stress line and keyboard screw for the T60

[ZDiablo]

This morning I upgraded the memory in my T60 and decided to blow the dust out of the fan assembly while I was at it. When I was reassembling my computer I noticed a line (stress line??) going across the bottom side which lines up with screw hole for the keyboard. I do not know if this is normal or if it is a stress line. I can see it when the lighting hits it just right and I can feel it. The screw used for the keyboard is the same as the 4 screws used for the palm rest. Also the screw for the keyboard is not flush with the surface and I’m afraid I will strip out the plastic if I try tightening it even further. Is the line across the bottom of the laptop normal and was the correct screw being used for the keyboard?

[truk]

I don't have a machine, but if it's a stress line it's likely to have undefined end points (fades out where there's no creases or bends in the plastic) and a shrinking thickness along it's length. If it's built in the plastic, it will have defined endpoints, regular thickness and height, and run straight and parallel with the sides of the case ( or possibly the piece it's on,) as a rule.

[meekus]

Injection molded plastic parts will tend to feature "mold lines" where the various parts of the mold itself butt up against each other and "knit lines" where the disparate globs of molten plastic flow together as one inside the mold. Neither lines are automatic stress lines.