Repair of a 12 lb. sledgehammer

lathechuck's picture

I recently had to replace the broken handle of a 12 lb. sledgehammer, which I use to split wood. I'd bought the hammer at an estate sale. The head was covered in red, flaky rust, and the handle looked a little sketchy, too, but it worked for me. But, when my son swung past the wedge and caught handle on the top of the wedge, it was time to swap it out.
1. Removing the remains of the old handle. I sawed off most of the handle, so I could drill out the wood from both sides. The drilling had to avoid the steel wedge that helped keep the head from "flying off the handle".
2. Buying a new handle. Be sure not to buy only the handle, but also the little kit which should be attached to the handle, which contains a wooden wedge and a steel wedge. You'll need both, but they last guy who went home with just a handle might have come back to steal just the wedge kit, so don't buy the handle that he left behind.
3. After chewing out as much wood as possible with a drill, you can probably push the rest out with a pin punch and hammer, or just a fat steel bolt in place of the punch.
4. Now, it's time to check the hole for rust, and remove it. Rust in the handle hole, if allowed to remain, will make it harder to get a solidly-fitted handle, and might allow moisture to get into the joint, promoting both rust and rot. I scraped out the loose rust, scrubbed some out with a steel "toothbrush", and then used a Dremel sanding drum to get the rest. You'll know that you're down to clean metal when the sanding drum starts throwing sparks. This operation will produce fine rust-dust, so wear a dust mask.
5. Test fit the handle into the head. Mark one side of the handle and one side of the head, so you maintain the same alignment as you pull it out, shape it with a rasp (or coarse sandpaper), and try again. And again. And again. Until it doesn't wiggle easily on either axis.
6. Cut off most of the wood projecting through the head. With one end of the handle on the floor, drive the wooden wedge into the slot that was cut in the end of the handle when you bought it. That expands the handle on one axis. When it's in as far as it can go, cut it off flush, along with any part of the handle. Then drive the metal wedge in, perpendicular to the wooden wedge. That expands the handle along the other axis of the head. The head should be totally secure.

7. I brushed the end of the handle, and the entire head, with boiled linseed oil to protect it against further rust and rot. Time will tell whether that was a good idea or not.

This project probably took an hour or two to complete, and I know that I could have bought a brand new hammer for not much more than three times the price of the handle. This amazes me. When I think of the production processes for the forged iron head, from digging and shipping the ore, stoking the blast furnace with coke, pouring, and forging the head, it seems like a mind-boggling amount of energy invested, relative to growing, cutting, and shaping the handle. In a post-carbon world, that hammer head would be, I think, priceless.