Pencil sharpener of 6 cuts and takes practice to master without breaking the lead. Specialized sharpeners are available that operate on non-standard sizes of pencil, such as crayons used in primary schools. Sharpeners that have two openings, one for normal pencils and one for larger crayons, are fairly common. An artist's or draftsman's pencil sharpener leaves the graphite untouched and sharpens only the wood (some models can switch from standard to wood-only by an adjustment). The graphite lead is then honed to a sharp point with a lead pointer, which sharpens only the lead without wood. Lead pointers are also used with
Lead burning lines around the gums, a simple indicator for heavy metal poisoning, and by regular urine testing. Lead burning Lead burning is a welding process used to join lead sheet. It is a manual process carried out by gas welding, usually oxy-acetylene. Lead burning is carried out for roofing work in sheet lead, or for the formation of custom-made rainwater goods, gutters, downspouts and decorative hoppers. Decorative leadworking may also use lead burning, particularly where a waterproof joint is required as for planters. Lead burning is thus part of traditional plumber's work, in its original sense of a worker in lead