Scaling to driscrete values - not factors


is it possible to scale instead of factors to a specific value?

While doing precision modeling I find it harder and harder to get exact geometry with only factorial scaling.

Is there a way to just mark an edge and scale it to 5 units and not times 5?
Ideally the even while a whole mesh is selected, only the active edge gets scaled. That way you even scale spheres just by their radius.

Yes, I think that this is possible. A problem arises that say, take your basic cube, get into edit mode (edge select) and ummm just rotate the cube so that you can see all of the edges. Go ahead and select an edge. Now hit the Nkey. You should see a whole new drop-down. Under transform you will find info about your edge. Also, turn your widget thingy on, this will help to explain (I hope).
Okay, just for fun now, please note that your transform widget thing is at the median point of the edge, that is to say, in the middle. Alright, let us scale this edge along a particular axis. We do know how to do this right?
Then as you watch the N panel, You will see values changing under the transform panel. Oh yes you will! Now, the interesting part is that you can enter directly any of the values you see changing. Just use the Shift key while in that field.

Hope this helps a bit.

Yes I know about that one, but it only is useful when you start with a cube with lies exactly on the xyz and its terribly unprecise. If I scale one axis down to 1.99m the edge length in edit mode is still shown as 2m.