Alvin - Brass Double Hole Sharpener - The Alvin Brass Double Hole Sharpener is a double-duty sharpener with a replaceable blade. The Brass Double Hole Sharpener accepts large diameter pencils up to 5/16 inches. Alvin is one of the primary sources for drafting supplies and drawing equipment in the country. Creative Coldsnow is a pround retailer of Alvin graphic arts, drafting and fine arts products.