Mechanical feedthroughs transmit mechanical motion through the walls of a vacuum system. Both linear and rotary mechanical feedthroughs are included in this grouping.  Mechanical feedthroughs can be a combination of linear and rotary types, with separate drives for each. Typically, feedthroughs are rated for a maximum vacuum level.

There are several different types of mechanical feedthroughs. A linear mechanical feedthrough is a device for transmitting linear mechanical motion through the walls of a vacuum system. A rotary mechanical feed through is a device for transmitting rotational mechanical motion through the walls of a vacuum system. A linear/rotary mechanical feedthrough is a device for transmitting both linear and rotational mechanical motion through the walls of a vacuum system.

Among the performance parameters to be selected when specifying mechanical feedthroughs is mounting diameter. Mounting diameter is the diameter of the hole needed for mounting the feedthrough. Another important parameter is the vacuum rating. This is the maximum vacuum that mechanical feedthroughs can maintain. Another important parameter is the temperature range. This is the temperature range in which the feedthrough is designed to function. Another important selection criterion is the shaft diameter. This is the diameter of the actuating shaft used in the feedthrough. Another important consideration is linear performance. This includes stroke, which is the distance of one full shaft extension for a linear feedthrough. Linear force, another important parameter, is the maximum force the linear feedthrough can exert on a load. 

For rotary and linear/rotary mechanical feedthroughs, rotary performance must be considered in making a selection. Among rotary performance considerations are maximum torque and maximum speed. Maximum torque is the maximum torque the rotary feedthrough can exert on a load. Maximum speed is the maximum rotational speed of the rotary feedthrough. 

Another very important consideration in specifying mechanical feedthroughs is the mounting style. A flange mount mechanical feedthrough has a flange for mounting. A threaded mount mechanical feedthrough has threads for screw mounting. A nut mount mechanical feedthrough is placed through a hole and nut mounted. In addition, there may be additional specialized or proprietary mounting types from which to choose.