1. DO NOW LESSON # 1)What are the 5/20/2015

2. Focus Point: What are the Types of Punches? ► Instructional Objectives: ► 1. List the purpose of various punches. ► 2. Describe the different types. ► 3. Use a specified punch. LESSON # May 20, 2015

3. I) Punches: made of hardened tool steel made of hardened tool steel The part held in the hand is usually octagonal shaped or it may be knurled, in order to prevent the punch from slipping in the hand. The part held in the hand is usually octagonal shaped or it may be knurled, in order to prevent the punch from slipping in the hand. punch is a hard metal rod (carbon steel) with a shaped tip at one end and a blunt butt end at the other that is struck by a hammer.

4. A) Center Punch ► A sharp pointed tool which is used to provide an indentation in sheet metal prior to drilling. ► If the indentation is too deep, the metal will be distorted from the blow of the hammer. However it shall be deep enough to provide a rest II) Types:

5. Various Center Punches

6. Automatic Center Punch ► Spring loaded ► No ball peen hammer required

7. B) Pin Punch ► Used to remove rivet shank from the hole of a rivet being replaced. ► Pin punches come in the exact sizes as the rivets being removed. ► Common set of punches – 3/32” 1/8”, 5/32” 3/16” & 1/4”

8. Pin Punch Cont’d. ► May also be used to align holes in the skin for faster installation. (Aligning punch) ► This differs from the pin punch in its length (6-8 inches) It tapers from 1/8” at the point to 3/8” at the shank.

9. C) Transfer Punch ► A special punch used to mark rivet holes when using an old skin as a template for laying out a new skin. ► The diameter of the punch is the same as that of a rivet hole, and the end is ground so that the mark on the new skin will be in the actual center of the hole.

10. Transfer Punch

12. D) Prick Punch ► primarily used for the purposes of layout. ► By design it produces a smaller indentation than a center punch, which acts as a useful datum point in layout operations. ► indentation made with a prick punch can be enlarged with a center punch ► A prick punch usually has a tip, that when viewed on a profile, has sides at a 30-60 degree angle to one another.

13. PRICK (PUNCH)

14. E) Hollow Gasket Punch ► Used to make gaskets for engines/carburetors - (rubber, cork, leather) ► Gasket punches come in sets for various sizes to accommodate standard bolts and studs. ► The cutting end is tapered to a sharp edge to produce a clean, uniform hole. Gasket: Stationary seal between two (2) flat surfaces.

15. Gasket Punch ► Must be placed on a wood or lead plate to prevent damage of the cutting edge. ► Now the punch is hit with a hammer, driving it through the gasket material where the holes are required.

16. F) Drift Pin (Punch) ► Commonly referred to as drift pins and starting punches. Has a long taper from tip to body. ► Made to withstand the shock of heavy blows.

17. DRIFT PIN ► May be used to free pins or bolts that are “frozen” in their holes. After the pin or bolt has been loosened the drift pin may be to large to finish the removal, then use a pin punch.

19. What must you wear when using punch?

20. SAFETY TIP: ► ► Always use the proper punch for the proper job, in order to prevent injury!

21. ► SUMMARY: (PEP TALK) ► 1. What are 3 punches used in Sheet Metal? ► 2. Compare the Prick Punch to the center Punch. ► 3. Why do we use a gasket punch. Focus Point: What are the Types of Punches?