A heat adjustment mechanism for a stud welding tool comprises an adjustment knob comprising adjustment ribs, a solenoid sleeve that moveably engages the adjustment knob, and that receives a solenoid, wherein the solenoid is configured to engage a fastener, and the solenoid is connected to the solenoid sleeve by the fastener, a clutch comprising adjustment ribs that engage the adjustment ribs on the adjustment knob, and a clutch spring that exerts force on the clutch. A weld heat setting adjustment may be made by solenoid movement of from about 0.15 mm to about 0.30 mm.