The Contact block

 
The contact block or contact arrangement like the pivot comes in many shapes and sizes, some are very complex with adjustments for the rake or angle of the key arm, and spring loaded or with crush bar tighteners of gap adjustment, in this key it will be simplicity itself just a simple gap adjuster with lock nut and built in isolated resting post, with room for enhancement later. the one factor common to all good keys is a solid contact block with no movement when the contacts close, its construction is very similar to the pivot, there should be two inches left over from the construction so far, and this remaining material is cut into two 1inch lengths, Two1/4 holes are drilled in the 3/4 side, to make sure the holes line up it is a good idea to clamp the two pieces together before drilling, same care being taken as in the pivot,  then two more 5mm holes are drilled, 8mm in from the other 3/4 side
The pictures below will clarify the construction, the whole assembly is pushed together on the ceramic plates, at the same time using a steel or similar bolt a brass nut is held on the inside of what will become the top see below top right, then the whole assembly is heated up again very hot and soldered together including the brass nut, the bottom hole will be countersunk to take a small 4BA bolt with a nylon washer, with another nylon washer on the top this will be the isolated resting post, the 4BA bolt is cut so that when the key is assembled the arm will be horizontal a 2BA bolt with locking nut is now screwed into the top and will be the gap adjuster, the description of the construction of this part has been kept simplified as it is fairly obvious how it is made from the pictures, I am hoping whoever may be tempted to make this key will have grasped the rather basic concepts without to much detail, however anything that seems unclear can be discussed on the group website.