###### Abstract
[22] studied the impact of the tool-nose radius on residual stress and flank wear over time at various cutting speeds and feed rates in the face turning of Inconel 718. [PERSON] et al. [23] studied the impact of cutting speed, feed rates, and depth of cut on tool life and surface quality in the turning of Ti(C7N3)/WC/TaC cement cutting tools. [PERSON] et al. [24] also made the comparison of three machine learning techniques for prediction of \(Ra\), cutting force (formula presented), and tool lifetime (\(T\)) during high speed turning. [PERSON] and [PERSON] [25] built an adaptive feedback linear control system to check the variation in cutting force signals to improve tool life. They discussed the use of the transfer function approach for improving mathematical modelling and adaptive control of the process dynamics of turning operations. [PERSON] et al. [26] performed turning experiments on Ti-6 Al-4V alloy under dry and high-pressure cooling conditions. The cutting inserts used were coated carbides and the surface quality (in terms of speed and feed) as well as tool wear (in terms of machining time) was discussed. [PERSON] et al. [27] calculated the Pareto frontier for surface roughness, \(Ra\), and the minimal machining time of a unit volume, \(T_{m}\), of a finished high-strength steel workpiece using an artificial neural network model that was subsequently used for determining the optimal cutting speed \(v_{c}\), feed rate, \(f\), and depth of cut, \(a_{p}\). [PERSON] [28] presented a tool condition monitoring study on the dry cutting process using observations of the tool life supported by the [PERSON] tool life model. [PERSON] et al. [29] investigated the condition of tools in terms of wear phenomenon and tool-life transition. The experiments consisted of turning operations on AISI D3 steel using a tool coated with a ceramic intermediate layer (TiCN/Al\({}_{2}\)O\({}_{3}\)/TiN). [PERSON] et al. [30] presented a study on the automatic prediction of tool life in turning operations. [PERSON] et al. [31] investigated the remaining useful tool life under different values of cutting parameters in the turning of Ti-MMC using the actual tool wear value of the worn tool as the input data. Maximum flank wear length at the transition point between the second and third state of tool wear was chosen as the failure criteria. All of the above studies have demonstrated that cutting speed has the highest influence on tool life. Most of these works applied CNC machines to select different spindle speeds that would achieve the required cutting speed for tools/workpieces of different diameters. However, commercial CNC machines are generally very costly and sometimes machine stability is compromised in an effort to reduce costs. It is worth recalling that many micro- and small-scale machining industries in various countries still utilize conventional machine tools with limited options for controlling spindle speed to produce machined components of different shapes and sizes. The massive size of conventional machines ensures the stability of the machining process. However, limited regulation of spindle speeds can only be obtained in conventional machines with belt drives and gear trains. Under such conditions, it is as difficult to achieve optimum cutting speeds for different diameters of workpiece/tool as it is to achieve the desired productivity. The upgrading of conventional machine tools that are still in good condition is a convenient way of improving productivity. The modernization of such machines can be done through improvements in the drive system and the use of a numerically controlled feed rate. Of course, the economic and technical feasibility of such a process should be carefully considered in each case. The use of an inverter to upgrade the drive is a particularly easy and cost-effective means of modernization [32].