Introduction: Razor Sharp Razor Blade Knife

When you need a knife that is razor blade sharp why not use a razor blade?  Usually it's because razor blades on their own are so damn dangerous.
This project turns a razor blade into a very handy, compact, accurate and most importantly, safe knife.

Warning:  this project involves very sharp implements!  If you are the sort of person who cuts themselves easily on kid's safety scissors then you should probably think twice before making or using this.

Step 1: Tools and Materials

  • a razor blade (obviously).  I got a pack from ebay.
  • a lid of an empty ice cream container or other similar soft plastic container.
  • a craft knife (or one of these razor blade knifes if this isn't your first one)
  • a drill or dremel
  • a heat gun or hair dryer
  • a ruler or straight edge
  • two small screws and nuts

Step 2: Making It

Carefully cut the plastic lid to get a rectangle of the appropriate size for the blade.  It has to be large enough to fold around the blade.
Now fold it in half.  It won't want to stay like this.  The plastic is quite springy.  Use a heat gun or hair dryer to heat up the plastic so that you can get a nice permanent fold.  I used my metal ruler to press down on the hot plastic.  
Be careful not to burn yourself or heat the plastic so much it melts or catches fire.
The edges of the plastic rectangle might not line up perfectly.  Just trim them if that's the case.
Now lay the blade on the plastic.  Mark in two places where to drill holes for the screws.  These will hold the blade in place.
Drill the holes right through both layers of plastic.
Lift one side of the plastic and insert the screws through the other layer.  You can then drop the blade in place.  Push the layers together again so the that screws push right through.  Tighten the nuts onto the screws.

There should be only a small part of the blade exposed.  Just a millimetre or two.  You don't want too much because the blade will flex and be hard to control.

That's it!

Step 3: Using the Knife

As you can see from the pictures, because of the way it is held, it makes for very accurate cuts for projects such as paper craft. 

It could also be a useful item in a survival kit. 

If it starts to get dull, turn it around and use the other end of the blade.  When that gets dull, undo the screws, flip it over, tighten them up again and use the opposite blade!

New blades cost very little but if you really want to get your money's worth out of them you could try keeping them sharp like this.

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