Comparison FDB Maschinen Drilling 20 827257 vs FDB Maschinen Drilling 25 827258

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 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.

The size of the Morse taper chuck (see Chuck Type) that the drill is equipped with.

Morse tapers are available in several standard sizes. The most popular standard provides marking with the letters MK and a number — for example, MK2. The larger the number in the designation, the larger the diameter of the cone and, accordingly, the thicker the drills in which it is used. In modern drilling machines, chucks with sizes from MK1 to MK4 are usually used. But in fact, this parameter is necessary primarily for the selection of compatible drills.

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.

The nominal supply voltage required for the operation of the machine. When connected to a network (see "Power supply"), this parameter determines not only the voltage, but also the type of network used. In such cases, the options may be as follows:

- 230 V. Standard single-phase household networks; roughly speaking, such a machine can be plugged into a regular outlet. This option is not well suited for powerful electric motors, which is why the power of single-phase machines rarely exceeds 2000 watts. At the same time, 230 V networks are widespread almost everywhere, which makes it much easier to connect.

- 400 V. Three-phase power supply of high power, suitable for even the heaviest and most productive units; however, it is also found in relatively modest models, for which (in theory) 230 V would be enough. The latter is due to the fact that, for a number of reasons, a three-phase connection is more convenient for electric motors installed in machine tools: in particular, such networks can more easily withstand high loads (for example, when starting the engine, when the current is much higher than the working one). True, the ability to connect to 400 V is initially not available everywhere, and its organization may require electrical work, sometimes quite extensive.

If the specifications indicate a voltage lower than 230 V, this usually means that we are talking about a...battery-powered tool (see "Power Source"). The most common batteries are 18 and 25.2 V. In theory, high voltage is better suited for powerful batteries and, accordingly, machine tools; however, most often this parameter does not particularly affect the performance of the unit, and in practice, capacity data may be useful only in specific situations (for example, when looking for a charger or a replacement battery).