I had a spring loaded retractable measuring tape which stopped working. After trying to get it to work I figured I might as well take it apart. After all, a spring loaded retractable measuring tape that doesn't retract is just a bulky measuring tape. It turned out several small plastic components inside had broken and were now either so destroyed I couldn't measure/replicate them or were just plain missing.

Version 1: Uploaded 2010-02-02
http://makerblock.com/2010/02/retractable-tape-measure-reloaded/

Version 0: Uploaded 2010-01-30
http://makerblock.com/2010/01/new-print-retractable-measuring-tape/

For a larger picture and a little more detail, visit my blog at http://www.makerblock.com

First I designed a small flat open ended cylinder which would hold the metal spring. It had to have two notches - one notch to hold the end of the tape measure and another to hold the outer-most end of the metal spring.

Then I designed a plastic holder for the small flat cylinder to fit into. It has a small spindle/axle in the center with a notch for the interior end of the metal spring.

FAIR WARNING: The interior spindle snapped right off when I tried to assemble this. Thus, I had to improvise a little to put it together. If you look closely, you\'ll notice both the spindle and the interior edge of the larger part have a slight overhang to help keep the other parts in. I built these features in hoping that it would just hold itself together. In the end I just put two bolts through it to make it more permanent. That\'s why the picture you see has two M3x16 bolts/M3 nuts holding the interior part in place. It doesn\'t spin quite as freely as I\'d like - but it does work.

This was really just a way for me to fritter away some time and over-engineer something that wouldn\'t have even cost me $2 to replace entirely. If I were to design this from scratch I would build it to use a skate bearing inside, captive nut, and short bolt.

I've included the Sketchup files in case someone wants to take this further.