SMC are small connectors used in testing equipment, and end item products.
DO NOT use plier,adjustable wrench, fixed wrench as you will not known when to stop tightening.
USE a SMC torque wrench, this will tighten to the correct torque.
SMC torque wrench should be calibrated for torque value.
Excessive tightening will damage the equipment’s connector and your connector.
Under tightening will lead to a poor connection (losses and emission) and reduced spec from the SMC form factor.
Consider the following SMC Torque Wrench: http://www.pasternack.com/product-PRESET-TORQUE-WRENCH-FOR-SMC-PE5011-2-71221.html
from Pasternack Enterprises www.pasternack.com
SMA connector are also available at Pasternack