You cut the edges off an old blade. Put under the main blade increasing the distance between the safety bar and the main blade making the razor more aggressive. You can add more shims this way making your 3 piece razor adjustable.
Wow! Put two shims in my DE89 and what a difference! I kinda felt like I been needing a more agressive shave and this did the trick.
Dropped a pair of pruned-off blades under a fresh Feather in my very mild-shaving late-40's gold Tech last night; wow! Whole new razor! Thanks for the tip, guys!
I think I'll try the same tomorrow; "if some is good, more is better" theory may work, but it may bite, too--I'll post the results..