Tools/forge/induction: Difference between revisions
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What we're going to do |
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Making a small utility knife |
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I've made 3 blades so far, all successful but am not an expert |
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Show the metal, micarta, rivets, wood. Show the knife |
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General Safety |
General Safety |
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Effects of oxidizing and reducing flames – Scale, Temperature, Decarburization |
Effects of oxidizing and reducing flames – Scale, Temperature, Decarburization |
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What steels we have available |
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1095 – Standard, easy to work with, sharp, OK toughness, rusts |
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EN47 - +£5, TOUGH! OK sharpness, rusts, harder to work |
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Others I can get if you want to go further but don't have right now |
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Welding onto the dop rods |
Welding onto the dop rods |
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Anyone competent does their own, anyone else I do |
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Need to normalize the welds |
Need to normalize the welds |
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Heating to a suitable colour, testing with magnet if you need to |
Heating to a suitable colour, testing with magnet if you need to |
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Squaring it off but not all the way to the dop rod |
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The need to keep it roughly oblong |
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Don't touch metal to anvil till you're ready to strike |
Don't touch metal to anvil till you're ready to strike |
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Correct any error immediately, don't let them grow |
Correct any error immediately, don't let them grow |
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Forming the Tang |
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Consider the shape we're working towards |
Consider the shape we're working towards |
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Think of width you want, 15-20mm? And thickness, 3-4mm |
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Need to get the thickness about right but go a touch over on the width |
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The need to come to both dimensions at once and not over-work in one direction |
The need to come to both dimensions at once and not over-work in one direction |
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We can't fix over-thinning |
We can't fix over-thinning |
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Don't need to get the end neat, we're going to be grinding it off |
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REMEMBER TO CORRECT ERRORS AT ONCE |
REMEMBER TO CORRECT ERRORS AT ONCE |
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Cycling draw out and flatten |
Cycling draw out and flatten |
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Keep thinning, flattening, drawing out till |
Keep thinning, flattening, drawing out till target shape |
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Try to get the surface nice, so we can do less grinding |
Try to get the surface nice, so we can do less grinding |
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Establishing the notch on the edge of the anvil and beating out the burr, don’t make it too big |
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Reducing the tang width a bit if you can |
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Keeping the spine flat |
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Normalizing |
Normalizing |
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Furnace cooling as an option for normalization but not annealing |
Furnace cooling as an option for normalization but not annealing |
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Shut down the forge |
Shut down the forge |
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Marking out the area of "hot things" when leaving |
Marking out the area of "hot things" when leaving |
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Drawing out the blade |
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Bringing the blade to a similar size to the tang but longer |
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Keeping the bar uniform, don't try to narrow the cutting edge yet |
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Using the notch to define the boundary where to stop working |
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Cutting of excess if needed |
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As always, correcting any problems as soon as they appear |
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Trying to get the surface smooth, 5 minutes hammering can save an hour's grinding |
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Try to avoid twisting, use the grips and fix to fix it if it happens |
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Forming the point |
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Beating behind the point to start the drop but only just behind |
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Avoiding "fish-lips" |
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Forming a symmetric point using the edge of the anvil |
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Letting the length increase to maintain the thickness |
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Being careful as things get thinner, reducing hammer force |
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If an edge gets folded over, have to cut it off, can't fix |
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Thin the point a little but don't make it delicate |
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Dropping the point |
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Explain how the metal will try to move once we forge the edge |
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Dropping the point to prevent banana-shaped knives |
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Using the horn of the anvil to make the drop not the edge |
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Beating the blade back flat if needed and keeping forming the drop |
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FIX ERRORS AT ONCE! |
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Normalize and Anneal |
Normalize and Anneal |
Revision as of 13:17, 10 September 2018
Describe the basic forging, shaping, drawing out, bending
General Safety
Clothing, overalls best, nothing flammable, avoid synthetics
Heavy boots, toe-capped preferred
Goggles AT ALL TIMES WHILE FORGE IS LIT
Welding gloves
Ear protection while hammering
Good air circulation, monoxide hazard and detectors
Clearing the area around the forge of all flammables
Everyone knows how to use fire extinguishers?
In case of fire, TURN GAS OFF!
What types of extinguisher to use on what sort of fire
We cannot extinguish metal fires, use the vermiculite to smother
NEVER use an extinguisher on the forge it's self, it has nothing flammable anyway
Hazards of the oil for quenching
Hazards of metals high in nickel, chrome, cadmium etc, and protection needed
Arc-eye hazards of welding
How steels behave and heat treatments
Use the diagram to explain things
The states the steel can be in, what is critical temperature and why it matters.
Form above critical
Plannish under critical
Using a magnet to test for critical, but learn to use colour
How different types have different hot-hardnesses
Stainless needs a lot more heat
Damascus needs even more
Cover annealing, hardening, normalizing
Effects of under-heating and over-heating – Stress cracks, decarburization, crumbling
Effects of oxidizing and reducing flames – Scale, Temperature, Decarburization
Welding onto the dop rods
Emphasise use a LOT of weld material
Need to normalize the welds
They are GOING to break, what to do when they do
Watch for starting of cracks
DO NOT TRY TO CATCH THE HOT METAL
Pick it up IMMEDIATELY with grips, place onto hot-safe surface
Lighting the forge
Describe the forge and it's parts
How the tunnel can be opened longer for bigger objects
Never use brick choke and rear door at the same time
Check it over for damage
Vacuum out tunnel – clean before use, not after
Plug it in!
Checking the gas & air valve positions are closed
Start the blower
Let a little air into the forge
Cover the dramatic differences in gas and air settings
Turning on gas at the bottle and burners
Opening the main gas valve and using the lighter to get it lit
Adjusting the gas and air valves to get a flame the right size and slightly reducing
Demonstrate high/low, oxidizing/reducing, show what they look like
Large flames are more stable, small flames may result in burner over-heat, check this often
Demonstrate high/low flames
Starting up the second burner if you have a need to for a long object
Normalizing
Why we need to normalize
What it does
Proper procedure
What happens if we're not hot enough, or too hot!
Flattening out the rod
Heating to a suitable colour, testing with magnet if you need to
Just getting the feel of beating on the metal, try both hammers, see what it's like
Don't touch metal to anvil till you're ready to strike
Correct any error immediately, don't let them grow
Consider the shape we're working towards
The need to come to both dimensions at once and not over-work in one direction
We can't fix over-thinning
REMEMBER TO CORRECT ERRORS AT ONCE
Looking at the metal as it cools, seeing what needs to change
Drawing out using small hammers, large hammer on step, large hammer on side, edge of large hammer
Cycling draw out and flatten
Keep thinning, flattening, drawing out till target shape
Try to get the surface nice, so we can do less grinding
Normalizing
Repeat the normalization cycle
Furnace cooling as an option for normalization but not annealing
Shut down the forge
Air off – Gas off – Air on
Leaving the air running to cool the forge if needed
The forge may stay hot enough to start fires for up to 2 hours
Marking out the area of "hot things" when leaving
Normalize and Anneal
This is the last chance to smooth out any gross surface defects or geometry errors
Using a little less heat than before as we're not trying to cause bulk movements
Planishing using the smaller hammers to smooth things as best we can
Normalize for at least 2 cycles and maybe more
Fix geometry before cycles
Using the vermiculite to slow down cooling to achieve maximum softening or furnace cool
Shutting down the forge
As before for shut-down
Letting the forge cool down enough before putting it away
Hand-in-tunnel test
Don’t try to clean inside the tunnel, put it away dirty
Watching out for condensation dripping off the gas bottle
Getting the blades out of the vermiculite and cleaning up.