Lately it seems like I’m never going to make any more progress on the Arts and Crafts End Tables. A few weeks ago, I offered to make a gate for some friends and for now that is my priority. I may write a post about it later on – it will just depend on how willing I am to take the time to document the building process. Well, enough of that, on to the tool focus.
This week’s tool focus is on “bevel up” or “low angle” bench planes. The only bevel up plane I own is a Veritas #7 Jointer Plane. These planes are made in all sizes and have similar parts. First, we should look at why the planes are called bevel up or low angle planes. The answer is obvious – the iron is inserted into the plane body so that the beveled edge faces up. In a traditional hand plane, the bevel faces down and the blade sits at a 45° (typically) angle to the sole of the plane. Because the bevel faces downward, the angle where the iron meets the wood it is cutting is 45° as well (since the flat back of the iron is what meets the wood).
Bevel up planes are also called low angle planes because the bedding angle of the iron is 12° instead of 45°. With an iron sharpened with a 25° bevel, this makes the effective cutting angle of the iron 37° instead of 45° with a bevel down plane. This lower angle is more effective at cutting end grain. The real advantage of the bevel up planes is that you can change the nature of the plane by changing the angle the iron is sharpened at. If the plane is sharpened to 33°, the effective cutting angle is 45° – the same as a traditional plane. If you sharpen the blade to 43°, the effective angle is 55° also called “York Pitch”, which provides more of a scraping action that doesn’t tear out figured woods (where the grain of the wood changes radically and creates dramatic patterns in the surface) which are difficult to plane with a standard 45° plane. So, with a collection of irons sharpened to different angles, the bevel up plane can tackle a number of different jobs. To do this with a bevel down plane, you either have to put a second bevel on the back of the plane iron (called a “back bevel”, originally enough) or invest in a replacement frog that has a different bedding angle.
The bevel up planes are much simpler than their bevel down brothers. Most significantly, there is no chip breaker, only the iron and the cap iron. The Veritas line of planes also have a simplified adjustment system. These planes use what is known as a Norris style adjuster (the brass knob next to the rear handle of the plane). This adjuster has a screw that adjusts the depth of cut and also moves side to side to adjust the lateral position of the iron.
Also, adjusting the mouth of the plane is different than with a bevel down plane. In the last post, I described how the frog of a bevel down plane must be loosened and adjusted with a screw to open or close the mouth of the plane. In the Veritas line of bevel up planes, a section of the plane’s sole is adjustable to open or close the mouth (see the picture below). This is adjusted by loosen a thumbscrew (or the front knob in smaller planes) and then adjusting a screw that stops the mouth from closing more than is wanted.
Other than the methods of adjustment, bevel up planes work the same way as their bevel down brothers – with one minor exception that may not be obvious. If you choose to use a cambered iron (and I think you should with very few exceptions) the camber on a low angle plane has to be more severe than on a higher angle plane. The reason is that the low bed angle tends to have a flattening effect on angle that the iron meets the wood. So, a more pronounced camber or curve is necessary to compensate.
That brings us to the end of the discussion on bevel up planes. This is a difficult topic to cover succinctly, so, if you have any questions, please post them in a comment below. Next time, I will cover how jointer or try planes are used to flatten and square a board. Til next time…