- Electric drive: characteristics and features
- Planer shaft device
- Sole device and planing settings
- Ergonomics and other features
In carpentry workshops, the electric plane sits proudly in the most honorable place, often in the company of others of its kind. There are several types of this tool, differing in ease of use, productivity and other technical characteristics..
Electric drive: characteristics and features
The source of torque in the electric plane is a universal collector-type electric motor, standard for most hand tools. Classic layout: in the rear part of the armature there is a current-collecting unit with a rolling bearing, in the front there is a fan impeller. True, the impeller itself is reinforced, has a casing and a complex aerodynamic shape, which is necessary for the intensive removal of a large volume of chips formed during operation.
The most specific unit of this tool is the transmission, which transfers rotation from the anchor to the planer shaft. In electric planers, either gear or poly-V belt transmission is used. The latter type of transmission is more profitable: due to the slipping of the belt along the pulley, the knives’ impacts on the material are compensated, thereby ensuring the safety of the engine and increasing the convenience of work. Another nuance is the fastening of the pulleys, which in most budget models is made by landing on the left and right threads. This is not very good: over time, aluminum pulleys are overtightened, often unevenly, which causes the belt to skew, wobble appears, besides, with further maintenance, unscrewing the pulley without damaging it is a serious problem. Therefore, a spline or key fit is much more profitable..
The drive power in electric planers has a practical minimum threshold of 600 W and can reach 2 kW. The powerful tool has an increased planing width, the amount of material removed is greater, while the weight and size of the body increase. However, unlike most tools, the increased weight of the planer is an additional plus: the massive tool withstands shock loads better and is easier to control during operation. The average rotation speed taken from the secondary pulley is 15-17 thousand rpm. With the gear ratio of the belt drive from 2.2 to 3, the armature itself rotates at a frequency of more than 30 thousand rpm, which means that the quality of the bearings must be very high.
Planer shaft device
The main working body of the electric planer has the form of an aluminum drum with several longitudinal slots of a trapezoidal profile, in which knives are attached. The drum can be solid or have cavities, that is, it can be made lightweight. On the one hand, this reduces the load on the engine during the start, accelerates reaching the rated speed and facilitates balancing, traces of which must be present on the end of the shaft. But, as mentioned, the increased inertia of the massive drum is good for absorbing shock loads..
As a rule, only two knives are placed on the planer shaft at diametrically opposite points. Some models have three knives, which helps to remove material in smaller portions and improves planing cleanliness. However, it must be remembered that replacement knives for planers are sold in pairs, which means that for one replacement you will have to purchase two sets at once. There are also planers with one knife, which have a slightly lower gear ratio to increase the shaft speed to 18–20 thousand rpm. In this case, a HSS knife is used, which is only suitable for finishing with low stock removal..
The planer shafts can vary in diameter within 40–65 mm. The larger the size, the more shallow the knife will cut in, which reduces the shock load on the edge and contributes to a cleaner cut. But it should be remembered that the angle of sharpening of knives differs depending on the size of the drum and sometimes difficulties arise in choosing the right consumables. The knives themselves are single and double-sided. The first type is allowed to sharpen as it becomes dull, while double-sided blades can be turned over, and after final wear, they can be replaced with new ones. The fastening of knives in almost all jigsaws is unified – a spacer block with three clamping screws and two gougeons for adjusting the depth and skew.
There are two subtle nuances regarding the planer shaft. The first is the type of bearings on which the shaft is fixed, it is better if these are needle-type sliding units for better resistance to radial shock loads. The second point is the presence of a protective casing at the ends of the shaft, which prevents damage to the power cord.
Sole device and planing settings
The sole of the planer consists of two parts: the rear one serves as the base of the engine and always remains stationary, the front one can be adjusted in height to change the planing depth. The sole should be made of durable aluminum that is not subject to deformation and abrasion. In the simplest case, both parts are milled separately, and then aligned on a common base, which does not provide a high level of alignment accuracy. Professional models undergo a final sanding assembly to ensure that the front and back of the sole are parallel.
Some planers have one or more longitudinal grooves on the front of the sole for chamfering. It is better if there are several such grooves: they have different depths, moreover, it is easier to chamfer with a groove offset to the edge on parts with steps, for example, on elements of a door frame. It is also desirable for the forefoot sole to have a streamlined nose to facilitate planing of close-knit flooring, where there may be a significant drop between adjacent boards..
The width of the sole should be less than that of the knives, without this it is impossible to use a plane to select a quarter. Also, to perform this operation, you will need a parallel stop and a cheek that limits the depth of the quarter. It is especially important that the engine is positioned high enough and the side plate of the body does not restrict the sampling depth.
The planing depth itself is regulated by the front handle: for most planers, the maximum removal rate is 3 mm, for the most powerful models it can reach 4.5–5 mm. In this regard, it is not necessary to choose especially, the difference lies only in the adjustment step, which can be from 0.1 to 0.5 mm.
Ergonomics and other features
In general, all planers have a typical design and differ only in minor design details. However, there are quite a few specific features regarding the ergonomics and arrangement of the tool assemblies..
For example, if the hole for ejection of chips is too narrow or poorly placed relative to the drum chamber, it will be impossible to work with the plane due to the constantly clogged nozzle. Among other features of the chip removal system, the collection bag device can be distinguished: it must necessarily have a bracket so that the fabric does not wrinkle or twist. In addition to the bag, the kit must include a branch pipe for connecting a vacuum cleaner, if one is planned to be used. Some models have the ability to change the direction of chip ejection, which can be very useful when machining large parts.
A special point is the shape of the handle, which should be streamlined and not have sharp edges so as not to cut into the palm. In this case, the main part of the body, on the contrary, must have several absolutely flat edges so that the tool can be stably placed on the floor without risking damaging the knives. By the way, some models have a folding stop on the sole or in the back, which allows you to put the tool with the sole on any surface, while the knives are guaranteed not to touch it.
Another specific feature is the shape and placement of the handle. If it is shifted closer to the back, it will be easier to press the back of the sole against the surface when slicing the edge of the part. If the handle is in the middle, there is a high probability that the tool will involuntarily tilt forward and blockage will form at the edge. On the other hand, an elongated rear sole can counteract this phenomenon. Also, the main handle can have an additional mushroom in the front part to hold the tool with two hands, because taking the front sole adjustment knob, there is a risk of knocking down the setting. Some planers are supplied with stands for stationary installation in an inverted position. To work in this mode, it is necessary to have a wide parallel stop and a protective pad that moves away when the workpiece approaches. A bracket is also required to block the trigger.