DO NOW LESSON #

1) What are the

04/21/23

Focus PointFocus Point: : What are the What are the Types of Punches?Types of Punches?

► Instructional Instructional Objectives:Objectives:

►1. 1. List the purpose List the purpose of various punches.of various punches.

►2. 2. Describe the Describe the different types.different types.

►3. 3. Use a specified Use a specified punch.punch.

LESSON #LESSON #

April 21, 2023

I) Punches:I) Punches:

made of hardened tool steelmade of hardened tool steel

The part held in the hand is usually The part held in the hand is usually octagonal shaped or it may be knurled, octagonal shaped or it may be knurled, in order to prevent the punch from in order to prevent the punch from slipping in the hand.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.

A) Center PunchA) Center Punch►A sharp pointed tool which is used to A sharp pointed tool which is used to

provide an indentation in sheet metal provide an indentation in sheet metal prior to drilling. prior to drilling.

► If the indentation is too deep, the If the indentation is too deep, the metal will be distorted from the blow metal will be distorted from the blow of the hammer. However it shall be of the hammer. However it shall be deep enough to provide a rest deep enough to provide a rest

II) Types:II) Types:

Various Center PunchesVarious Center Punches

Automatic Center PunchAutomatic Center Punch

► Spring loadedSpring loaded

►No ball peen No ball peen hammer requiredhammer required

B) Pin PunchB) Pin Punch

►Used to remove rivet shank from the Used to remove rivet shank from the hole of a rivet being replaced. hole of a rivet being replaced.

►Pin punches come in the exact sizes as Pin punches come in the exact sizes as the rivets being removed.the rivets being removed.

►Common set of punches – 3/32” 1/8”, Common set of punches – 3/32” 1/8”, 5/32” 3/16” & 1/4”5/32” 3/16” & 1/4”

Pin Punch Cont’d.Pin Punch Cont’d.

►May also be used to May also be used to align holes in the align holes in the skin for faster skin for faster installation. installation. (Aligning punch) (Aligning punch)

► This differs from the This differs from the pin punch in its pin punch in its length (6-8 inches) length (6-8 inches) It tapers from 1/8” It tapers from 1/8” at the point to 3/8” at the point to 3/8” at the shank. at the shank.

C) Transfer PunchC) Transfer Punch

►A special punch used to mark rivet A special punch used to mark rivet holes when using an old skin as a holes when using an old skin as a template for laying out a new skin.template for laying out a new skin.

►The diameter of the punch is the same The diameter of the punch is the same as that of a rivet hole, and the end is as that of a rivet hole, and the end is ground so that the mark on the new ground so that the mark on the new skin will be in the actual center of the skin will be in the actual center of the hole.hole.

Transfer PunchTransfer Punch

D) Prick PunchD) Prick Punch

► primarily used for the primarily used for the purposes of layout. purposes of layout.

► By design it produces By design it produces a smaller indentation a smaller indentation than a center punch, than a center punch, which acts as a which acts as a useful datum point in useful datum point in layout operations. layout operations.

► indentation made with a prick indentation made with a prick punch can be enlarged with a punch can be enlarged with a center punch center punch

► A prick punch usually has a tip, A prick punch usually has a tip, that when viewed on a profile, has that when viewed on a profile, has sides at a 30-60 degree angle to sides at a 30-60 degree angle to one another.one another.

PRICK (PUNCH)PRICK (PUNCH)

E) Hollow Gasket PunchE) Hollow Gasket Punch

►Used to make gaskets for Used to make gaskets for engines/carburetors - (rubber, cork, engines/carburetors - (rubber, cork, leather)leather)

►Gasket punches come in sets for Gasket punches come in sets for various sizes to accommodate various sizes to accommodate standard bolts and studs. standard bolts and studs.

►The cutting end is tapered to a sharp The cutting end is tapered to a sharp edge to produce a clean, uniform hole.edge to produce a clean, uniform hole.

Gasket: Stationary seal between two (2) flat surfaces.

Gasket PunchGasket Punch

►Must be placed on a Must be placed on a wood or lead plate wood or lead plate to prevent damage to prevent damage of the cutting edge. of the cutting edge.

►Now the punch is hit Now the punch is hit with a hammer, with a hammer, driving it through driving it through the gasket material the gasket material where the holes are where the holes are required.required.

F) Drift Pin (Punch)F) Drift Pin (Punch)

►Commonly referred to as drift pins and Commonly referred to as drift pins and starting punches. Has a long taper starting punches. Has a long taper from tip to body. from tip to body.

►Made to withstand the shock of heavy Made to withstand the shock of heavy blows. blows.

DRIFT PINDRIFT PIN

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

What must you wear when using What must you wear when using punch?punch?

SAFETY TIP:

►Always use the proper punch for the proper job, in order to prevent injury!

► SUMMARY: SUMMARY: (PEP TALK)(PEP TALK)► 1. 1. What are 3 punches What are 3 punches

used in Sheet Metal? used in Sheet Metal?

► 2. 2. Compare the Prick Compare the Prick Punch to the center Punch to the center Punch.Punch.

► 3. 3. Why do we use a Why do we use a gasket punch.gasket punch.

Focus PointFocus Point: : What are the What are the Types of Punches?Types of Punches?