Introduction: Do We Realy Have to Harden and Temper Our Blades???

About: i have spent my life finding alternative ways to get every task done in spite many challenges. most of my projects are as we call how we do things Fabrecobled (to make (fabricate) something from whatever layin…

I Started making knives the day I discovered the grinder in our farm shop. Those knives soon started to take a shape that was easy to use one handed (per my needs). In the beginning most were ground or cold forged into shape.

stock removal was ok but tedious. (lets be honest we all want to hit things with big hammers)

cold working often caused the blades to crack along the edge (but I liked how the blades could flex and not snap the tips off)

Eventually I built a small forge and learned to harden and temper my blades (this is a tedious task (particularly one blade at a time))

last year I had a thought (its dangerous I know)

"Could a annealed blade be work hardened into a suitable blade?"

Now I finally got around to this experiment.

This Instructables uses tools and heat device use the appropriate Personal Protective Equipment. YOU ARE RESPONSIBLE FOR YOUR OWN SAFETY.


Keep It Stupid Simple

I used / you may need.

  • Trashed table saw blade (the steel)
  • Something to cut out the blanks (angle grinder)
  • Charcoal grill (you want a heat source that wont remove carbon from your steel)
  • Hammer
  • Anvil or something of similar function.
  • Drills and bits
  • Center punch (as needed for pore mans Rockwell)
  • Files; coarse and fine
  • Sand paper and sharpening devices.

Step 1: Rough Cut and Aneal the Blade Blanks.

Apologies for the lack of pictures in this step I destroyed my phone and lost this steps pictures. But you can benefit from my loss by following Phone Case Improvement .

Cut your bade blanks (I used a angle grinder) or, you could (and I will) anneal the whole saw blade in the grill or just the blade blanks cut from the saw blade.

To anneal your steel.

  1. Make up the coals in your grill as normal and add your steel that needs annealed.
  2. Grill your food (no point in wasting a perfectly good fire on just steel work)
  3. Before eating make sure the steel is buried in the coals
  4. Close the vents on your grill and let it burn down over night.
  5. Now you have annealed steel (or near enough) buried in the ashes. the ashes and steel may still be hot use caution.

You can use the templet and handle I designed or design your own.

Step 2: Beat and Grind Your Blade to Shape.

  1. Use your templet to trace your blades shape onto your blade. (the block on the tang of the templet is to represent the pocket clip once its bent into shape, so add length for the clip if desired) (a neodymium magnet can hold the templet in place for tracing)(picture 1)
  2. Plan your hammer strikes, taking many passes reduces likeliness of cracking the edge. (picture 2)
  3. Hammer Time (should have beat my way from the back to the front of the blade instead) (picture 3)
  4. Regrind to shape (with experience you can preshape and then hammer the blank into the desired finished shape (its been a wile) (MORE COOLANT try not to over heat the blade; messing up our worked edges hardness.) )picture 4)
  5. Repeat until satisfied. (picture 5)

Step 3: Final Shaping

  1. Using progressively finer files or grinding equipment to smooth off the hammer strikes from the sides of the blade. This is also where if desired the bade could take a finish. (picture 1,2,3)
  2. Optional pore mans Rockwell testing. Use a center punch and hammer to divot selected spots on the blade to get a rough idea if the hardness is changing with working of the steel. aim for spots that are smooth and drop the hammer from a consistent height without adding force. (observe dimple 1 near the spine is slightly wider then dimple 2 mid blade and dimple 3 near the edge is smaller yet (picture 2,3,4) this is also a good time to center punch your hinge if you haven't already)
  3. Drill your hing hole.

Step 4: Finishing Your Pocket Knife.

  1. Determine where the tang needs to bend and be ground to form the pocket clip. (picture 1,2)
  2. Grinding is easy before bending.
  3. Bend using a vice and pliers. (picture 3)
  4. Test fit and adjust as needed.
  5. Rivet the bade and handle together with a length of copper wire. (This happened later because I thought it would be interesting to have interchangeable blades (that I haven't made yet)) see how to peen a rivet (it is a handy skill to have) (picture 5)
  6. Using fine file and wet stone sharpen your blade. (picture 3,4)

Step 5: Test Quality of Edge. (Use It and Abuse It)

I have found the best way to test if the Work Hardening experiment produced a viable blade; is simply to put it to work.

I in no way endorse smoking, is not good for your health. That said making pipes is a good skill building hobby.

  • The test wood was aged on tree mulberry and walnut (for the plug)
  • Control knife is a vintage Opinel No.07 (this knife is my EDC when I have given mine away. (highly recommend: available here )
  • The test knife removed all of the outer layers and started to shape before needing sharpened.
  • The control shaped much of the harder hart wood.
  • Finish shaping was completed with test knife.
The results.
While subjective both blades did similar work. The test knife didn't hold its edge as well as the control; but it was comparably close.
having used the test blade for a couple months now it has stood up to all my needs well.
More experimentation needs to be done; I have plans to case anneal (add carbon) the edge before work hardening to see if that improves performance. (i will update with additional case annealing step/s once that experiment is undertaken.)
It is observed that for beginner or hobbyist knife making (if reasonable steel is used) only annealing heat is needed to produce suitable knives.
I eagerly anticipate the findings of other Maker Scientists reproducing this experiment.
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