This gas cutting machine is a ST-37 metal cutting tool in a semi-automatic way using LPG and Oxygen gas materials. LPG gas is used with a composition of propane 99,5% and Isobutan 5%. In the process of cutting metal must pay attention to several parameters, namely: metal thickness, oxygen gas pressure and LPG gas and cutting speed. Before cutting down the metal, the preparation stage is done by conditioning the test equipment and work equipment used to collect test data. The method used in this research is to select the type of metal and cutting equipment then do the recording and taking test data. Further analysis and examination are carried out as follows: visual inspection of the results of cutting and flame shape, a better composition results from testing in accordance with applicable rules such as pressure, plate thickness and time of cutting. 99,5% and 0,5% LPG gas composition at gas working pressure: 0.2 kg / cm2; oxygen pressure: 2.5 kg / cm2, cutting distance of 2mm. The results of this test are overall in good condition and no defects occur.