The Friction Stir Lap Welding (FSLW) is an alternative to join aluminum sheets. The distortion and deflection of the FSLW results are very low because the joining process is in a solid state. FSLW can also be applied to joint materials that are difficult to weld when using conventional methods or joining techniques such as solder or rivet. Purpose of this experiment is to analyze the effect of high-speed tool rotation on micro Friction Stir Lap Welding (FSLW) to the shear load of the welds. This experiment uses different metal types of aluminum sheet A1100 with 0.4 mm thickness and A1050 aluminum sheet with 0.4 mm thickness. CNC Milling Emco type TU-3A is the equipment for this experiment with 33,000-rpm tool rotation. The parameters is traverse speed of tool (40, 60, 80 mm / min). The Pin diameter variations are 1.6 mm, 2.0 mm, and 2.4 mm. Moreover, variations on tool tilt angle are 2°, 3°, and 4°. Data analysis is using multi-variable, with 3 tests of parameters full-factorial. Mechanical shear strength of the welded specimen follows JIS standard (JIS.2201-1999). The highest tensile strength occurs at the smallest tilt angle of tool (2°).