Instructables
Build a very strong keychain tool from a Sawzall Blade .

Motivation:
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?'

Overview:
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:
  1. Sawzall blades are very tough metal
  2. Drilled hole with dremel grinder
  3. Shaped and cut with bench grinder

Here is a video of the final tool:


 
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Step 2: Mark hole and length

I wanted this to be about the size of a key - so I used my keys to determine the length.

I used an old screwdriver to make scratches to mark the length and hole.

Step 3: Start hole with center punch

Use a center punch to start the hole.  This will keep the bit from drifting around as you try to start the hole.

Step 4: Make a hole

It took a long time to make a hole in the blade.

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?

Test the hole. 

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 9: Put on key chain

Picture of Put on key chain
kidproquo2 years ago
I hope you don't trip with this in your pocket!

Cloudy with a chance of "Who puts a razor sharp blade within 3" of their _____"

marc.cryan (author)  twopussez10 months ago

Ha! Somebody with 4 little kids.

twopussez10 months ago

Be sure to keep that out of your pocket and well away from your nuts.

QSDR2 years ago
great idea! i read an entry last week where a chainsaw blade was cut to length and, garden hose handles glued to it to make a "pocket chainsaw" bravo (hose clamps would work well too). i saw your gutter cleaning post, i recently used a leaf blower to clean gutters, got the bulk of the leaves out by hand temporarily unclipping the gutter as i went then took to it with the blower, worked great even in the wet.
marc.cryan (author)  QSDR2 years ago
Thanks -- I had just read the 'pocket chainsaw' when I did this