Tag-Archive for ◊ bevel-up plane design ◊

• Wednesday, July 31st, 2019
bevel-up planes

A few more points on this topic:

1. If you had a BU jack plane with a 20° bed, could you still use it on end grain? Sure. My Lie-Nielsen #9 “iron miter plane” has a bed of 20° and it works wonderfully on end grain, and so does my L-N shoulder plane with a bed of 18°. Perhaps this is so because resistance is indeed determined solely by the attack angle and not by the sharpening angle per se. 

2. This is not about block planes, which, of course, also happen to be bevel-up. It is about BU smoothing planes and, to a lesser extent BU jack planes. Incidentally, I suspect one reason for the popularity of 12°-bed block planes over 20°-bed models is that the former are more compact and thus easier to manipulate with one hand. 

3. This is not just a theoretical discussion. BU planes with 20-22° beds have been designed and are available from distinguished planemakers. Take a look at Karl Holtey’s #98 Smoother. Philip Marcou offers bevel-up smoothing and jack planes with 15° and 20° bed angles. [Drool, drool . . .] Though not it’s intended to be used as a smoothing plane, I’ve experimented with setting up my L-N #9 (20° bed) as a high-attack smoother. It works. 

So, what’s the point of these four posts? It is simply this: a good addition to the Lee Valley and Lie-Nielsen product lines would be, at the least, the option of a bevel-up smoothing plane with a 20-22° bed. (22° would suit me just fine.)

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• Tuesday, July 30th, 2019
bevel-up smoothing plane








Coming up: just a few more points.

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• Monday, July 22nd, 2019
bevel-up plane blades

In the previous post, I discussed how a 20-22° bed in a bevel-up smoothing plane can produce a wider range of useful attack angles without resorting to excessively high sharpening angles. The use of narrower sharpening angles has, in turn, several advantages:

1. Sharpening is easier. It is simply more difficult to get a good, sharp edge at, for example, 43° than 33°. It is also awkward to work at the higher angles, and the feedback from the surface of the stone is not as good. I think this is readily evident but some may disagree.  

2. Based on my experience, and I think most woodworkers would agree, a blade with a very steep secondary bevel dulls faster than one with a more usual, narrower bevel, all else being equal. 


Sidebar: how an edge dulls

The profile of the sharp edge of the blade ideally starts out as two straight surfaces meeting at a clean, sharp point. As the edge wears, steel is abraded away from the surfaces near the edge, and the original point becomes rounded over. The worn surfaces of the blade that approach the blunted edge can be thought of as “wear bevels.” Thanks to Brent Beach and Steve Elliot for their development and detailed study of these concepts.

For both bevel-up and bevel-down planes, the wear bevel on the top side of the blade (the side facing away from the wood) is wider than that on the bottom side, because it is the top (front) of the blade that bears the brunt of the collision with the wood. The bottom-side wear bevel, which is on the flat side of the blade in a BU plane, is nonetheless important.

Brent Beach explains the value of removing the lower wear bevel when sharpening to regain a truly sharp edge, to maintain proper clearance of the blade edge from the wood, and to avoid the need to apply undue pressure when planing. David Charlesworth’s Ruler Trick is thus particularly helpful for bevel-up plane blades.


3. A functionally sharp edge is preserved longer when the blade is sharpened at a narrower angle. This is consistent with point #2. Australian planemaker Terry Gordon explains this nicely in a recent article in Furniture and Cabinetmaking magazine (November 2018, Issue 276, pp. 48-50). It is best understood diagrammatically but the gist is that a skinnier edge retains useful sharpness longer by remaining narrow longer.

In summary, there are important advantages in sharpening and edge endurance when using the narrower sharpening angles permitted by a higher bed angle in bevel-up smoothing planes.

For example, if you want a 55° attack in your BU smoother, you’re better off being able to sharpen at 33° with a 22° bed (=55°) than having to sharpen at 43° with the 12° bed (=55°) in currently offered stock planes.

Coming up: still more issues. Can you tell that I’m building a case that I think L-N and L-V should hear?

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• Sunday, June 30th, 2019
bevel-up planes

Lee Valley and Lie-Nielsen both use a 12° bed for their bevel-up (BU) bench planes. At least for smoothing planes, I think there are better options. I addressed this issue in a 2010 post but now would like to add additional reasoning.

Let’s start with the issue of attack angle.

One of the advantages of BU planes is the attack angle (the angle between the wood and the leading surface of the blade) can be altered simply by changing the sharpening angle of the final microbevel. There is no need to change the frog and/or create a large back bevel (a large bevel on the normally flat side of the blade) as with a bevel-down plane. The attack angle is a key factor in how a plane functions, especially to control tear out. 

In a bevel-up plane with a 12° bed, to achieve a 50° attack angle, a good all-around angle for a smoother, the sharpening angle must be 38°. (Note that all of the sharpening angles in this discussion are only the final, steepest microbevel, which is what actually interacts with the wood.) A 55° attack, a good choice to manage most figured woods, would require a 43° sharpening angle. A 60° attack, which is about as steep as you can go before the plane acts more like a scraper but is nonetheless useful for difficult woods, requires a 48° sharpening!

Alternatively, let’s consider a 22° bed for the bevel-up smoothing plane. Much lower sharpening angles can be used. For example, a 33° sharpening angle yields a 55° attack, which is a nice setup with an A-2 blade. The 60° attack requires a still-manageable 38° sharpening. On the other hand, if you want a lower attack, you could sharpen at 28° or 30°, such as with an O-1 blade, to yield a 50-52° attack. If slightly lower attack angles suit you, a 20° bed is a good, versatile compromise.

So, a 20-22° bed angle in a bevel-up smoothing plane allows you to a create a good range of attack angles without the excessively high sharpening angles required with a 12° bed.

For a BU jack plane, the case for a steeper bed is less compelling, though still interesting. A 12° bed with a 33° sharpening – typical for an A-2 blade that would often be found in a jack – gives a 45° attack, which many woodworkers consider to be a good all-around choice for a jack. Still, a 15° bed would increase the versatility of the plane in creating slightly higher attack angles without having to increase the sharpening angle too much. 

To summarize the main point: a bevel-up smoothing plane with a 12° bed requires excessively high sharpening angles to achieve the very helpful range of attack angles that is one of the key advantages to this type of plane. 

Much more to come on this topic in upcoming posts. Those excessively high sharpening angles produce several disadvantages. Furthermore, the lower 12° bed is a disadvantage in itself, and actually lacks a traditionally-cited advantage.

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• Saturday, June 26th, 2010








