Mechanical pencils are handy to use with their ever-sharp tips. They make constant sharpening of dull and broken pencil points unnecessary. With a click or a twist, sharp new lead is dispensed and ready for use. The only requirement is the occasional need to add fresh lead.
Grab the correct size refill. Not all pencil lead refills are the same diameter. Look on the mechanical pencil for the lead size. Printed on it, often near the eraser, you'll find the correct pencil lead refill size (0.5 mm or 0.7 mm).
Look for a "click button." It can be the entire top of the pencil or a small button on the side. (If there is no click button on the pencil, proceed to Step 3.) Press and hold the button while tapping the mechanical pencil in an upright position. (This allows any lead particles to fall out.) Gently insert the new pencil lead refill into the shaft, and then release the button. Click it repeatedly until your newly replaced lead is in the correct position.
Search for a "twist" mechanism. You can twist some mechanical pencils by twisting a small section clockwise. You may find the twistable area at the top of the pencil, or the section nearest the point. (If there isn't a twist mechanism, proceed to Step 4.) Carefully twist the section clockwise to open the shaft fully. Insert the pencil lead, refill the preferred depth and then twist counter-clockwise to tighten.
Remove the eraser. In some mechanical pencil models, an open shaft for lead insertion lies hidden beneath the eraser. To replace the pencil lead, simply drop one piece into the tube. In such models, you can remove the eraser quickly and simply. If the eraser doesn't pop off easily, discontinue the effort and proceed to Step 5.
Pull and twist the mechanical pencil gently to see if it disconnects into 2 pieces. Some models pull apart to reveal the lead refill shaft. Drop the lead into the tube and reconnect the mechanical pencil for use.
Dispose of disposable models if you cannot replace the pencil lead. Disposable models are non-refillable. Simply throw the mechanical pencil away.
If the pencil lead slides out, either the mechanism is still engaged or it's the wrong size refill.
Never force lead into a mechanical pencil. If it becomes jammed, it can be difficult or impossible to remove. If the lead won't go in, it's either the wrong size, the mechanism is not engaged, the pencil is non-refillable or a piece of lead is already jammed in the shaft.