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.

Print both halves.
Wind thin metal coil spring into interior of smaller part.
Attach the outermost end of the metal spring to one of the notches in the smaller part by bending the metal spring.
Wrap the tape measure around the smaller plastic part holding the spring.
Fit the smaller plastic part into the larger.
Measure stuff.