D.L.
I don't want to start a debate over the correct term/name.
You can call them what you like.
However, it was my understanding from my research that a compass or a "pair of compasses" were when a pencil or pen is attached for drawing on paper or other materials.
When the pencil is removed and the leg is refitted with another spike, the tool is then called a "dividing compass" or a "set of dividers" or a shorten name "dividers"
.
I site as my research this page I found:

http://encyclopedia.thefreedictionary.com/Dividers

And this text:
Dividers

A dividers, also known as a measuring compass, is a mathematical, drafting or cartographic instrument used to aid measurements of the length of irregular lines and of distances on maps or charts. It is commonly used in geometry and in nautical navigation. It is similar in appearance to a drafting compass, the difference being that the compass has a spike on one end and a pencil (or other drawing utensil) on the other which allows the drawing of circles, whereas the dividers has spikes on both ends. Often a compass can be fitted with a spike in place of the drawing utensil and thus converted to dividers.

Which I found by researching the name compass.
And this text from the same dictionary:

Compass (drafting)
In some medieval illustrations, the compass was used as a symbol of God's act of creation

A compass or pair of compasses is a technical drawing instrument that can be used for inscribing circles or arcs. As dividers, they can also be used as a tool to measure distances, in particular on maps. Compasses can be used for mathematics, drafting, navigation, and other purposes.

Compasses are usually made of metal, and consist of two parts connected by a hinge which can be adjusted. Typically one part has a spike at its end, and the other part a pencil, or sometimes a pen. Circles can be made by fastening one leg of the compasses into the paper with the spike, putting the pencil on the paper, and moving the pencil around while keeping the hinge on the same angle. The radius of the circle can be adjusted by changing the angle of the hinge.

Distances can be measured on a map using compasses with two spikes, also called a dividing compass. The hinge is set in such a way that the distance between the spikes on the map represents a certain distance in reality, and by measuring how many times the compasses fit between two points on the map the distance between those points can be calculated.

All of the pictures you have shown, do not show a pencil; most likely as it hadn't been invented, yet, and it may true that the name was changed at the time of the Renaissance, in reality what you are trying to construct, in my opinion, would be a "dividing compass".