Deadfalls deal crushing damage to the victim and are very effective when used properly. But animals aren't stupid, first you have to lure them into trap and secondly you have to have a trigger so sensitive that the animal will be able to run away with your bait without collapsing it.
There are two emotions an animal is run by when finding a bait (food). The counteracting forces of fear and greed. As a trapper your task is to, as well as presenting it where the animal will find it, to reduce the fear enough to let the greed take over.
Scent is usually the mammals' primary means of identifying enemies, so leaving as little human scent as possible is important to success. The smell will wear off in time, but usually you will want success as soon as possible and then you will have to know how to reduce the scent. Some species are extremely suspecious, squirrels are generally not, so I just gently rubbed the sticks with spruce branches. If I were more serious I would hang them in smoke from spruce branches, rub them with dirt and use gloves, but hopefully this will be enough this time.
I have experimented with a lot of trigger types, but I am most pleased with the common figure 4 type. For the first time I have also set the paiute deadfall. I am pleasantly surprised with how simple it is to make with primitive tools and it's extreme sensitivity. Below is a rather poor photo of the paiute deadfall mechanism.
One was made as a traditional squirrel trap, where I know I have seen squirrels before. The logs were rotted birch, flattened with an antler axe on one side and elevated into a tree, where the squirrel feels safer.
The next one was placed directly on rocky ground under a overhanging rock. This is the experimental one. I haven't seen tracks just there, but it is right by some hazel and a big spruce so even if the trap is on the ground I hope it will be tempted to come down.
I have formerly had success with using walnuts for bait, but lacking that I used some almonds this time. So how do you get a round nut to sit onto a stick then? You drill a hole in it of course. That should also break up the inner shell of the nut and release some pleasant smells. Below: The deadfall under the overhanging rock.