NOTE SECTION 6 LAYOUT TOOLS AND PROCEDURES
- 1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Krar • Gill • Smid Technology of Machine Tools 6th Edition LAYOUT TOOLS AND PROCEDURES Section 6
- 2. 19-2 Laying Out • Process of scribing or marking center points, circles, arcs, or straight lines on metal – Indicates shape of object – Amount of metal to be removed – Position of holes to be drilled • Layouts made from baseline • Layouts of two types: basic (semiprecision) and precision
- 3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Krar • Gill • Smid Technology of Machine Tools 6th Edition Basic Layout Materials, Tools, and Accessories Unit 19
- 4. 19-4 Objectives • Prepare a work surface for layout • Use and care for various types of surface plates • Identify and use the main basic layout tools and accessories
- 5. 19-5 Layout Solutions • Layout very important to accuracy of finished product • Surface of metal coated with layout solution to make layout lines visible • Surface should be clean and free of grease • Several types of solutions available
- 6. 19-6 Types of Solutions • Layout dye or bluing – Most common – Quick-drying, good sharp background • Copper sulfate solution – Few drops of sulfuric acid added to solution gives copper-colored surface – Used on ferrous metal only – Surface must be absolutely clean of grease
- 7. 19-7 Types of Solutions • Mixture of vermilion powder and shellac – Used for Aluminum – Alcohol used to thin solution or remove it • Chalking – Mixture of lime and alcohol – Used for castings and hot-rolled steel • Readily clings to rough surface of castings
- 8. 19-8 Layout Tables and Surface Plates • Work performed on layout table or surface plate (Granite or Cast-iron) • Granite considered better (Black, Pink, Gray) – Do not become burred – Do not rust – Are not affected by temperature change – Do not have internal stresses and therefore will not warp or distort – Are nonmagnetic – Can be used for checking near grinding machines – Are cheaper than similar-size cast-iron plate
- 9. 19-9 Care of Surface Plates and Layout Tables • Keep working surface clean • Cover plate or table when it is not in use • Carefully place work on surface plate • Use parallels under workpiece whenever possible • Never hammer or punch any layout on surface plate • Remove burrs from cast-iron plates and protect surfaces with thin film of oil when not in use
- 10. 19-10 Scribers • Has hardened steel point(s) and on some one end bent at angle for hard-to-reach places • Point must always be sharp – Honed frequently on fine oilstone • Knife-edge scribers used for extremely fine lines Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 11. 19-11 Dividers and Trammels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Dividers used for scribing arcs and circles on layout and transferring measurements • Spring divider most common type – Creates circles in sizes from 3 to 12 in • Trammel – Consists of beam on which two sliding or adjustable heads with scriber points are mounted – Can do larger circles
- 12. 19-12 Hermaphrodite Calipers • One curved leg and one straight leg with scriber point • Used for laying out lines parallel to an edge and locating center round or irregular- shaped stock • For parallel lines hold scriber at 90º to edge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 13. 19-13 Squares • Used to lay out lines at right angles to machined edge, test accuracy of surfaces that must be square, and set up work for machining • Adjustable squares used for general work • Solid square: beam and blade – Used where greater accuracy required • Master squares – Used to check accuracy of other squares
- 14. 19-14 The Combination Set Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Used extensively in layout work • Consists of steel rule, square head, bevel protractor and center head
- 15. 19-15 The Combination Set • Steel rule fitted to other three parts • Square head Used to lay out angles at 45º and 90º and parallel to edge lines • Bevel protractor used to lay out and check various angles (0º to 180º) – Accuracy is ± 0.5º (30') • Center head forms center square when mounted on rule – Used for locating centers of ends of round , square, and octagonal stock
- 16. 19-16 Surface Gage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Consists of base, spindle, and scriber Used on surface plate to scribe parallel lines Some have a V-groove machined in the base, which allows them to be used on cylindrical work
- 17. 19-17 Layout or Prick Punches and Center Punches • Difference only in angle of point • Prick punch ground to angle of 30º to 60º – Used to permanently mark location of layout lines • Center punch ground to 90º – Used to mark location of centers of holes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 18. 19-18 Layout Lines • After scribed on workpiece, should be permanently marked by means of layout or prick-punch marks – Ensures layout line location visible should line be rubbed off through handling – Intersection of circle centerlines prick-punches then enlarge with center punch • Automatic center punches produces uniform spacing of marks
- 19. 19-19 Layout Accessories • Angle plate and toolmaker's clamp – Used when lines are required on face of plate – Possible to scribe intersecting 90º lines accurately • Parallels – Used to raise workpiece and maintain work surface parallel to top of surface plate • V-blocks – Used to hold round work for layout and inspection • Keyseat rules and keyset clamps – Used to draw lines parallel to axis of shaft