Bevel up, bevel down: the facts (angles, thickness etc)

[MikeG.]

I'm pretty sure that bevel down planes have a bed angle of about 45 degrees. What is the theoretical angle they should have on the bevel? How thick were the traditional irons?

I have no idea at all about bevel up bench planes. What is their bedding angle? What is their bevel angle? How thick are the irons?

 

[lurker]

Blimey!
I never knew you were a £h!t stirrer, Mike.
Are you bored?

:wink:

 

[MikeG.]

No, I'm not interested in an argument. I just want the angles so I can draw them. Facts, and facts only. I've never used (or even touched) a bevel up plane, and want to work out what they are trying to achieve. No more, no less. I'm quite happy if someone could just direct me to a site where the facts are laid out (again, angles & thicknesses is all I'm interested in, not discussions of performance or whatever).

 

[Duncan A]

Posted by Custard years ago:
Bevel up hand planes are your friend with figured woods. I keep a few bevel up irons at different effective pitches; 50, 60, and even 75 degrees. The finish isn't as polished as you get from a normal 45 degree pitch, especially on softer hardwoods, but keep going up the scale and you'll eventually find a pitch that cures tear out. It's a lot harder work to plane at a high angle, but don't skew the plane to make it easier or tear out will return. You need to make sure there's sufficient slight camber to feather out the cut and also make sure the blade is really sharp right out to the edges or you're just asking for tear out at the blunt edge.

I have no idea what it's all about either!
Duncan

 

[Steve Maskery]

A bevel-down plane, like a trad No4, for instance, will have the frog at 45 deg (Common Pitch), and the blade will have two bevels, a grinding at 25 deg and a honing at 30. These angles are not critical, however, as they are for clearance only, the cutting angle is determined by the frog. If you change the frog for one at 50 deg, that is called York Pitch.
If you are just trying to model this up, I'd make the blade at 3 or 4mm, they vary from manufacturer to manufacturer anyway.

 

[nabs]

The answer to your question - at least for Lie Neilsen and Veritas BU bench planes (are there others?) - is that the bedding angle is 12 degrees and the blades are thick (just under 5 mm).

 

[MikeG.]

Thanks Steve, nabs.

 

[ED65]

I'm pretty sure that bevel down planes have a bed angle of about 45 degrees.

Depends if common pitch, York pitch or one of the others. But experience showed that 45° was the best compromise and that's why it was taken up when iron planes were first being designed. Most are bedded at 45° or close to it.

What is the theoretical angle they should have on the bevel?

It isn't really a theoretical thing but more about practical needs. And this should really be angles since the tradition was to grind at one angle and hone at another.

The angle at the edge needs to be high enough to provide clearance, low enough for acceptable durability (for the work at hand, so what's needed will vary with the wood being worked for any given steel hardness).

The tradition was a primary bevel of 25° (an average since it was usually curved) with the secondary bevel being created during honing by raising the blade "just a bit", so typically in the region of 30°. It can be made quite a bit steeper if needed, i.e. with softer steel, working harder wood or simply if the user wants to increase honing interval (back bevels help with this too by making the edge thicker, but at the cost of increased resistance).

How thick were the traditional irons?

Depends on the maker and whether it was a single-iron or double-iron plane, tapered on parallel, woodie or transitional or metal plane.

I have no idea at all about bevel up bench planes. What is their bedding angle? What is their bevel angle? How thick are the irons?

All three vary with the plane and the use it's intended for.

The commonest bevel-up planes are block planes since they've been produced in large numbers for over a century. Their beds were generally at one of three angles, with 12° the lowest and 20° the highest.

 

[MikeG.]

.......The commonest bevel-up planes are block planes since they've been produced in large numbers for over a century. Their beds were generally at one of three angles, with 12° the lowest and 20° the highest.

I know. I should have been clearer. I was more interested in the details of the modern bevel up bench planes.