All ice axes used to be built with a straight shaft but today this design is reserved for mountaineering and glacier travel. These are made in different length shafts from 40 to 90 centimeters. The longer axes are good for cross-country glacier travel and some easy, low-angle alpine scrambling. An ax on the shorter side is better for terrain that is a bit steeper since the distance between your grip on the ax and the slope is less in this situation. General mountaineering axes with straight shafts usually have a hooking angle of 65 to 70 degrees. This is the angle between the pick to the shaft. These axes also have less prominent teeth and fewer teeth in general on the underside of the pick. The adzes on mountaineering axes are pretty simple with a flat and straight cut and sharp edges.
There are a few straight shaft tools designed for vertical ice climbing but these are much less popular than the bent-grip or curved shaft models of vertical ice tools as the latter are easier on the wrists.
Bent Shafts (pictured above)
These axes have mostly straight shafts but the hand grip area is slightly curved. When swinging an axe like this it is a bit easier on your wrist and provides a better area for your fingers to rest though it does not protect them from being bashed. Only good technique can prevent bashed fingers. If you will be using your axe for multiple purposes, however, then know that this kind of ax does not perform as well when hammering or chopping steps of ice or when sinking the shaft into the snow.
Some axes have a bend in the shaft not at the hand grip but up just below the picks. Axes like this still work well when using the ax for mountaineering and glacier travel but will also gain slightly more clearance around bulges of ice when vertical climbing. Still other kinds of axes have shafts of which are composed of one long bend like a bow, some combine a bent-grip with a full-curve shaft. The bent-grip on these is usually quite extreme, creating a large two to three inch pocket for the hand. These ones are used for difficult vertical ice where the climber may maneuver on overhanging routes.
Picks, Hammers and Adzes
There are two kinds of ice picks. One is called technically curved and the other reverse-curved. Technically, curved picks (such as those of general mountaineering axes) are ones that curve slightly downward. Reverse-curved are slightly dished and usually used for vertical ice tools. These can be removed and replaced when worn out but are built to grip so well that while self-arresting during a high speed fall you may not be able to hold onto it when it grips into the snow. Modular ice tools are designed so that you can change a hammer and adze in and out on the back of the pick. Some hammers are round, some are square. Having the type of ice ax that has interchangeable parts is preferable.