Comparison Einhell Blue BT-BD 701 vs Bosch PBD 40

A type of mechanism used to transfer rotation from a motor to a spindle.

- Belt. Transmission in the form of two or more pulleys connected by a belt(s). This is a fairly simple and at the same time functional design, quite suitable for entry-level and intermediate-level drilling machines. Of its shortcomings, it is worth noting the relatively poor suitability for high loads, as well as the fact that in order to switch the rotation speed (see "Number of speeds"), you usually have to rearrange the pulley (or the belt on the pulley).

- Gearbox. Machines equipped with a gearbox that reduces the spindle speed relative to the engine speed. Usually, the gearbox is based on a gear train, although other designs are possible. Anyway, such a mechanism is noticeably more complicated and more expensive than the belt drive described above, but it has a number of important advantages. The gearbox is better suited for transmitting large traction forces (due to design features). The presence of such a transmission is typical for advanced professional machines; in particular, it is standard for magnetic models (see "Type").

Rated power consumption of the machine. In this case, the total power consumption of the machine is indicated, which, as a rule, is equal to the power of the main engine responsible for rotating the spindle. The design may also include other motors - for example, for automatic feeding (see “Control”) or coolant pumping (see “Functions”) - they are also taken into account. The “gluttony” of such motors is relatively low for low-power machines, and the power of the main engine is one of the main characteristics for any machine: it determines the class of the unit and its general capabilities.

A more powerful motor allows you to drill at higher speeds (which reduces drilling time) and/or with higher torque (important for hard materials and large size drills/bits). Accordingly, the more powerful the machine, the more advanced, as a rule, it is, the more opportunities are available when working with it. The downside of this is that with increasing power, the dimensions, weight, price and, accordingly, energy consumption of the unit increase. Therefore, you need to choose based on this indicator taking into account the work for which the machine is purchased. So, for simple tasks (for example, a home workshop, where you plan to work only from time to time), a power of about 300 - 600 W is quite sufficient, for daily use in relatively “light” production (for example, furniture) - from 600 W to 1 kW, but for large metal parts, models fro...m 1 kW and above are recommended. We also note that, in addition to power, you should also focus on the maximum drilling size (see below).

The number of spindle speeds provided in the design of the machine.

The more speeds(with the same difference between the minimum and maximum number of revolutions, see below) — the more options the operator has to choose the operating mode and the more accurately the machine can be adjusted to the specifics of a particular task. However the specific values of fixed speeds, even for similar models, may be different; but most of the time the difference is not significant. In addition, multi-speed machines can be supplemented with smooth speed control (see "Functions"), which allows you to fine-tune the operating mode even more precisely.

Note that switching speeds can be done in different ways: in some models this is done literally at the touch of a button, in others you need to delve into the gearbox or belt drive.

The lowest spindle speed provided by the drilling machine.

Note that this parameter is indicated only for models with more than one speed (see "Number of speeds") and/or speed control (see "Functions") — that is, if the speed can be changed one way or another. See “Maximum number of revolutions"; here we note that the ability to work at low speeds in some cases is critical — for example, when threading. Accordingly, the lower the minimum speed, the better the machine is suitable for such work, other things being equal. The most "slow" modern models are able to rotate at a speed of 30 – 40 rpm.

The highest spindle speedprovided by a drilling machine; for models with only one speed, it is also indicated in this paragraph.

For the same engine power (see above), high RPM provides good performance, but torque is reduced; at lower speeds, on the contrary, the pulling force is increased, allowing you to “bite” into stubborn materials and make it easier to work with large diameter drills. Specific recommendations for optimal speeds depending on the type of material and drilling diameter can be found in special sources. At the same time, we note that a high-speed machine will not necessarily be “weak” in terms of torque — after all, many units allow you to reduce the rotation speed. However, efficient operation at high speeds still requires a fairly powerful engine, which accordingly affects the cost of the unit. Accordingly, it makes sense to look for a “fast” machine if you plan to work a lot with relatively soft materials, such as wood. But for metal, stone, etc. it is better to choose a relatively "slow" unit.

The largest spindle overhang provided in the design of the machine.

The overhang is the distance from the centre of the spindle to the supporting column. The maximum overhang corresponds to the greatest distance from the edge of the workpiece to the centre of the planned hole, at which this hole can be drilled on this machine; if this distance is greater than the overhang, the workpiece will rest against the support column and the drill simply will not reach the right place.

Note that this parameter is relevant only for vertical and radial machines (moreover, in the first case, the overhang is generally unchanged; see "Type"). But magnetic models do not have a limit on the size of the workpiece, so the overhang is not indicated for them at all.

The greatest distance that the spindle (quill) can lower from its original position. Theoretically, this is the maximum drilling depth that the machine can theoretically provide; in fact, this moment also depends on the size of the drill and the characteristics of the material. In addition, we note that manufacturers usually choose the stroke of the quill taking into account the general class and purpose of the machine; so this moment is rarely critical when choosing.

The diameter of the support column used in the machine. In fact, it is a purely reference indicator that does not play a special role in the normal use of the unit; data on the diameter of the column may be needed only for specific tasks such as repair and maintenance.

Dimensions of the base plate installed in the machine.

The base plate is the surface on which the workpiece is placed during operation. Accordingly, the larger this surface, the better this model is suitable for working with large parts (especially since the dimensions of the vise for the workpiece installed in many models depend on the size of the plate). However, usually manufacturers choose a base plate, focus on the overall level of the unit and approximately assuming the largest size of the workpiece with which it will be used. And magnetic machines are not equipped with a base plate at all (for more details, see "Type").

Note that for base plates, dimensions are usually indicated by the greatest length and width, and regardless of the shape. This means that, for example, a plate measuring 300x300 mm can be not only square, but also round.