WARNING:
This is not a structural print. If you put enough force on the blade, IT WILL GO THRU THE PLASTIC. The two piece design will do it even worse. If you are going to try to cut something tat needs a lot of force to get thru, use a real utility blade holder. If you are going to use this for small and easy to cut items, go ahead.
I warned you, but it is common sense, metal is stronger than plastic.

Scale: 1:1 in Inches

Update: If you are having problems with the one piece design
Get:
07 slim blade rev 3 Front - Print 1
07 slim blade rev 3 Back - Print 1
07 slim blade rev 3 Pin - Print 2

I want a Rexford Knives RUT (Rexford Utility Tool) but I am unwilling to spend $150 on one.
I looked at it and boiled it down to the features I want.
Which are:
1) Hold and lock a Utility blade in a safe way
2) Small
3) A hole for a length of paracord
4) Easy to use
I went through 3 revisions:
Rev 1
Too thin, hard to get the blade out
Rev 2
Good thickness but the blade is hard to get out and the lock doesn't always work well
Rev 3
Good thickness, blade stays in, bigger window for easier access to the blade