Comparison Einhell Expert TE-BD 750 E vs Optimum OPTIdrill B 23Pro (230 V) 3003231

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 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.

The dimensions of the base of the machine — the platform, thanks to which it is able to stand steadily on the floor or workbench. This indicator allows you to estimate how much free space is needed to accommodate the unit. More powerful, larger and, accordingly, heavier machines have a larger base diameter.

The largest diameter of holes that can be drilled in metal with this machine. At the same time, the characteristics give an indicator for a certain “average” (in terms of hardness, density, etc. metal), while in fact the characteristics of the material may be different; this must be taken into account when choosing. Nevertheless, the maximum drilling diameter is a fairly descriptive parameter that describes well the capabilities of the machine and the limitations on its use.

Note that regardless of the material, the larger the hole diameter, the higher the resistance that must be overcome during drilling, and the greater the engine power should be (see above). This means that powerful and heavy machines are required to efficiently drill large holes. So, when choosing, it doesn’t always make sense to chase after a “large-caliber” model — it can turn out to be unreasonably expensive, bulky and heavy.

It is also worth considering that the size of the cartridge (see above) is often larger than the maximum drilling diameter; however, it is still impossible to exceed the manufacturer's recommendations — in order to avoid overloading the tool.

— Reverse. The possibility of rotating the spindle in the opposite direction — to "unscrew" the drill from the material. The main function of this function is to free the tool stuck in the workpiece. In addition, reverse can be useful for some specific types of work, such as threading (in fact, almost all machines with reverse allow this use).

— Adjustment of frequency of rotation. In this case, the ability to smoothly change the speed of rotation of the spindle is implied. This allows you to fine-tune the speed much more precisely than by choosing one of the fixed speeds (see "Number of speeds"). In this case, both methods of adjustment can be provided in the same machine. Anyway, models with smooth adjustment are considered more advanced than units without it.

— Auto speed control. An automatic system that regulates the power supplied to the spindle depending on the load on the drill — in such a way that the rotation speed of the tool remains unchanged: at high loads, the power increases, at low loads it decreases. A constant rotation speed has a positive effect on both the quality of processing and the service life of the drills and the machine itself.

— Brushless motor. The brushless type electric motor does not have carbon brushes. Such units are much more complicated and more expensive than classic collector motors, but they have a number of important advantages over them. These are, in particular, high ef...ficiency, minimal heating during operation, durability, very low noise level, as well as an almost zero probability of sparks, which allows you to work safely in conditions of increased fire danger.

— Backlight. The presence in the machine of its own lighting system — in the form of a lamp aimed at the place of work. This function makes the unit independent of external lighting and allows you to work comfortably even in low light (up to complete darkness). And in the daytime, the light can be obscured by surrounding objects, or even by the machine itself; in this case, the backlight will also be useful.

— Laser marker. A laser marker that plays the role of a “target indicator”: a mark from it shows a point on the workpiece that the drill touches if it is lowered right now. This feature makes it much easier to point the tool at the desired point.

— Digital display. Own display, which can display various numbers and special characters. Usually this is a fairly simple screen for 3-4 digits, however, even such a screen is more informative than indicator lights. For example, the display can show the exact spindle speed; and in general, this function makes the management more convenient and intuitive.

— Coolant supply (coolant). A system that allows you to supply cutting fluid (coolant) to the place of work. This function is especially important in “heavy” work, with intensive processing of hard materials or delicate parts: by reducing heat and friction, coolant prevents deformation of workpieces, reduces the likelihood of defects and overall tool wear. In addition, the coolant can perform other special functions, such as anti-corrosion treatment. Note that the design of the supply system can be different — from the simplest tank above the spindle, from which coolant flows by gravity, to a separate pump with its own engine. This point before buying needs to be specified separately.