Update! I found that although the part printed fine, I only used a 15% fill and it flexes too much when using it on my Dremel. Re-ran a file with 100% fill - stay tuned. I also bumped the scale to 101% to fit the closed end better on my Dremel....
Customized version of http://www.thingiverse.com/thing:69655
Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=69655