Materials and Manufacture Masonry chisels are most commonly manufactured using high carbon tool steels with a tungsten carbide tip (TCT) fused into the end. Alternatively they can be firesharp which is where they are made using high carbon tool steels only which are hardened and tempered to a sharp tip.
Standard TCT Chisels Standard masonry chisels have a high carbon steel shaft and head with a tungsten carbide (TCT) straight tip. They areavailable in a range of sizes from 1/8th inch to 2 inch and withpneumatic, ball and hammer heads. These chisels are used toproduce a variety of surface finishes and should be kept sharp at all times.
Bullnose Chisels Bullnose chisels are forged using the same materials as standard masonry chisels but are specifically designed for cutting internally curved mouldings such as cavettos and cyma- reversas. The curved tip is available in a range of sizes from 1/8th inch to 2 inch.
Fishtail ChiselsFishtail chisels are particularly suitable for carving work. They are waisted or “fishtailed” to provide clearance when carvingintricate curves and grooves. Although forged using the same materials as standard masonry chisels, these chisels are generally thinner and flatter at the tip.
Lettering ChiselsAs the name suggests, these chisels are used for fine lettering work. They have a high carbon steel shaft with TCT tip and hammer head designed for use with a dummy mallet.Lettering chisels are generally shorter in length than standard chisels and have narrow shoulders.
Granite and Marble Chisels Granite and marble chisels are generally heavier than standard masonry chisels as the materials they are used tocut are much harder than sandstone and limestone. Granite chisels are normally left with a hammer head toaccommodate the extra force required when cutting granite.
Sharpening Chisels Chisels can be sharpened either manually or mechanically. Bench grinders are the most common machine used to sharpen chisels mechanically whilst the Kaindl see-through grinding wheel is a more expensive alternative. Diamond sharpening blocks are used to sharpen tools manually but require continuous use throughout the day.
Activity 1. Name the two main materials used to produce masonry chisels. 2. What do the letters TCT represent? 3. What is a bullnose chisel commonly used for? 4. Identify two methods of sharpening chisels. 5. Why are granite and marble chisels designed to be more durable than standard masonry chisels? 6. Sketch a masonry chisel and name each of its sections.
Activity Answers 1. The two main materials are high carbon tool steel and tungsten carbide 2. TCT stands for Tungsten Carbide Tipped. 3. A bullnose chisel is generally used for cutting rounded moulds? 4. Chisels can be sharpened manually or mechanically. 5. Granite and marble chisels are more durable as granites and marbles are generally harder than sandstones and limestones.
Activity You have placed the following order with a masonry tool manufacturer. Calculate the total cost of the order including a £15.00 delivery charge.Name Quantity Cost per Unit (£) Total Cost (£)½ inch standard TCT MH chisel 5 £17.031 inch standard TCT MH chisel 10 £21.34¾ inch bullnose TCT MH chisel 7 £21.092 inch bullnose TCT HH chisel 12 £34.941 ½ inch marble TCT HH chisel 4 £32.021/8th inch lettering chisel 8 £13.60
Activity Answers You have placed the following order with a masonry tool manufacturer. Calculate the total cost of the order including a £15.00 delivery charge.Name Quantity Cost per Unit (£) Total Cost (£)½ inch standard TCT MH chisel 5 £17.03 £85.151 inch standard TCT MH chisel 10 £21.34 £213.40¾ inch bullnose TCT MH chisel 7 £21.09 £147.632 inch bullnose TCT HH chisel 12 £34.94 £419.281 ½ inch marble TCT HH chisel 4 £32.02 £128.081/8th inch lettering chisel 8 £13.60 £108.80 + £15.00 £1117.34