Wednesday, April 23, 2014

Katy Bar the Door

<======Back to Part II, Door #2

Don't you hate it when you carefully document every step of a project with photos and then find out the memory card was not seated when you try to down load them?

As noted in the previous post, even steel, exterior doors are structurally vulnerable to delaminating at the lock/dead bolt when impacted.  That is due to the whitewood and particle board core.  One way to address this deficiency is to provide a redundant load path to pick up the load when the door fails.  That is, bar the door.

Parked.  No door trim installed.
1/8" galvanized steel cable, 2000 lb breaking strength.  Bushing is Zareba  ICDB-Z.  Two wraps of cable around bushing.  Three gritted crimping sleeves Zareba HTGCS2425.  The bolt is 3/8 inch by 4 1/2 long lag bolt.  Bolt could be longer due to  length being consumed by drywall and length of bushing.

3/8"  by 3 1/2 inch eye-bolt.  Eye was heated and opened up as shown.  Painted flat black.  Installed at 58" above floor.  58" is elevation of Deltoid muscle on 50% male.

The cable simply slides in.

Same Eye-bolt as above but the "rams horn" curls the other way.  This bolt is installed at 36 inches which is the elevation of the Greater Trochanter of a 50% male.  As before, the elevation is taken from the floor that the bad guys will be standing on.

It pops into place.  Note that most battering ram tools will challenge the door at this elevation.

System relaxed.  It stays in place because of gravity and the springiness of the cable.  For those with inquiring minds, no, this is not my bedroom.
System under stress. Two strands of cable, each with a breaking strength of 2000 pounds.  That is a lot of comfort.  I recommend replacing the cable if it is ever seriously challenged.
The studs that the hardware were screwed into are 34" from center-to-center.  The cable was cut to 124" in length.  The bushings were positioned so the centers were 15" from the ends.  The cable assembly ended up being 94" from bushing-center-to-bushing-center.  I will probably make it two inches shorter center-to-center next time.  I will also make a simple fixture with spindles at the desired center-to-center distance to simplify fabrication.

A couple of nice things about this system is that the cable is a fair devil to cut, even if the bad guys had the foresight to bring the proper tools.  Another nice thing is that the cable is unobtrusive so it is hard for the bad guys to figure out what they are can even be aligned with the framework of any window panes in the door.  Finally, it is a little bit more stylish than a two-by-four and big steel brackets.  That matters when there are womenfolk ERJ must make happy.  This cable was painted flat black but it could be painted any color.

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