Layout Materials, Tools and Accessories

1. LayoutMaterials, Tools and Accessories

2. The accuracy of a layout is very important to the accuracy of a finished product. It can mean the difference between a part that is useable and one that is scrap.

3. The choice of whether to layout a part depends on the machine to be used (does it have a DRO or digital readout) and the type of operations which will be performed.

4. Sometimes it is a good idea to layout a part just to serve as insurance against machining a part incorrectly. Also you may occasionally have to machine to a layout line if it is impossible to measure a surface or if the tolerances are generous.

5. Layout solutions also known as layout dye or bluing is a dark chemical that can be applied to coat a surface. A thin layer is all that is necessary.

6. Layout dye is fast drying and provides a sharp contrast so that scribed lines can be seen clearly. Take care when applying layout as it can stain easily. The area should be well ventilated.

7. It should be removed from a finished project with emery cloth or a file to achieve maximum finish marks for your shop projects.

8. Other materials and methods that are sometimes used for coating surfaces for layout are: • Blue vitriol, a copper sulfate solution, can be used for ferrous (contains iron) machined surfaces • Chalk on rough castings • Heating the surface until it turns blue • Aluminum layout solution which is a mixture of vermillion powder and shellac

9. Surface Plates provide a good reference surface. They may be made of: • Cast iron • Granite • Ceramic materials

10. Cast Iron and semi-steel surface plates are made from good quality castings that have been allowed to age, which relieves internal stresses.

11. Granite Surface plates are available in various sizes and colours.

12. Pink marble tables contain the most quartz which means they are the most accurate or the highest grade. They are used in quality control labs and inspection room. They have the greatest wear resistance therefore do not require re-lapping as often.

13. Pink Granite

14. Black marble tables are often chosen for their ability to carry a load. Large dies can be placed on it without distortion of the reference surface.

15. Black Granite

16. Scribers are available with carbide or hardened steel points. The scriber point is tapered so that the location of the point can be easily seen when being used.

17. The point of scribers must be kept sharp so store them carefully. Refinish or “hone” with a fine oilstone when necessary.

18. Dividers and trammels are used for scribing arcs and circles. Setting the points is done using an engraved rule.

19. A trammel is used when the arc or circle is too large to be set on the divider.

20. Hermaphrodite calipers are used to scribe a line parallel to an edge or to locate the centre of a round or irregular-shaped object

21. Combination squares are useful for scribing in a variety of situations.

22. Surface gauges are used for layout and inspection. Below a scriber is mounted onto the spindle. An adjusting screw, located in the base, can be turned to allow the rocker to adjust its position or height.

23. Surface gauges can hold scribers but more often they are set up to hold dial test indicators.

24. Most of these tools would be used in what we consider to be semi-precision layout. The tolerance would usually be .020 or +/- .010.