It is often a desperate move scratch at something with your keys. At best you will tear up whatever you are trying to cut or pry, at worst you will break your key and be stranded. I've tried to make a keychain tool that could replace a small pocket knife or utility knife -- so I would think 'where are my keys?' instead of 'where are the scissors?'
The first half shows how to make a simple saw keychain. In the second half I do some more detailed grinding to make a knife-like tool that fits well in my finger tips.
Some key points:
- Sawzall blades are very tough metal
- Drilled hole with dremel grinder
- Shaped and cut with bench grinder
Here is a video of the final tool:
Step 2: Mark hole and length
I used an old screwdriver to make scratches to mark the length and hole.
Step 3: Start hole with center punch
Step 4: Make a hole
I tried a regular drill bit with poor results.
A blue grinder from a dremel kit worked well, the bit was nearly destroyed.
I made a jig by putting nails into a board very close the blade.
Step 5: Is the hole big enough?
The hole here is a little too small to fit over both rings of the keychain. Measuring the keychain, the hole needs to be almost 0.2"
Step 6: Grind to a shape
Removing several teeth makes the saw easier to hold.
Step 7: Polish on grinder
Step 10: Test it out
Step 11: Make another with the other end of the blade
Step 12: Grind shape and polish
I tried to give the back of the blade a curve. Also ground off several teeth to make a little handle.
Step 16: Make better
It is now pretty kick-ass.
I will(might) post details when(if) I get a chance.
Step 17: Testing some more
Step 18: Problems
Step 20: Start of the grinding wheel
Step 21: Detailed work with dremel tools
Step 22: Sharpen
Step 23: Sharpen the curved side
I sharpened these by going back and forth between the curved side and the flat side. You sort of get a little sharp edge that bends back and forth, when it is gone the blade should be very sharp. I test the sharpness by dragging the blade gently across my fingernail -- it should immediately catch the nail. In some of the pictures you can see little chunks of my finger nails missing from this. A dull blade will just slide across the surface.
Step 24: Polish
There are dremel tools that are grit and rubber -- but I didn't have any on hand.