Course: Biology Agricultural Science & Technology



Course: Agricultural Systems and Technology I

Unit: Fabricate with hot and cold metal.

Unit Objectives:

A. Select and use appropriate safety practices in metal fabrication.

B. Apply cold metal processes in fabrication, including measuring and marking, cutting, bending, tapping and threading, filing and drilling, and riveting.

C. Discuss the use of hot metal processes, including annealing, tempering, bending, cutting, and hole punching.

Materials Needed (Equipment):

Agricultural Mechanics Fundamentals and Application text book(Unit 21-Sharpening Tools)

3/8”x3” bolts

Tap & Die set

¾” hex rod

5/16” bar stock

3”x4½” 16ga aluminum plates

1/2 “bar stock

Drill bits

Center punch or ½ “rd bar

Cold Chisel or 1”x ¼ “ bar stock

Mower blades

Grinders-Bench grinder, hand grinder, belt sander etc.

Metal stamps or engraver

Hammer

Oxyacetylene torch

Bucket of water

Facilities:

Shop/Classroom

Interest Approach:

Prepare 5/16” solid round rod by annealing a small 3” section. While being observed by the class cut the rod into 4 20” section while keeping track of the annealed section. Invite three students (preferable the biggest/strongest 3). Give each of them one of the 20” pieces of the 5/16” round rod while keeping the annealed one for yourself. Demonstrate to the proper technique or bending and shaping the steel rod by hand. This should be near impossible for them but your bar should bend uniformly with some significant effort.

Annealing process-Heat a 3” section on a piece of solid rod with an oxyacetylene torch to glowing red for about 3 minute. Be careful not to overheat as that will create obvious texture difference on the rod that students can identify. Then gradually distance the flame from the piece to allow it to begin cooling. It should take about 5-6 minutes to remove the torch. After removing it from the torch allow the rod to cool as slow as possible. If it can be insulated to slow its cooling rate the results will be better.

Objective A:

|Curriculum (Content) |Instruction (Methodology) |

|(What to teach) |(How to teach) |

| | |

|Discuss the use of hot metal processes, including annealing, |Use the PPP and note packet to guide classroom discussion and |

|tempering, bending, cutting, and hole punching. |demonstrations. |

| | |

| |Provide handout/worksheet with terms to be defined |

| | |

| |Use the Unit 21 Self-Evaluation assessment to follow-up |

| |discussion |

| | |

Activity:

” you will proceed to the front

Objective B:

|Curriculum (Content) |Instruction (Methodology) |

|(What to teach) |(How to teach) |

| | |

|Apply cold metal processes in fabrication, including measuring |Make a Tool sharpening gauge from 16ga aluminum using the |

|and marking, |dimensions from the Student Activities section of Unit 21. |

| | |

| |Sharpen tools according to gauge |

| | |

| |Center Punch-Heat treat after sharpening according to critical |

| |temperature guidelines using a magnet. This is done by holding |

| |the center punch with a good steel magnet and heating it to red |

| |hot until it become nonmagnetic and falls off the magnet into a |

| |bucket of water. |

| | |

|Reiterate the use of hot metal processes, including annealing, |Cold Chisel-use sharpened chisel to shear 2” wide piece of 16ga |

|tempering, bending cutting and hardening steel. |sheet metal |

| | |

|Students will learn how to use metal working tools to measure, |Drill bit-sharpen Drill bit with Vertical belt sander or bench |

|bend, mark and cut aluminum. |grinder. Use 3/8” or larger. Drill hole in ¼” steel plate |

| | |

|Using the tool sharpening gauge students will learn to grind and |Mower Blade- Sharpen both ends of mower blade and balance. |

|sharpen tools to match the recommend angles of the gauge they | |

|made. |Wood Chisel-Sharpen chisel and make a hole in a 2x4” to |

| |accommodate a door strike plate. |

|Use a heat treating process to harden steel. | |

| |If needed and time permits make a steak flipping tool from ½” |

| |square stock. |

| | |

| | |

| | |

Objective C:

|Curriculum (Content) |Instruction (Methodology) |

|(What to teach) |(How to teach) |

| | |

|Apply cold metal processes in fabrication cutting, bending, |Review a Tap and Die chart and discuss the differences in bolt |

|tapping and threading, and drilling |size and thread per inch(tpi) and pitch. |

| | |

| |Select the desired size of solid round rod or bolt for the |

| |application or activity. 3/8” is a very workable size. |

| | |

| |Make extended threads on a 3/8”x3” bolt. |

| |Using ¾” hex rod cut a ½” piece and drill a 5/16” hole in the |

| |center. Use a 3/8” tap to make threads in the 3/4” bar stock. |

| | |

| | |

| | |

| |After making the nut and bolt it can be made into a Bolt Puzzle |

| |for student to keep and remember. |

Activity:

Objective D:

|Curriculum (Content) |Instruction (Methodology) |

|(What to teach) |(How to teach) |

| | |

| | |

| | |

| | |

| | |

| | |

| | |

Activity:

Evaluation:

References:

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What are the major treatments that change metal properties?

How do I use different measuring and metal shaping tools to cut, bend, drill, engrave and stamp on sheet metal/aluminum?

How are the threads on nuts and bolts made?

Questions

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