Mystery of the missing screw

You just received that much anticipated ThinkPad T series and you are eagerly unpacking it.   Upon removing it from the plastic bag, you are busy installing the battery and familiarizing yourself with the various ports.   You turn it over and note the various screw holes on the bottom, all filled with screws as they should be.  Many have little icons next to them of a memory chip, or a keyboard, which indicate which screws would need to be removed to get inside the unit to add memory in the future.   You also note the two keyboard drain holes that have no screws in them, and a small icon of a keyboard and droplet of liquid next to each.  All as it should be. Then, you notice a countersunk hole, somewhat larger in diameter than the others, near the right side of the machine.  (toward the left side when viewed upside down with the system turned over)   No screw.  Curious, you peer into the hole and note the threaded brass insert that would clearly accept a screw.   Is one missing?  How could Lenovo have carelessly let slide this minor detail?

This screw is a security screw that once installed, prevents the ultrabay device from being ejected from the system.  (see location circled in red in photo above)  As most users wish easy access to swap ultrabay devices as they use their systems in everyday environments, the factory default is to not install the screw.  Lenovo includes 2 of these security screws in a small plastic bag included in the box with your new system.   Only one screw is required, but a spare has thoughtfully been provided.   The P/N for the bag and two screws is 42W3824 on current T series ThinkPads.

Here is another view for more clarity.    The screws require a small Allen (hex) tool for installation.  While not entirely tamper proof, a casual passer-by won't be able to remove your drive using a coin or car key as a makeshift screw driver.    As this feature has been part of ultrabay equipped ThinkPads for several generations, this feature may be old news to many of our customers, but upon hearing recent customer inquires made to sales  on this subject, I thought it might be an opportunity for a bit of show and tell.  

UPDATE

Shortly after I posted this, I found out that systems being built in June, 09 onward, we were eliminating this small bag of 2 screws from the ship group . We found that  few users actually used these screws.   This eliminated waste and reduced cost allowing us to be more competitive.  The amount saved was actually fairly significant, believe it or not.   For our more technical customers who would like to take advantage of this feature, I would recommend either ordering the assortment of service screws (FRU 42X4676 for T61 era systems or FRU 45N3853 for newer T400/T500/W500 systems).  These assortments are handy to have as they include spares of all the different screw types used in the system)