If you are a do-it-yourselfer and need to get working on any piece of equipment before you use it, then making a set of dumbbells at home is the way to go. Dumbbells are often needlessly expensive and shoddily made, so making a set at home is a cheap and easy alternative. Follow these steps to make your own dumbbells.
Start with a 1-inch cold rolled steel bar that is in good condition. You can decide on the length of the bar, but something like 10 inches is a good approximation. Leaving about 6 inches in the middle (enough for your hand to grip the bar), place two clamp-on collars near the center of the bar. On the outside of the collars put two 1-inch washers.
Put the shims on. For the next step, you need to put a total of 4 shims on the bar. The shims should be 1-inch inside diameter, 1.5-inch outside diameter steel shims. Place a shim near the end of the bar and another just outside of the 1-inch washer. Then do the same on the other side of the bar. To finish this step, wrap a few rounds of durable tape on the either side of each shim so that the shims stay in place on the bar.
Add the weight pipe. Take two 1.5inch ASA 80 pipes (1.9-inch outside diameter, 1.5-inch inside diameter) and place one on each end of the bar. You should basically be inserting the base bar into these hollow pipes. The pipes should fit snugly over the bar and should swivel around the shim with some resistance, but not too much.
Collar and clamp the ends. The final step is to secure the ends of the dumbbell with a screw shaft and a collar. On the end of each side of the bar, set a 1 15/16-inch screw shaft. To secure the closing, use another set of steel one piece clamp-on collars, with 1-inch inside diameter. Make sure the collars are set tightly. Test the dumbbell with increasing weight to make sure that the parts are secure and that the two pipes are able to revolve on the shims.