Basic Techiques of Blacksmithing: A Manual for Trainers (Peace Corps, 1982, 102 p.) Day 2 Session: 5. Properties of metals Session: 6. Forging a blacksmith's cold chisel Session: 7. Forging: a blacksmith's hot punch Session: 8. Heat treating

Basic Techiques of Blacksmithing: A Manual for Trainers (Peace Corps, 1982, 102 p.)

Day 2

Session: 5. Properties of metals

Total Time: 1 hour

Objectives:

* To determine the type/grade of available junk steel
* To discuss the properties and characteristics of various grades of steel
* To identify potential uses of available steel

Resources:

* Attachment 5-A, "Identifying and Testing Scrap Metal"
* Andrews, "Carbon Content of Steel for Different Uses," page 127
* Weygers, "Steel for Blacksmith," page 15

Materials:

A variety of junk steel salvaged from wrecked autos and rail cars; e.g., leaf springs, coil springs,
axles, torsion bars, linkage rods, push rods, valves, rail tie, plate, rail spikes, rail section, side or
bed plate from rail car, sill from rail car, etc.

Procedures:

Step 1. (10 minutes)
Explain the objectives and distribute Attachment 5-A, "Identifying and Testing Scrap Metal." Ask the group to read it.

Step 2. (15 minutes)
Select a piece of junk steel and demonstrate how to identify its type and properties.

Trainer Notes * Note and discuss the significance of color, weight, surface finish, sound when dropped, and flexibility. * Have the participants discuss the junk items' previous use and postulate the type of steel of which it is made. * Describe and perform the spark and quench tests to further verify the type of steel. * Based on the reading, the tests, and the previous use of the item, ask the group to discuss its composition (% of carbon) and qualities (hardness and elasticity). * Explain how heating, forging, and heat treating affect the characteristics of different steels. * Discuss the advantages and disadvantages of the three types of steel.

Step 3. (15 minutes)
Have participants divide into four groups and select, identify, and describe the properties of an item of junk steel.

Trainer Notes * Explain that the groups should follow the same identification procedure as done by the trainer until they are fairly certain of the type of steel. * Stress that not all of the testing methods necessarily have to be used. * Assist groups who may be having difficulty.

Step 4. (10 minutes)
Reconvene the groups and have them report on their junk item.

Trainer Notes If a group's conclusion is inaccurate, discuss their identification process in order to pinpoint where they went wrong.

Step 5. (10 minutes)
Have participants examine the chart on Page 4 of the Attachment and identify potential uses of the scrap items listed.

Trainer Notes * Ask the group to focus on those items most available in their areas. * Explain that the chart can serve as a resource in the future for identifying possible sources of material.

Attachment 5-A

IDENTIFYING AND TESTING SCRAP METAL

Identification

A variety of unknown types of steel are encountered when working with scrap metal. Several simple tests exist which the blacksmith may use to identify these unknowns. Because of logistics, it may not be possible to perform all of the tests, but with one or two of these tests and some experience, one can learn to recognize useful metal at a glance.

There are several types of "steel" that (for the most part) we will not be dealing with in the context of these classes. They are: cast steel, cast iron, high alley steels, and stainless steel.

The other common metals found in scrap that we will not deal with are copper and aluminum; we will use brass for brazing.

The types of steel that we are looking for may be divided, for the sake of simplicity, into three categories: low carbon, medium carbon, and high carbon steel. The percentage of carbon present determines the major properties (i.e., hardness, fusibility, toughness). Only the medium and high carbon steel; are temperable.

Low Carbon: contains about .05-.30% carbon and of the three, because of the relative low cost of production, it is used extensively. Some sources of low carbon scrap are car bodies, some types of rebar, old nails, bolts, panels on railroad cars, railroad spikes, some types of angle iron, rolled pipe, some types of wire, nails, straps, hinges, tanks, drums, etc. It is manufactured in rolled bars, and the most common ones are round, flat or square bars of ¼ - 1". It is NOT temperable but may be forge welded.

Medium Carbon: contains roughly .30-.60% carbon. It is a harder material (harder to work and harder to find), and may be tempered. It is the most available temperable scrap metal. Some sources are springs, axles, torsion bars, gearshift bars, shock absorber bars, and, in general, anything that must stand up to a higher degree of stress and strain. It will not bend easily like mild steel. It is also used where tempering is required (e.g., auto/truck axles, auto/rail car springs, leaf springs, steering columns).

High Carbon: contains roughly .60-1.5% carbon, and usually has an alloy present. It is much harder than medium carbon, but is available in scrap sometimes as old pneumatic drill bits, old bulldozer blades, milling cutters, metal saws, cutting dies, threading dies, and files.

Testing

Spark Test: Hold a piece of the material in question against a high-speed grinder and closely observe the sparks given off. Generally, the brighter and more explosive the spark, the greater the carbon content of the steel in question. Try known pieces and study their relationships.

Sound Test: If the piece is small enough, lightly toss it onto a concrete floor or stone. Listen for the sound, and compare the sound to known pieces.

Cold Chisel Test: Using a sharp cold chisel and light blows, attempt to cut the beginning of a curl from the material in question, noticing the following points:

- Does the material cut easily or does it resist?
- If it resists, does it nick the chisel blade?

Again, compare a known material with the piece in question.

File Test: This test is fairly self-explanatory. Using a file, test the surface for hardness. This also reveals the color of unoxidized metal.

Hardening Test: Take the piece in question and heat its tip to light cherry or dark orange and quench it in water. Test it with a file, and note:

- Does the file slide over it like glass?
- Do the teeth bite slightly, or is there no difference between the hardened part and the rest of the piece?

Again, if in question, test against a known piece.

Previous Use: One of the most important clues in determining the type of steel in question (whether tempered or not) is to be found in its previous use. If a piece of steel would have needed to be exceptionally tough, tempered, and/or abrasive-resistant to perform Its function (e.g., torsion bar, spring, pneumatic bit), then we can assume with greater certainty that it is some type of medium to high carbon steel.

TEMPER TEST

If an untested spring is to be used for tool making, it is advisable and practical to perform the temper test.

Temper test

Flatten evenly a 4" section.

Perform the water quench (heat reserve method) on the end, quenching before the colors run the entire length of the piece.

Strike with hammer.

Critical color is determined by where the break occurs in relation to the patina. Tools from this spring should then be tempered at the color/temperature prior to the critical color.

SCRAP METAL IDENTIFICATION - A. Atkeison

TEST METAL	COLOR	SOUND	BENDING	MAGNETISM	SPARK	FILE	COLD CHISEL	PREVIOUS USE (EXAMPLES)
ALUMINUM	silver, oxidizes white	high-pitched ringing	varies	non-magnetic	none	easily & clogs teeth	easily	non-ferrous (cans, roofing)
STAINLESS STEEL	silver, does not oxidize		tough	both magnetic. & non-mag. types		smoothly
COPPER	soft reddish orange		bends easily
CAST IRON		no ring; thin pieces break when dropped	brittle, will not bend	magnetic	dull red lines	easily	chips	evidence of mold
CAST STEEL						files, but is tougher than cast iron		evidence of mold
LOW CARBON STEEL			easily		bright reddish, non-explosive	files
MED. CARBON STEEL			very difficult to impossible		bright, semi-explosive	files
HIGH CARBON STEEL			does not bend		very bright, explosive	difficult
BRASS

Session: 6. Forging a blacksmith's cold chisel

Total Time: 3 hours

Objectives:

* To identify and discuss different types of chisels and steels suitable for making chisels
* To practice uncoiling an automobile spring
* To hot-cut steel
* To make a cold chisel blank
* To use a grinding wheel and practice grinding techniques

Resources:

MacPherson, "The Cold Chisel"
Weygers, pages 45 and 59

Materials: Automobile coil spring, 112" to 5/8" diameter (1¼ cm) (each team should have one coil spring available at their station), several types of chisels, woodworking, metalworking, stoneworking, etc.

Trainer Notes * The chisels distributed in Step 2 should be assembled in advance. * The procedure for making the cold chisel should be prepared on newsprint and ready to post in Step 9.

Procedures:

Step 1. (5 minutes)
Explain the objectives and outline the procedures.

Step 2. (10 minutes)
Identify and pass out several different types of chisels. Ask participants to try to determine the uses, properties, and forging methods of each one.

Trainer Notes * Have the group compare the shape and design of the chisels. * If possible, invite the group to experiment cutting with the chisels. * Discuss the significance of the angle of bevel in cutting edges. * Ask participants to speculate on the type of steel and temper of the various chisels. * Also ask participants to give examples of how they have used one or more of the chisels in their work. * Describe some potential dangers in chisel use, e.g., chipping the blade, striking hand with hammer.

Step 3. (5 minutes)
Ask the group to refer to the list of scrap metals from the last session and identify which ones would be most suitable for chisel-making.

Step 4. (5 minutes)
Display a cold chisel and ask the participants to explain its properties and uses.

Trainer Notes * Refer the group to Session 4 when they used a cold chisel to cut round bar. * Have them discuss other potential uses. * Based on the chisel's function, ask the group to determine its carbon content and temper.

Step 5. (5 minutes)
Light your forge.

Trainer Notes * If coal is used as a fuel, demonstrate how to build a fire using coke remaining from the first fire. * If possible, ask one member of the group to review the steps involved in lighting the forge and have another assist you.

Step 6. (10 minutes)
Heat and uncoil two linear feet of bar from an automobile spring.

Trainer Notes Emphasize to the group: * the correct positioning of the coil spring in the fire * the periodic turning of the spring to prevent burning * the banking of the fire around the spring * the importance of even heating * the proper use and type of tongs for holding the spring

Step 7. (5 minutes)
Explain to participants how to determine the length of bar necessary to forge a chisel, to determine the point, and to hot-cut the bar accordingly.

Trainer Notes Be sure to point out: * that the spring should be cut most of the way through, then broken, to avoid damaging the hammer on the hardy * that the hardy should be removed from the anvil when finished * safety hazards involved in the process (i.e., hot foot)

Step 8. (25 minutes)
Have participants go to their assigned stations and ask each team to light the forge, heat and uncoil the available spring, and hot-cut the straightened bar to be used for the chisel.

Trainer Notes * To make sure all participants understand the task, ask for a volunteer to repeat the steps. Also, ask if there are any questions before beginning. * During the work, circulate among the stations providing input when necessary and encouraging appropriate hammering and accurate blows. * Be sure to point out any hazardous practices.

Step 9. (5 minutes)
Reassemble the participants around your station, and explain the steps involved in making a chisel.

Trainer Notes * Point out what you expect to accomplish during each heat and mention that they can expect to accomplish less for each heat. * Have the steps outlined and posted on newsprint. * The following steps may be included on the list: - forge stock into eight-sided octagonal bar - forge main bevel - grind cutting edge - chamfer striking end

Step 10. (10 minutes)
Demonstrate the forging of the cold chisel.

Trainer Notes * Refer to each step as you work. * Before you grind the demonstration chisel, point out injuries which can occur from improper grinding practices (i.e., the importance of wearing safety glasses).

Step 11. (5 minutes)
After the demonstration, review the steps with the group.

Trainer Notes * Ask if there are any more questions before the group makes their chisels.

Step 12. (1 hour, 15 minutes)
Have participants return to their stations and forge, grind and chamfer the cold chisels.

Trainer Notes * Again, circulate among the stations, giving input regarding hammering techniques, safety, etc. * Have teams who finish early assist others in the final steps of grinding and chamfering.

Step 13. (10 minutes)
Reconvene the large group and ask the participants to identify and discuss problems encountered while making their chisels.

Step 14. (5 minutes)
Conclude the session by explaining to the group that they will temper their chisels during Session 8, "Heat Treating."

Trainer Notes Briefly mention that the chisels are incomplete until annealed and tempered; two processes which will be discussed in depth during Session 8.

Session: 7. Forging: a blacksmith's hot punch

Total Time: 2 hours

Objectives:

* To identify and discuss different types of punches and their functions
* To make a blacksmith's hot punch

Resources:

* Andrews, page 52.

Materials: 10 - 15 automobile coil springs (6" length and 3/4" to 5/8" in diameter), and a variety of punching tools.

Trainer Notes The punching tools distributed in Step 2 should be assembled in advance. They should include at least two types of hand-held blacksmith's hot punch, several cold punches, drifts, mandrels, an awl, nail sets, and center punches.

Procedures:

Step 1. (5 minutes)
Explain the session objectives and briefly outline the procedures.

Step 2. (10 minutes)
Distribute among the participants a variety of punching tools used by crafts people and discuss their uses and properties.

Trainer Notes * Stimulate a discussion of each tool by asking: - What are some potential uses for this punch? - What can be determined regarding the qualities of the steel from which this tool is made? - What are some scrap steels from which this tool could be made? - Which of these punches are used by local crafts people at your work sites?

Step 3. (10 minutes)
Focus the discussion on the hand-held blacksmith's hot punch and ask participants to identify how it is used.

Trainer Notes Some important uses of the punches which should be mentioned include: * piercing sheet metal (cold) * center punching to mark stock * driving out old rivets, shafts, etc * hot punching * drifting (enlarging) holes

Step 4. (10 minutes)
Briefly explain the procedures involved in making a blacksmith's hot punch.

Trainer Notes * Be brief in your explanation and be sure to mention the importance of making the hot punch long enough to allow holding it while maintaining a safe distance from the heat of the piece being punched. * Point out and explain the parallels which exist between the procedures for making a hot punch and those involved in making a cold chisel. * Explain that the punch blanks will be annealed and tempered in the next session, along with their cold chisels.

Step 5. (15 minutes)
Demonstrate the techniques involved in making a hot punch.

Trainer Notes * Before beginning the demonstration, remind participants that they should observe carefully and note any procedures which appear confusing and may need to be clarified later. * During the demonstration, focus your explanation on identifying transitions from one major step to the next.

Step 6. (10 minutes)
Have the participants review and explain the procedures and techniques which they observed.

Trainer Notes * Before proceeding to the next step in this session, be certain that all the participants have had the opportunity to clarify the procedures such that they are ready to begin working at their stations.

Step 7. (50 minutes)
Have participants form their work teams and practice making a hot punch.

Trainer Notes * Circulate among the groups making suggestions, providing assistance, and pointing out safety precautions and examples of good hammering posture.

Step 8. (10 minutes)
Reconvene the group and ask participants to discuss and share among themselves any technical difficulties which they encountered and what they did to overcome them.

Session: 8. Heat treating

Total Time: 2 hours

Objectives.

* To define and discuss the terms hardening, annealing, and tempering.
* To anneal steel.
* To temper steel.
* To evaluate the problem-solving techniques used by the work teams.

Resources:

* Attachment 8-A, "Water and Oil Quenching"
* Andrews, pages 49-53
* Weyger, pages 36-37
* Weyger, back cover

Materials: Chisels and punches made during Sessions 6 and 7; a piece of coil spring for demonstration of tempering.

Procedures:

Step 1. (5 minutes)
Explain the session objectives and briefly outline the procedures.

Step 2. (15 minutes)
Distribute Attachment 8-A, "Water and Oil Quenching" and ask participants to define and discuss the terms annealing, hardening and tempering.

Trainer Notes * Stimulate discussion by having participants describe common techniques used by local blacksmiths to harden steel. * In defining the terms be certain that the following key points are discussed: - the method of water-quenching in hardening and tempering - the method of oil-quenching in hardening and tempering - the concept of correct hardening temperature - degrees of hardness - the importance of annealing before hardening to relieve built-up stresses * If available, distribute among the participants examples of tools which have been tempered and annealed and have them explain why it is important to harden certain tools.

Step 3. (20 minutes)
Using a punch and chisel blanks made during the previous sessions, demonstrate the proper techniques involved in annealing and tempering.

Trainer Notes * Before beginning the demonstration, briefly describe the procedures to be followed and remind participants to observe carefully. During the demonstration, mention and point out the following: - that annealing is a slow process which can take 20-30 minutes in some cases - that the tempering area should not be windy since this causes scaling - that the fire should be clean and free of clinkers and other debris - that oxidation can be minimized by maintaining a low, steady air blast - that care must be taken not to burn cutting edges while heating the stock - signs and causes of steel stress and over-heating * Following the demonstration, take a few minutes to ask participants to review and clarify the important techniques which they observed.

Step 4. (45 minutes)
Have the participants go to their work stations and anneal and temper the punches and chisels which they made in Sessions 6 and 7.

Trainer Notes Circulate among the teams and provide assistance and guidance whenever necessary. However, it can be assumed that, at this point, the participants have become more comfortable with the forge environment. It is important to begin to limit interventions by the trainer to situations involving potential safety hazards and/or situations in which participants are involved in fruitless pursuits which will prevent successful completion of the task. In this manner, by encouraging as much independent experimentation as possible, the participants are given the opportunity to creatively solve their own problems.

Step 5. (15 minutes)
Reconvene the group and ask participants to discuss and share among themselves any difficulties which they encountered and what they did to overcome them.

Trainer Notes Explain that they will be annealing and tempering other tools during the week to strengthen their skills.

Step 6. (20 minutes)
Have the participants discuss the problem-solving techniques used in their work teams up to this point.

Trainer Notes * Briefly explain that in order to transfer the skills which they acquire during this training, participants will, most likely, be communicating and working cooperatively with a local blacksmith. * Stimulate discussion and dialogue among the participants by asking the following questions: - What are some examples of situations in which it was difficult for your team to work effectively? - What was done to help solve these problems and move on? - What factors served to inhibit effective problem-solving? - What can be done in the future to improve your team's ability to work more effectively and cooperatively? - To what extent does the work team design of this training reflect the situation of working with a local blacksmith at your sites?

Attachment 8-A

WATER AND OIL QUENCHING

Water quenching

WATER QUENCHING (Heat Reserve Method) - After bringing 3" of the blade end of the piece up to heat:

- quench only the tip (1½") leaving the next 2" or so unquenched.

- move the piece up and down ½" in water rapidly to prevent forming a fracture zone where heat contacts water. Maintain this until the heat glow has diminished to a dull cherry.

- Remove the piece from quench and briskly polish the blade surface with an abrasive. Hold the piece with blade upward and observe the color patina as the heat from reserve moves toward the edge. When the desired color reaches the edge, then quench quickly with a swirling motion.

Oil quenching

OIL QUENCHING - After bringing 2" of the blade end up to heat:

- with a swirling motion, plunge completely in oil quench bucket, holding the lid nearby in case of an oil flash. If the oil flashes, pull tongs out of the way and snuff fire with tight-fitting lid.

- After the piece has been quenched in oil and is cool to the touch, polish and draw color patina over a propane flame or in a forge, using a metal plate with a hole cut in it (or fire bricks) to direct heat to the piece.