Jack Plane Vs Smoothing Plane

Comparing smoothing plane and jack plane functions and features.

Both jack plan es and smoothing planes are necessary tools for woodworkers. Besides, both require muscle power to enable and force the cutting blade over the stock’s surface to remove material off the wood surface.

A quick glance at these two hand planes would make you think they are almost identical. Yet, upon closer scrutiny, you will quickly notice the remarkable difference between these two hand planes. In this post, you will learn about the differences in their functionality, blade shape, size, plane frog, camber, and mouth opening.

To understand the difference between these two hand planes, you need to understand what the jack and smoothing planes are. You can use the jackplane for dressing down timber to the correct size to prepare it for edge jointing or truing. 

Jack Plane

Besides, if you have rough stock, you can use the jack plane to get the wood to the correct size. Since the jack plane is quite versatile, it has become the most used bench plane in woodworking.

The jack plane has a long body capable of flattening stock. It gets operated with both hands and comes with an adjusting nut to adjust the cutting depth of the plane. Moreover, it is best used for removing wood layers along the board’s grain and for rough works. Plus, you can use it for straightening surfaces and reducing thickness.

Smoothing Plane

On the other hand, the smoothing plane is the last hand plane you would use on the wood surface, allowing you to remove very fine shavings, leaving the wood with a smooth finish. Besides, if you use it well, you can produce a finish that surpasses or equals those sanded surfaces. The smoothing plane is short compared to the jack plane. Its length usually ranges from 5-1/2″ to 10.”

The smoothing plane gets also referred to as a smoother plane, and as the jack plane, it is also commonly used in woodworking. It also has a blade set angled at 45° to 50°, allowing it to make fine shavings when you push it along the wood’s grain.

The Main Differences Between Jack Plane & Smoothing Plane

The jack and smoothing planes may look the same to inexperienced eyes. But upon a closer look and quick use of each of these hand planers, you will see the main differences between the two. Below is a rundown of the significant differences between these two hand planes:

Plane Size

Smoothing Plane Size: The number 4 smoothing plane is the most used smoothing plane size. Its size, including a sole length, is 9 “-10.” Its smoothing plane iron has a width from 1″ to 2.” You will notice that the smoothing plane has a very balanced sole length and cutter width, which is critical to smoothing woodwork parts and furniture. Besides, the smoothing plane’s number 4 gets widely used for making cabinets. 

The smoothing plane is slightly smaller in size compared to the jack plane. The numbers 1 and 2 hand planes are 5-1/2″ and 7″ in length. You can’t use these two for smoothing tasks because they are small. Hence, they often get referred to as kid’s bench planes. 

However, the number 3 smoothing plane is perfect for smoothing small components or parts like mullions, narrow rails, and stiles. You can also use it to remove tear-outs on large boards. Nevertheless, its size is narrow and short. 

Jack Plane Size: On the other hand, the jack plane comes in many sizes that you can set up well for finer dimensions. The numbers 5 and 3 jack planes are the most used. Number 5 is not expensive, and you can use it for scrub works. You can also use the jack plane for aggressive smoothing results. 

The Number 5 jack plane has a 14″ sole and 2″ cutting width. You can use it for both finishing and rough tasks. Besides, it features an iron heavily cambered for dressing down stock. You will find this jack plane very useful in most woodworking projects.       

Blade’s Shapes

Another distinct difference between these two hand planes lies in their blade shapes. The smoothing plane comes with a slightly cambered sharp blade. Hence, it will help sharpen this blade before using it. Using water stone, you can sharpen its blade, and its blade’s sharpness is crucial to a smooth finish. 

Smoothing Plane’s Blade: Since it has a cambered-shaped blade, you can work this smoothing plane on minimal curves, which can be hard to see due to overlapped cuts. Nevertheless, it will give you the smoothest finish afterward. The 70mm is the recommended size of its blade. 

Jack Plane’s Blade: On the other hand, the jack plane’s blade has a rounded cutting edge which gets dulled and honed. Hence, you need not fuss about sharpening its blade before using it. Its blade got a 1″ to 2″ cutter width, angled at 45°. 

It is crucial to consider the cutting width because the resulting wood surface’s flatness will depend on it. Besides, it determines the amount of work you need to put in to achieve your desired results. 

Wider planes, of course, can make more expansive flat surfaces, but it usually consumes much time. Narrower cutting width makes thinner flat surfaces, but they work more quickly. Plus, with its rounded cutting edge, the jack plane can prevent the splitting and cracking of wood.

Planes Frog

Planes frog is quite helpful in doing away with scrapers. The plane frog’s angle has a direct effect on its functionality. The most popular frog angles for woodworking include 45° and 50°. The smoothing plane comes with smooth edges that enable you to achieve a smooth finish. Its iron doesn’t come with sharp and rough edges like that of the jack plane. For this reason, the smoothing plane specializes in providing smooth surface. 

Jack plane’s Frog: The jack plane, of course, can be good for smoothing. Yet, it can never be better than the smoothing plane because of its shave’s teeth-shaped edges. 

Smoothing Plane’s Frog: The number 4 smoothing plane comes with a frog angle of 50° that can lessen curly wood tearing. On the other hand, the jack plane comes with tooth-shaped edges that bite into the wood’s surface. The Number 5 Jack planes frog likewise comes with a 45° angle that allows this plane to glide effortlessly on the wood surface.

Mouth Opening

Mouth opening refers to the gap between the plane and the cutting edge. Hand planes with smaller openings can make thinner shavings. Moreover, the mouth opening of hand planers differs from one type to another. 

Smoothing Plane’s Mouth: The smoothing plane, for example, comes with a small mouth opening because it wants to produce thin shavings. With a small mouth opening, the smoothing plane can make less tear-off. 

But when you engage in heavy rough smoothing jobs, the mouth opening should be wider to enable the smoothing plane to avoid choking and clogging the smoothing plane. But if you deal with a non-rough surface with minimal defects, it will be best to set the mouth opening to small for reduced tear-out. 

Jack Plane’s Mouth: On the other hand, the jack plane allows for 1/16″ adjustments for more delicate and general works. You should set the mouth opening relative to the shaving’s thickness. Since the shaving thickness of the jack plane is large, you should set its mouth opening wider. 

You can control the loosening of the jack plane’s mouth opening by loosening its front button and turning the lever that adjusts the twisted plate at the front of the hand plane.

Camber

Another factor wherein these two hand planes differ lies in their camber. Cambered iron helps in light shaving and smoothens the wood. Besides, camber can remove materials quickly. 

Smoothing Plane’s Camber: The smoothing plane features a minimal camber because you will use it only to smoothen wood. Similarly, the irons of the smoothing plane are also straight and come with softened corned, which is helpful as true camber. 

Since the camber has a thin maximum projection, shavings become more transparent. Besides, the camber’s corners get nicked to prevent the wood surface’s tacks. 

Jack plane’s Camber: On the other hand, the camber of the jack plane is efficient and powerful when smoothing the surface of the wood. Hence, you will need some irons to achieve the full functionality of your jack plane. You should use a heavily cambered iron to make deep, narrow scoops out of the wood piece. 

Meanwhile, a less cambered one will do a similar function by smoothing the wood surface. Besides, you can insert another iron between to set the last iron sans any camber or a little camber. You can also slightly loosen the edges. 

Can Jack Plane Function as Smoothing Plane?

You might be asking why it is not advisable to use a jack plane as a smoothing plane when it can also smooth wood. Well, contrariwise, you can make the jack plane works like the smoothing plane. Yet, it can never really reproduce the smoothness that the smoothing plane can render to the wood. I mean the jack plane is not the perfect hand plane for smoothing workpieces. The smoothing process for workpieces is better left to the smoothing plane. 

The smoothing plane, of course, is designed for smoothing wood pieces. It is a specialized tool for this purpose. As such, it will be best to utilize this tool if you want a fantastic finish. 

You can just leave the jack plane for works that include dressing down the timber to prepare it. Besides, you might damage the work piece if you are adamant about using a jack plane for smoothing. 

Conclusion

Although there are different ways to smoothen the wood surface, you can never play down the value of smoothing and jack planes. But if you got all the powerful smoothing toys at hand, you probably would not touch the jack plane or the smoothing plane. In fact, I have a friend who got an array of jack planes and smoothing planes he hasn’t touched yet after inheriting them from his father.  

But indeed, there will come a time when you need to go manual when planing your woodworking. When that time comes, you can pull out your jack plane or smoothing plane from your storage cabinets and begin a muscle workout using these old reliable hand planes.

Leave a Comment