Belt speed
Belt speed provided by the grinder. For more information about belt units, see "Type". In this paragraph, both one value and a range can be given — if the device has a speed control (see "Additionally — Speed regulator").
Other things being equal (primarily the same belt width), a higher speed has a positive effect on productivity. On the other hand, to ensure such a speed, a more powerful engine is needed, which accordingly affects the weight, price and energy consumption of the entire tool. In addition, the low belt speed contributes to accuracy: the chance of removing excess material is reduced. So it’s definitely worth looking specifically for a “fast” grinder only if it is to be used often and for large volumes of work. In other cases, a slower model may well be the best option. More detailed recommendations on this matter (including for different materials and types of work) can be found in special sources.
Noise level
Approximate noise level generated by the grinder during operation. Note that this indicator is quite approximate, because. actual "loudness" can vary markedly depending on the type and shape of the material being processed, the surface it is placed on, and other circumstances. In addition, different manufacturers may use different measurement methods. Nevertheless, this indicator makes it possible to assess how comfortable this or that model is in operation and whether special hearing protection is required.
The most “quiet” modern grinders give out about 65 dB — this is comparable to loud speech at a distance of 1 m; in the loudest, the noise level reaches 107 dB — this is the volume of an industrial workshop.
Weight
The total weight of the grinder; for battery models (see "Power Source"), usually, it is indicated without taking into account the battery.
This indicator has two meanings. On the one hand,
light weight has a positive effect on manoeuvrability and reduces fatigue during work — especially when processing vertical surfaces and ceilings, as well as in other situations where the tool has to be held on weight. On the other hand, for grinders with a vibrational principle of operation (see "Type"), used for processing horizontal surfaces, a significant weight is considered optimal: it allows the tool to fit closer to the material being processed, and also contributes to stability and retention. So when choosing such a model by weight, it is worth considering the features of its intended application.
