Picture of Secret Spy Shoe
Secret Boot Heel Grappling Hook

1.  8" of 1/8" steel tubing
2.  10' of 1/16m or 3/32 steel cable
3.  1/16 or 3/32 wire clamps
4.  Old pair of shoes

1.  Drill
2.  Dremmel
3.  Welder (MIG, ARC, TIG)
4.  Wire cutters

Other helpful tools
1.  Torch
2.  Vise

Step 1: Cutting

Picture of Cutting
Mark and cut the 1/8" steel tubing into two four-inch pieces.
chewie6162 years ago
i will have to make it!
santa10102 years ago
florman, you're probably safe, but please keep the following in mind:

(1) Working Load Limits are for static (nonmoving) loads, not dynamic (moving) loads.

If a cable breaks at 120 lbf (pound-force), a 95-lbf person jerking the cable at a rate of 40 ft/sec^2 would break the cable. [Calculation: 120 lbf * 32 ft/sec^2 / 95 lbf = 40 ft/sec^2]

If a 95-lbf person were to swing on a 5-ft cable that breaks at 120 lbf, he would only have to swing 3 miles/hour (about walking speed) to break it. [Calculation: sqrt((120 lbf * 5 ft) / 32 ft/sec^2) ~ 4 ft/sec ~ 3 miles/hour]

(2) Lucky for you, working loads are usually given a safety factor of 5, meaning that your cable shouldn't break until you give it a 600-lbf load. This means you (being 95 lbf) would have to jerk the cable at a rate of 202 ft/sec^2 to break it. You would also break it if you were to swing at about 6 miles/hour with 5 ft of cable.

(3) Unfortunately for frisbeechampe1983's acquiantance, the combination of swinging and abrupt stopping when he hit the wall made a large enough acceleration for the load to exceed the cable's limit.

(4) Additional notes: (a) Make sure you know the difference between mass and weight. (b) The working load limit is determined by a load being uniformly applied in a straight line pull. You are not only changing the load by moving along the cable, but any additional movement on your part makes it risky. (c) The tensile properties of the cable are changed every time you go on and off just because the loads are changing.
florman (author)  santa10102 years ago
Thanks I'l keep that in mind
johnlaw452 years ago
Where are you hiding the pillow you need to sit on after your mom caught you rapelling in your Sunday clothes?
J-Five2 years ago
You could put a phone in your other shoe!

Wait, I shouldn't give you any ideas.
g3lrod J-Five2 years ago
"This is Maxwell Smart, secret agent 86, calling for Control! Come in, Control!"
Hey mate, nice instructable, but I wouldn't recommend it on the way you use it...
The cable is very thin and you cannot hold it very well for a slow rappel... Probably another use. But GREAT idea
florman (author)  D0itYourself2 years ago
your right about the holding on part of it but the cable is rated at 120 and i'm 95.
Just remember, that 120 is also in force. I knew a kid who tried to rappel a five story gym (our high school gym had roof access.) and he thought 550 would certainly hold him. it did for the first five feet, then he tried to do a jump, when he hit the wall, the 550 snapped. luckily there was grass below him, but he broke his neck. Just remember climbing rope is safely rated at 2200 pounds of force. (22kn)
I don't mean that it gonna brake or something similar, the nature of that cable is not for rappelling
Onyx Ibex2 years ago
Very nice. Can the hook hold all your weight for a ascent or rappel? I made a concealed grappling hook a long while ago. It was a belt. the clasp was a tri-fold and assembled quickly and locked into place. The rope was already tied and acted as a belt. It worked well but was a bit tedious to unwind and rewind around the waist. I like your velcro idea a lot :)
florman (author)  Onyx Ibex2 years ago
thanks and the cable is rated to 120 so i figured since i'm only 95 i'd be okay
Machine3 years ago
Lads, that's a nice grappling hook with cable you've produced, but, it does occur to me that you have greater skills in producing interesting vids to demonstrate your new instructable. Whoever did the editing did a great job and the videoing was done well too.

Here's my suggestion;

Produce a pile more equipment accessories that are wearable and usable in emergencies and get yourselves a brand name too for those devices and vids.

You've got talent, exploit it.

florman (author)  Machine2 years ago
That's legit :)
Correct, this is most definitely an Instructable on how to construct a grappling hook show.
gunshow3 years ago
awsome place to live
florman (author)  gunshow3 years ago
drdan1523 years ago
Did you get your prize in the mail yet?!!
florman (author)  drdan1523 years ago
No not yet
They just mailed mine a few days ago ..... Hope I get it this week :-)
metroman583 years ago
when it came to the cable storage i think it might work just as well if you laced the shoes with the meatel wireing instead of to ur sock
florman (author)  metroman583 years ago
I tried that but I couldn't fit it all there.
KneXtreme3 years ago
Yay you won first prize! congrats! Yours was my favorite.
florman (author)  KneXtreme3 years ago
Great to hear thanks
suayres3 years ago
Also, don't cross your leg and rest that foot on your thigh (as so many guys do).
florman (author)  suayres3 years ago
DavidM453 years ago
Nice going kid gotta love it. FYI 1/16" Vectran rope is 800# tensile strength, coils much smaller (as in could store with hook) and 20' weighs less than an oz! The stuff is NOT available at the hardware store (www.APSltd.com) for the serious spy at $6. BTW: 1/16" 7 strand steel is 500# braking strength I don't know safe working load. Wear heavy gloves for sure!
florman (author)  DavidM453 years ago
Cool I'll add that to my instructable soon
Hate to mention it but now that you have that on instructables every kid and adult will be looking at the heels of everyones' shoes to see if they have one of those...not so secret anymore, huh? :P
olliew723 years ago
This looks like the perfect way to get tackled by a TSA official at the airport! Thanks.
florman (author)  olliew723 years ago
chenghwan3 years ago
But then, it is just a hook, the TSA officer wouldn't mind would they?
Not for genuine spies! ;-)
espdp23 years ago
Sweet idea! I LOVED the video too. Looks like it was really burning your hand by the time you reached ground? :-)
suayres3 years ago
But (sorry, it has to be said), very SMART!
HEY YOU3 years ago
Great Video!!
If you are not concerned with retrieving your hook (Q-branch would give you another in any case), you could use a carabinder on your house keys and webbing (as noted above) for a belt that would likely pass casual inspection.
Well done instructable and great acting.
ollie owl3 years ago
what happen's when walk across and leave foot print not so Secret it tell every one something is the under shoe
ramses3 years ago
Excellent! I really want one now!

Try this instead of the wire, though. It is actually used in commercial emergency rappelling rigs.

ramses ramses3 years ago
I wold also use stronger material for the hook, maybe 3/16:" + 4140 and then heat treat. W1 or O1 could be quenched in water and temper drawn in your oven.
florman (author)  ramses3 years ago
I have not had any trouble with it so far but good idea
florman (author)  ramses3 years ago
Cool but it's double the size of the cable I used.

tensegrity3 years ago
Fun idea!

Just don't try to support adult weight on 1/16" cable--working strength is only ~100 lbs. 3/32" is a bit better.
florman (author)  tensegrity3 years ago
Ye I thought about it but I decided to sacrifice working strength for size.
I just hope that the hook is buried deep enough in the heel that a tapping sound won't give up your location.

Obviously this is just a prototype. The materials will get a tweak for weight and detectability and functionality.
Puma683 years ago
First off, good job!
The last photo along with how you stored the hook, gave me an idea.
How about drilling into the side of your heel, stuff the cord in there and then fashion a plug for the hole?
Just an idea. I was coming from the "contain all that's needed in one thing" approach. Of course it would also depend on if there was room for it once you drilled for the hook. ; )
Not at all ragging on the project. You did great work.
florman (author)  Puma683 years ago
I tried to drill a hole for the cable but I only got it about 2 ft in so I started on the sock idea.

Puma68 florman3 years ago
Ah, well then your improvisation worked great!
jhangfk3 years ago
Children should not try this.
heathbar643 years ago
very cool. I like it. My experience suggests a quiker better way to make the pocket in the shoe. Just get that hook good and hot and step on it. Voila' perfectly fitted compartment. You might have to reheat it again to get the whole thing melted in flush.
florman (author)  heathbar643 years ago
Lol good idea
This is great !

How did you manage to abseil with it though ?
I think I spied bending knees, probably to appease an anxious parent.

This is a great project, though - to save the need for gloves, you could embed one of those brake things (you know, in the second Jurassic Park film, where Ian Malcolm jumps out of the high hide, and the gadget guy says he should have squeezed harder?).
florman (author)  Kiteman3 years ago
I thought about the brake thing but I needed to finish the instructable.
Kiteman florman3 years ago
I grok that - and worth missing out the brake, since you're a finalist!

(I'm right about the knees, aren't I?)
rowlands3 years ago
Great video and editing! I voted for you!
florman (author)  rowlands3 years ago
poofrabbit3 years ago
This is so cool! You have my vote, good luck!
florman (author)  poofrabbit3 years ago
Great to hear thanks.
mikeasaurus3 years ago
Great project and the action video really sells the idea. I love it!
florman (author)  mikeasaurus3 years ago
megaduty3 years ago
You had me at the action video; voted for ya!
florman (author)  megaduty3 years ago
cool thanks
KneXtreme3 years ago
Nice and simple. Great job! Voted. Does it make a clicking noise when you walk?
florman (author)  KneXtreme3 years ago
No it doesn't, I really implanted the hook in there so it wouldn't

Good question
tahirhh3 years ago
Nice, just make sure you don't wear them to the airport