The handles of heavy-hitting sledgehammers receive a lot of abuse while in use. When the sledgehammer handle fails, you can replace the broken handle and save the head of the hammer. The process of installing a replacement handle to your sledgehammer depends on the type of material used to make the handle. Traditional wood handles use friction to hold the handle in place. Fibreglass handles rely on an adhesive to keep the head of a sledgehammer from flying from the handle during use.
Clamp the head of the sledgehammer in the jaws of a vice with the damaged handle facing up.
Set the blade of a hand saw against the bottom of the sledgehammer head with the blade resting against the damaged handle. Saw the handle off even with the side of the hammerhead.
Align the thin end of a replacement handle with the section of damaged handle sitting inside the head. Hit the thick end of the handle with a hammer to drive the remaining portion of old handle through the head.
Heat the sledgehammer head with a propane torch to roughly 176 degrees C if the remaining section of damaged handle is set in epoxy. Remove the remaining section of handle as described after the head cools to room temperature.
Set the thin end of a wooden replacement handle in the opening of the hammerhead. Thin the end of the handle with a wood rasp if it does not fit in the opening. Remove only enough wood to allow the handle to fit tightly in the head.
Remove the head from the vice.
Set the thick end of the handle on the ground. Slide the head on the thin end of the handle. Push down on the head to seat it on the handle.
Lift the assembled pieces off the ground a few inches and tap the assembly forcibly on the ground to drive the head tightly onto the handle.
Slide the wood wedge supplied with the handle into the slot located on top of the handle extending beyond the hammerhead. Hit the wedge with a hammer to drive it into the handle.
Cut the thin end of the handle even with the sledgehammer with a handsaw.
Set the metal wedge supplied with the handle perpendicular to the wooden wedge. Drive the wedge into the handle with a hammer until it sits even with the top of the sledgehammer.
Mix two-part epoxy in equal parts on a piece of cardboard.
Roll the thin end of a fibreglass handle in the mixed epoxy. Slide the coated end of the handle into the opening with the hammerhead facing up in the bench vice.
Push and hold the handle in the opening of the sledgehammer head.
Remove the sledgehammer from the vice when the epoxy cures and holds the handle tightly in place.