Use any shovel long enough and you'll eventually break the handle. Replace it correctly and chances are it won't break again, at least not for a long time. The most difficult part of replacing a shovel handle is removing the rivet that holds the broken handle to the shovel blade.
By using a dremel tool, grinder, hacksaw or other tool you can remove the rivet. With the rivet removed use a nail or large pin punch to punch the rivet out of the retaining sleeve, then pull out the handle.
Replacing the Handle
Replacing the handle is a matter of purchasing a replacement handle, then sliding it into the shovel blade's retaining sleeve.
Hold the shovel by the blade, blade up, and tamp the wood against a solid surface, like the floor, a concrete slab or other hard surface to help set the handle into the sleeve as far as it will go. Tamp a couple of times until you can tell the handle has settled.
If the handle is too big to fit into the sleeve, sand or shave it down until it fits. If it is too loose, make a wedge out of a piece of hardwood, like oak, and slip it into the sleeve. Tap it down until the handle is tight in the sleeve.
Align the Grain
Replacing the shovel handle isn't difficult, but you do need to pay attention to the direction of the grain when you insert the handle. The grain of the wood should run up and down the sides of the handle, not on the top and bottom.
Pressure applied to the blade when the grain is on top of the handle will cause the handle to break sooner. Secure the blade to the handle using a rivet (preferred) or screw.
Rivet versus Screw
Once you replace your new handle you can use a screw to secure it to the blade. However, the screw will need to be tightened from time to time. If you don't, you could lose the blade, possibly at a bad time—like mid-shovel with a blade full of cement or soil.
A screw is easier and faster to use, but a rivet is a better option. It may take a little bit longer, but not much. The rivet will definitely be more permanent.
Attaching Handle with a Screw
After you've aligned the grain to the sides of the handle and set the handle, drill a 1/8-inch pilot hole about 1/4 inch in through the shovel blade's rivet hole on each side. Put a 8 x 3/8-inch stainless, self-tapping screw into the pilot holes on each side of the handle and tighten.
Attaching Handle With A Rivet
Drill a pilot hole all the way through the handle by going through the shovel blade's rivet hole with a 1/8-inch bit. Then use a bit that is the diameter of the rivet to make the hole larger. This is where your rivet will go.
Once the hole is drilled insert a rivet sleeve through the hole. Insert your rivet pin and secure it with a rivet gun or tool.