MEASURING AND CUTTING Chapter 4

Reading a ruler powerpoint Go over this powerpoint first: http://www.woodshopteachers.org/lessonresource s/math-resources Give students the ‘ruler’ diagram and tape in notebooks Fill in the sixteenths Write down info on last slide Students work on the 2 measurement drawing wksts as their ‘problem of the week’ Due Next Monday.

When making measurements- you must answer these questions…. How thick? How wide? How long? What are the angles? What are the diameters and depths? ***Accurate measurement and cutting are key processes in successful woodworking.

Helpful Hints: “Measure twice, cut once” Use proper cutting tools for the type of cut

Systems of Measure Customary (U.S.) SI Metric System (System International)

Customary Measurement Measures used are the inch and foot Sometimes the yard Used most in the U.S. Uses fractions of an inch Half, quarter, eighths, and sixteenths

SI Metric System Units are millimeters, centimeters, meter No fractions required Uses decimal system Measures from one system can be converted to the other Woodworking- using one or the other

Measure Tools Rules Squares Others- level, plumb, wood caliper

Rules Most measuring is done using Rules Come in 3 kinds- customary, metric or customary-metric combination

Reading a Customary Ruler Most rules are divided into major inch divisions Each inch is divided into smaller measurements (fractions of an inch) Eighths or sixteenths are the smallest

Lets examine a ruler Longest line between 0 and 1 Divides inch in 2 equal parts (1/2) Each ½ inch is divided into 2 equal parts (quarters) -1/4, 2/4 (1/2), ¾ Each quarter line is divided into 2 equal parts (eighths) - 1/8, 2/8, 3/8, 4/8, 5/8, 6/8, 7/8, 8/8 Each eighth line is divided into 2 equal parts (sixteenths) - 1/16, 2/16, 3/16, 4/16, 5/16, 6/16….etc.

Measuring Short Lengths *Bench Ruler 1, 2 or 3 ft long Folding Ruler 8” long when folded unfold to varying lengths up to 6’

Measuring Long Lengths Tape Measure Metal tape rolled up inside a case Tape is retractable Lengths 6 to 30 feet

Squares Squares- used for checking the squareness of stock, cuts, or joined pieces Pieces are square when they form a right angle (90 degrees) Combination Square

Try Square metal blade, metal or wood handle

Framing Square used in general building work Used when marking wide stock

Combination Square Has level and scratch awl Sliding head adjusts for both 45 and 90 degree angle edges Can be used as a square, marker, level, rule or gauge

Center Square Locate center of any circle Used for checking 90 degree measurements Used as a protractor

Other tools- Level Used to check a horizontal surface to see if it is level Used to check vertical surface to see if it is plumb (straight up and down) Hardwood or aluminum frames Glass tubes contain liquid with an air bubble Marks on the glass show where bubble should be located when level

Tools for Marking Sharp tool good for accurate marking Pencil- most common Easy to see, easy to remove, doesn’t scratch Utility Knife Sharp tool good for accurate marking Scratch Awl Marking & punching the location of holes to be drilled

Measure Stock The thickness, width and length of stock must be measured carefully Thickness- edge Width- shorter of the 2 sides Length- longer of the 2 sides Usually with the grain direction

SAWS

Cutting with Handsaws 4 basic types of cuts crosscut- across the grain Rip cut- with the grain Miter cut- angled cuts across the grain Bevel cut- angled cuts along the edge or end GRAIN DIRECTION

Saw Blades Described by the number of points to an inch Points- tips of the saw teeth The more points- the finer the cut Always 1 more point to the inch than there are teeth

Handsaws- Crosscut saw Kerf- thickness of saw cut - cuts against the grain - teeth are bent alternately right and left -makes kerf bigger than saw thickness - available in different length (20-26 inches is easiest to handle)

Using Crosscut Saw Use freehand to grasp the stock Hold the saw at 45 degrees Begin cutting- applying light pressure Make sure cut is square Use long, even strokes to product a smooth cut Follow the cut marks Provide support for part being cut off

Rip Saw Used to cut stock to width Chisel- like teeth Usually- 24 to 26 in long with 5 ½ points per inch Cuts are made with the grain Hold saw at 60 degrees Make several short cuts

Backsaw Very thin blade with fine teeth Used to make fine cuts- with and against the grain Name from extra piece of metal along its back Start cutting at an angle, then gradually lower until it is parallel with the workbench

Dovetail Saw Similar to a backsaw Has a narrower blade anf finer teeth Used for extremely accurate work

Coping Saw U-shaped frame Wood handle Replaceable blade with ripsaw like teeth Blade- pointed away from handle for thick stock (blade facing down) Blade- pointed towards the handle for thin stock (blade facing sideways) Take full easy strokes Guide blade to avoid breakage

Compass Saw Used for sawing curves or irregular shapes Narrow point at end- to cut small curves Cut internal openings