In setting up a shaker test, typically the stinger is slid into the shakers through-hole armature with the force transducer or impedance head attached to the end of the stinger. With the shaker collet loosened, the stinger can be extended in and out of the armature to obtain the desired length. Once this is done then the force gage or impedance head mounting pad can be affixed to the structure; the mounting pad is often attached using dental cement, two-part quick epoxy or a Loctite adhesive. Often a piece of foil adhesive tape is first adhered to protect the surface of the test article, with the mounting pad bonded to the tape.
If the alignment is correct, the shaker stinger will easily unthread from the force transducer or impedance head AND also thread right back in without any binding or difficulty whatsoever. This should be accomplished without the stinger putting side load onto the shaker armature, sliding easily within the chuck and collet assembly, which assures that the shaker and stinger are properly aligned.
At times there may be a threaded mating hole in the structure for mounting the force gage or impedance head and attaching the shaker. Alignment in these situations is much more difficult, requiring that the shaker and/or the test article be moved such that the fixed threaded hole places the stinger exactly in the correct position. The main point is that the shaker must be aligned such that the stinger can be very easily threaded in to the force gage or impedance head with no difficulty or binding whatsoever.