Difference between revisions of "Tools/forge/induction"

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(Start editing down to just induction stuff)
(cut out excess from workshops)
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What we're going to do
Describe the basic forging, shaping, drawing out, bending
 
Making a small utility knife
 
I've made 3 blades so far, all successful but am not an expert
 
Show the metal, micarta, rivets, wood. Show the knife
 
Describe the basic forging, making tang, drawing out blade, grind, harden, grind, handle, sharpen
 


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


What steels we have available
    
 
   1095 – Standard, easy to work with, sharp, OK toughness, rusts
 
                EN47 - +£5, TOUGH! OK sharpness, rusts, harder to work
 
  Others I can get if you want to go further but don't have right now
 


Welding onto the dop rods
Welding onto the dop rods


Anyone competent does their own, anyone else I do
  Emphasise use a LOT of weld material
 
Emphasise use a LOT of weld material


  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


Squaring it off but not all the way to the dop rod
  Just getting the feel of beating on the metal, try both hammers, see what it's like
 
The need to keep it roughly oblong
 
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
  Don't touch metal to anvil till you're ready to strike


  Correct any error immediately, don't let them grow
  Correct any error immediately, don't let them grow
Forming the Tang


  Consider the shape we're working towards
  Consider the shape we're working towards
Think of width you want, 15-20mm? And thickness, 3-4mm
Need to get the thickness about right but go a touch over on the width


  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


  We can't fix over-thinning
  We can't fix over-thinning
Don't need to get the end neat, we're going to be grinding it off


  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


  Keep thinning, flattening, drawing out till there's room for a good grip
  Keep thinning, flattening, drawing out till target shape


  Try to get the surface nice, so we can do less grinding
  Try to get the surface nice, so we can do less grinding
Establishing the notch on the edge of the anvil and beating out the burr, don’t make it too big
Reducing the tang width a bit if you can
Keeping the spine flat


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


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
Drawing out the blade
Bringing the blade to a similar size to the tang but longer
Keeping the bar uniform, don't try to narrow the cutting edge yet
Using the notch to define the boundary where to stop working
Cutting of excess if needed
As always, correcting any problems as soon as they appear
Trying to get the surface smooth, 5 minutes hammering can save an hour's grinding
Try to avoid twisting, use the grips and fix to fix it if it happens
Forming the point
Beating behind the point to start the drop but only just behind
Avoiding "fish-lips"
Forming a symmetric point using the edge of the anvil
Letting the length increase to maintain the thickness
Being careful as things get thinner, reducing hammer force
If an edge gets folded over, have to cut it off, can't fix
Thin the point a little but don't make it delicate
Dropping the point
Explain how the metal will try to move once we forge the edge
Dropping the point to prevent banana-shaped knives
Using the horn of the anvil to make the drop not the edge
Beating the blade back flat if needed and keeping forming the drop
FIX ERRORS AT ONCE!


Normalize and Anneal
Normalize and Anneal

Revision as of 14:17, 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.