a gentle curve. Warren, you are lucky to have a gently dished stone, but I do not. In that case do you recommend David Weaver's method as Tom describes above?

[Richard Coers]

There was a very early woodturning sharpening fixture that went all the way to the floor. You pivot it from side to side to grind a shallow arc on a scraper. I did the same thing to camber a plane blade. The length of the arm dictates the arc you want. I use a 1/2" dowel and a block of wood to hold the plane blade. If you put the pivot on the centerline of the wheel, it does a wonderful job.

[Warren Mickley]

After using hand planes for 20 years I am thinking that mastering camber is essential for full use - jack planes, smoothers, etc. The pressure at the ends does not give
me much, and does not give me a gentle curve. Warren, you are lucky to have a gently dished stone, but I do not. In that case do you recommend David Weaver's method as Tom describes above?

I am not sure that I do things differently than David. I gave a case where I am trying to obtain less camber and one where I am trying for more camber.

If you sharpen a cambered iron, you don't really need to lift it up, just see where on the edge it is cutting and make a small adjustment if needed. If you use the same small number of planes all the time, you remember which irons need more or less camber and gradually effect a change.

[steven c newman]

So...go watch the The Woodwright's Shop episode called "Hand Plane Essentials"

As they will show exactly HOW to camber the iron. BTW, I looked in the bottom of a certain Tool Chest...
Road Trip, The A Chest.JPG
And that same Stanley No. 5 was indeed sitting there...
Road Trip, Lost Art Press building.JPG
Building where that tool chest is located...and is still in use by this fellow...
Road Trip, C. Schwarz at work.JPG

[Tom Trees]

Here's two threads from the horses mouth
https://www.ukworkshop.co.uk/threads.../#post-1396126

https://www.ukworkshop.co.uk/threads...6#post-1587974

I didn't recall it was from a video of his, so it's one from before 2020, should be still there I would hope.

Tom

[Tom M King]

You can watch the amount of swarf created where you want to take more metal off, and it's a pretty good indicator once you get a feel for it. I keep a pair of block planes without camber, and a pair with. The only bench plane I have without camber is a no. 8 as I just use it on big edges but none that are as wide as the blade. The others all vary. I keep a number of no. 3's and 4's that match cambered finish plane tracks in old houses I've worked on. I don't own a single plane with only turned up corners and never saw indications of such in old work.

These are new shutters and steps on old museum houses. The depth of camber tracks and widths match other old smoothing planed surfaces in those houses. You can't see it without a strong raking light, in both these cases by the Sun. This type of work is really forgery, and it's a poor forgery with modern machined surfaces.

[Jim Koepke]

Rafael mentioned something pertinent to the subject:

A straight edge on a smoother or a trying plane will leave track marks if your shavings are thick enough.

When smoothing, a very light shaving will help to avoid tracks.

With a very light shaving if one wants to camber the blade, a stroke or two to the outside edge of the blade will be enough.

Here is an old post from a dozen years ago (and resurrected three years ago) on one method to camber a blade

https://sawmillcreek.org/showthread.php?158373

jtk