Show me your plane irons

[Lasse Hilbrandt]

How you round the corners to make a smooth transision between the passes.

[Patrick Chase]

How you round the corners to make a smooth transision between the passes.

That's going to be really hard to see in a picture unless there's a straightedge right next to it (I'll shoot one of mine later tonight when I'm off kid duty). For a smoothing plane the amount of camber is on the same order as the shaving thickness, so a few mils for a smoother. The geometric distortion of the camera is likely to be larger than that.

[Jim Koepke]

Here is a seven year old thread on a cambered blade of mine:

https://sawmillcreek.org/showthread.php?158373-My-Camber-Blade-Round-Tuit-Finally-Came&highlight=cambered

With the larger planes there isn't much worry about tracks. Take them down with the next plane and finish them off with a smoother.

A smoother without camber or a very slight camber will be able to smooth out tracks from the planes going before it. When it is time for the final passes set a sharp blade in a smoother to as light a cut as it can make. With just a little skill one can leave a track free surface shimmering surface.

jtk

[Lasse Hilbrandt]

Thanks!

Peter Sellers is promoting a very pronounced rounding of the corners, thats why I ask if you do the same?

[Mike Kreinhop]

Here's a video from Matt Estlea showing how to make a subtle camber on a plane iron.


https://www.youtube.com/watch?v=vtCAbP_B4as

[Derek Cohen]

He is such a beginner. Most on this forum can teach him a lot.

Incidentally, he is simply repeating what David Charlesworth taught 15 or more years ago. Look at David's videos for the finer details in this regard.

Regards from Perth

Derek

[Tom M King]

I have one of each bench plane, and multiples of some. None have rounded corners, but every one has some amount of camber for a particular use. The cambers are all rounded with the most depth in the middle, going to nothing at the edges for the thickness of shaving a particular camber is designed for. Rounded corners never made any kind of sense to me. I guess if you're going to sand anyway, it doesn't make a lot of difference though.

[Derek Cohen]

Ditto for Tom.

I do not round the corners of the blades. Each has a camber that suits the purpose of the plane.

Regards from Perth

Derek

[Brian Holcombe]

Rounding corners does not stop plane tracks, camber does though.

[brian zawatsky]

I round the corners of the iron on my smoother only, and only the last 1/16” or so of the width gets rounded. I like to grind my smoother irons flat and relieving the corners does help keep from getting tracks. I could never understand putting camber on an iron that you want to produce a smooth flat surface. My jack has camber, and try is a bit flatter than the jack but still cambered. Smoothers are flat with knocked-off corners.
Keeping the lateral adjustment of the iron as close to perfect as possible is necessary with this grind however.

[Patrick Chase]

Peter Sellers is promoting a very pronounced rounding of the corners, thats why I ask if you do the same?

Did he communicate that through a ouija board? (Peter Sellers has been dead for close to 40 years).

If it's Paul Sellers of whom you speak, then I'm going to get my popcorn and enjoy the show.

[Brian Holcombe]

A jack would normally have considerable camber, where on a smoother I relieve the edge via camber until the tracks disappear with a light shaving. Then, when I take shavings I take passes one next to another. The second round of passes is staggered by 1/2 width of the plane. The result is perfectly flat without visible or tangible scallops.

[Patrick Chase]

Rounding corners does not stop plane tracks, camber does though.


I round the corners of the iron on my smoother only, and only the last 1/16” or so of the width gets rounded. I like to grind my smoother irons flat and relieving the corners does help keep from getting tracks

I think that a lot depends on your standards for what constitutes "tracks". If we define "tracking" as "surface flatness deviation along the axis perpendicular to the planing direction" then planing always leaves tracks to some degree. The only possible exception is when the work is narrower than the plane such that you can work it in one pass. Even gradually cambered irons leave a very small amount of scalloping, which can usually be detected by somebody who has a high-precision straightedge and knows what to look for.

A more practical definition is "streaks that are visible after finishing", and that depends on the finish (specifically gloss level), the lighting conditions (grazing vs broad), and how closely you look.

I find that I can detect the aftermath of "rounded corners" from a mile away. They do improve things a bit by getting rid of the "hard corner" at the bottom of the step from one pass to the next, but the transition still occurs far too quickly to be imperceptible to any but the most casual observer. Cambering works because it spreads height changes out over a wide area, and renders them much less perceptible.

[bridger berdel]

Curved plane edges are not all for the same reason, nor is the geometry figured the same way. A smoother iron is cambered about the thickness of the shaving. A scrub iron is curved to maximize depth of cut. Jacks and jointers have their own geometries. If we broaden the discussion beyond bench planes, molding planes have a whole 'nother world of sharpening parameters.


Fwiw, my smoothers have a curvature that is fairly even along the edge but a bit more rounded at the corners. This may be a sign of laziness on my part or an organic adaptation to a somewhat chaotic work environment or some other lame excuse, but that's just how I roll, dudes.

[John Schtrumpf]

Here are my jack, try (for my jack) and smoother blades (the smoother could use a tick more camber). I photographed them with the chip breaker on, so the edge is more apparent.

[Jim Koepke]

How you round the corners to make a smooth transision between the passes.

There are other details of a plane which will also affect the results. Of course my caveat is my experience is mostly with Bailey style planes and others of its ilk.

For smoothing a fairly flat sole is important. One of my planes had a sole which was slightly concave from toe to heel. Pressing down on it would get it to cut, but if the pressure was relieved it wouldn't stay in the cut on a light pass. With the blade adjusted enough to take a cut without pressure, it would pull deeper, dig in and chatter. A very slight concave sole can be very subtle and drive a person to drink if the problem isn't discovered.

Another plane had a slightly rounded sole from a poor lapping attempt. The blade would engage at the sides before touching the work in the center of the blade. Fortunately this was only a couple of thousandths of an inch off.

My #4-1/2 used to give me fits before doing a bit of fettling on the frog and working over the rest of the plane. It is about the worst plane in my fleet for the sole not being square to the sides. It also has one of the thinnest castings. It is a type 6 which all of mine seem to have lighter castings than the later types. My main problem with it was it would all of a sudden start to leave tracks on one side. It was a big slap to the forehead when it was finally corrected. All it took was about a 16th of a turn tighter on the lever cap screw.

For many thin shavings "are a waste of time and effort." This is true if you are trying to scrub plane and dimension a plank. When it comes to the final passes before a stain or finish a beautiful shine can be produced on the surface of many woods. Mostly for my use pulling a thin shaving when setting the blade is helpful in setting the lateral adjustment. It also is helpful in diagnosing the blade condition before starting on the work. Often my plane irons are sharpened before they are put on the shelf. Just as often they are not. Trying to remember if a plane was sharpened after a few days or even a week of not being in the shop is not going to happen. One of my plans in the past was short lived. Just before a plane was put away a shaving would be made. The shaving was stowed with the plane to show how it was set up and to be able to see the condition of the blade. This didn't work for me and was abandoned.

With all else considered, here is the back of a blade from one of my #4 type 6 planes:

380485

There may be a slight camber on this blade. If so, it isn't from an effort to do so, it is from the water stones being worn slightly more in the center.

Imagine my embarrassment when after thinking this back was flat, someone (if my memory is working it was Patrick Chase) pointed out the reflection of the over head lamp indicated there was a bit of curvature at the edge. It is also all scratchy looking.

The saving grace is it is the performance that really matters:

380486

This is one of the shavings made while setting the lateral adjustment. The micrometer has a ratcheting clutch to prevent compression of the item being measured. This indicates the shaving is a hair more than two - ten thousandths of an inch or a little more than five - thousandths of a millimeter.

A shaving has to be about half that again to get the folks at Kezu (is that correct) interested.

Can the eye see or the fingers feel such a small difference on the surface of a table?

jtk

[Bob Leistner]

http://ecemmerich.de/wp-content/uploads/E.C.E.-The-Tool-Catalog-2017.pdf Page 15 of ECE's catalog recommends rounding of the corners only for smoothers and try plane blades.

[Patrick Chase]

There are other details of a plane which will also affect the results.

Yeah, I've heard that rounding the corners only works if the iron has 2 degrees of clearance and has been honed to 250# ;-).



Imagine my embarrassment when after thinking this back was flat, someone (if my memory is working it was Patrick Chase) pointed out the reflection of the over head lamp indicated there was a bit of curvature at the edge.

In my defense I believe that was during one of the periodic flamewars about the ruler trick, and I pointed it out to illustrate that a lot of people who get good results with a perfectly flat back are actually dubbing a teeny bit to focus their polishing efforts at the edge.

[Jim Koepke]

In my defense I believe that was during one of the periodic flamewars about the ruler trick, and I pointed it out to illustrate that a lot of people who get good results with a perfectly flat back are actually dubbing a teeny bit to focus their polishing efforts at the edge.

My feeling about the ruler trick is it is another step that isn't necessary.

Of course it isn't necessary, it happens all by itself. :D

jtk