Low angle versus Bench Jack Plane

[John Stan]

Hi folks,


Happy New Year, I am looking to flatten some 5/4 x 16 inch x 8 FT book matched Cherry boards. Was thinking about using this as an excuse to get a jack plane. Unfortunately, I am confused about the functional diffences between the Low Angle Jack and the Bench Jack plane. I realize the angle is different and the LA is bevel up versus bevel down. That said, I am just not sure of the impact of these differences on the types of things I can do with the plane. Is one of the planes more versatile than the other? What are the advantages of the LA over the Bench type and vice versa.

For reference, a LN Low Angle Jointer, a LN 4 1/2 smoother, and a Lee Valley LA Block.



Thanks in advance,
John

[Hank Knight]

John,

You will probably get a lot of opinions in response to your question. I'll start by giving you mine.

Low angle jacks are more versitile than standard jack planes for two reasons: (1) the mouths on the new LA jacks are adjustable so you can set them for rank cuts or fine cuts easily (actually you can adjust the mouth on a standard jack by moving the frog, but it's a pain and not something you would do "on the fly", so to speak); and (2) you can change cutting angle on the LA jacks by changing the blade's bevel angle. This gives you the capability of changing the cutting geometry to handle different kinds of wood. For difficult-to-plane woods with high figure or interlocked grain that are prone to tear-out, you want a high angle of attack; for less figured woods and for end grain, you want a low cutting angle. Many low-angle jack owners keep an extra blade or two on hand ground with different cutting angles, so changing the cutting geometry is as simple as changing the blade. With standard bevel-down bench planes, the cutting angle is established by the angle of the frog and cannot easily be changed. There are ways to increase the cutting angle of a bevel-down iron, but they are complicated and require re-grinding the iron with a back bevel which has to be removed to return the plane to regular use. Moreover, you can't reduce the angle of attack below the angle set by the frog so you can't make a low-angle plane out of a standard #5.

I have and use both a standard jack plane and a low angle jack plane. I keep the standard jack set up for rough work and the LA jack set up for fine work. I have an extra blade for the LA jack ground with a high cuting angle for those tricky jobs. I like both planes; but if I could have only one in my shop, it would be the low angle jack because it can do it all. The standard jack can't.

Hope this helps.

Happy New Year.

Hank

[Marcus Ward]

Many low-angle jack owners keep an extra blade or two on hand ground with different cutting angles, so changing the cutting geometry is as simple as changing the blade. With standard bevel-down bench planes, the cutting angle is established by the angle of the frog and cannot easily be changed. There are ways to increase the cutting angle of a bevel-down iron, but they are complicated and require re-grinding the iron with a back bevel which has to be removed to return the plane to regular use.

You can just keep an extra blade around with the regular angle jack plane for a higher angle as well, it's not only an option with a low angle plane.

Also I agree a low angle jack is probably more versatile, although a heck of a lot more expensive.

This is discussed in great detail about once a week, searching through the archives will probably net a ton of responses.