Going (completely) Off-Topic, I just repaired a window handle. (though we are still talking of windows )
Looking at it, there were no pieces broken, there is a counterplate fixed with two M5x10 screws to an aluminum "body", simply the thread had worn off and the screws had no more grip on it.
Looking at the thread on the body I saw that it was much deeper than the length of the screws, so I thought to try using a little longer screw, thinking to use a M5x15 , and went to the hardware store and bought 20 (twenty) M5x16 screws ( they had only these, slightly longer, ones) for the price of 0.60 Euro (VAT 22% included), i.e. 0.03 Euro each ( not so cheap per unit) .
I got back and re-assembled the thingy with the new screws (that fitted perfectly) and the window handle works and is perfectly solid.
Assuming that the hardware store price for a little quantity such as 20 for these screws is 3 or 4 times the cost to the window handles manufacturer (excluded VAT) the original cost must have been around 0.007 or 0.008 each or less and the difference between a M5x10 and a M5x16 probably in the 0.001 to 0.003 Euro.
Evidently an engineer decided that in order to save 2*0.025=0.005 Euro in the manufacturing of a device that is sold for 12-15 Euro (to the window manufacturer) and which I paid actually more like 30 or 40 Euro (as part of the finished/installed window) he was allowed to introduce a defect/weak point.
This defect costed to me besides the 0.06 Euro (I still have 18 spare screws, so I will be able to fix another 9 handles when they will break in the same manner), almost an hour of time and a trip with the car to the hardware store (think of the pollution this caused).
But all in all it's fine.
What really troubles me is thinking/knowing that the next engineer will notice that the recessed screw hole is too d@mn deep for the M5x10 screw and - in order to optimize manufacturing time (saving a few hundredths of second when drilling and threading the hole) - next batch will have less deep holes, so that the handle will not be repairable in this simple way anymore.
jaclaz