Eraser Do I Need?
Unfortunately, as with most writing things, erasers were
standardized over the years, nor are they now! However, there
are a few common sizes that fit a good many of the pencils made.
The easiest way to determine what size eraser you need
mechanical pencil is to measure the diameter of your old eraser in
millimeters. If the eraser is gone, take a measurement of the opening
where the eraser goes. Rulers work fine for this, but if you have a
caliper, it will work even better!
If all else fails, and no erasers are the correct diameter for your pencil (yes, it happens!), you may have to consider creative alternatives. Carving your own eraser refills is an option. Good old fashioned Pink Pearl erasers work well for this, as do Magic Rub white vinyl erasers. If you're handy, you can also make a metal "punch" and punch out refills from a larger block style eraser. A piece of paper makes a good shim, if a ready made eraser almost fits, sometimes all it takes is a small piece of paper wrapped around the base of the eraser to make it fit just right. On the opposite end of this theory, sometimes taking a ready made eraser that is just a tad bit too big and shaving off a little bit will provide you with the correct fit. You just need to think outside the box a little bit when it comes to refilling erasers on your vintage mechanical pencils.
List of Mechanical Pencils and Eraser Sizes