Introduction: Secret Spy Shoe

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.

Step 2: Bending

Picture of Bending

I found that the easiest way to bend the tubing was to put the metal in a vise and heat it up as hot as I could.  Then, I was able to bend it into a hook shape.  Do that with both pieces.  

Using my MIG welder, I welded the two hooks together.

Step 3: Cutting

Picture of Cutting

Taking the hook and one of the old shoes, I traced out the hook pattern on to the heel of the shoe.  After doing that, I put the shoe in my vice and drilled a 1/4" hole 3/4 of the way through the sole of the shoe.  This is the point where you begin to dremmel.  I dremmeled out a pattern in the shape of the hook into the heel of the shoe.  I then drilled a hole through the heel and into the inside of the shoe.  It is through this that the cable will go.  Once I had the hook well-embedded into the heel of the shoe, I had to glue a small magnet into the heel to secure it.

Step 4:

Picture of

To store the cable, I decided to use an old sock and a piece of velcro.  I sewed a band of velcro on to the sock so that it formed a little velcro latch that holds the cable.


Cat00x (author)2015-12-08

Cute video. That must have been fun to make. But he forgot his gun when going overboard!

hflorman (author)Cat00x2016-06-29


chewie616 (author)2013-06-28

i will have to make it!

santa1010 (author)2012-10-28

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)santa10102013-02-15

Thanks I'l keep that in mind

johnlaw45 (author)2012-10-28

Where are you hiding the pillow you need to sit on after your mom caught you rapelling in your Sunday clothes?

stephenham5511 (author)2012-10-28


J-Five (author)2012-10-28

You could put a phone in your other shoe!

Wait, I shouldn't give you any ideas.

g3lrod (author)J-Five2012-10-28

"This is Maxwell Smart, secret agent 86, calling for Control! Come in, Control!"

D0itYourself (author)2012-10-28

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)D0itYourself2012-10-28

your right about the holding on part of it but the cable is rated at 120 and i'm 95.

frisbeechamp1983 (author)florman2012-10-28

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)

D0itYourself (author)florman2012-10-28

I don't mean that it gonna brake or something similar, the nature of that cable is not for rappelling

Onyx Ibex (author)2012-10-28

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 Ibex2012-10-28

thanks and the cable is rated to 120 so i figured since i'm only 95 i'd be okay

Machine (author)2012-08-11

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)Machine2012-10-28


Thundermoon99 (author)2012-08-11

That's legit :)

mrmerino (author)Thundermoon992012-09-13

Correct, this is most definitely an Instructable on how to construct a grappling hook show.

gunshow (author)2012-08-01

awsome place to live

florman (author)gunshow2012-08-06


drdan152 (author)2012-07-03

Did you get your prize in the mail yet?!!

florman (author)drdan1522012-07-09

No not yet

drdan152 (author)florman2012-07-11

They just mailed mine a few days ago ..... Hope I get it this week :-)

metroman58 (author)2012-07-10

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)metroman582012-07-10

I tried that but I couldn't fit it all there.

KneXtreme (author)2012-06-26

Yay you won first prize! congrats! Yours was my favorite.

florman (author)KneXtreme2012-06-26

Great to hear thanks

florman (author)2012-06-23

Paracord would probably work fine but you might want to check the working load on it.

suayres (author)2012-06-18

Also, don't cross your leg and rest that foot on your thigh (as so many guys do).

florman (author)suayres2012-06-19


DavidM45 (author)2012-06-19

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 ( 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)DavidM452012-06-19

Cool I'll add that to my instructable soon

Shadow Ranger (author)2012-06-19

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

olliew72 (author)2012-06-14

This looks like the perfect way to get tackled by a TSA official at the airport! Thanks.

florman (author)olliew722012-06-18


chenghwan (author)2012-06-17

But then, it is just a hook, the TSA officer wouldn't mind would they?

espdp2 (author)chenghwan2012-06-18

Not for genuine spies! ;-)

espdp2 (author)2012-06-18

Sweet idea! I LOVED the video too. Looks like it was really burning your hand by the time you reached ground? :-)

suayres (author)2012-06-18

But (sorry, it has to be said), very SMART!

HEY YOU (author)2012-06-18

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 owl (author)2012-06-17

what happen's when walk across and leave foot print not so Secret it tell every one something is the under shoe

ramses (author)2012-06-17

Excellent! I really want one now!

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

ramses (author)ramses2012-06-17

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)ramses2012-06-17

I have not had any trouble with it so far but good idea

florman (author)ramses2012-06-17

Cool but it's double the size of the cable I used.


tensegrity (author)2012-06-17

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)tensegrity2012-06-17

Ye I thought about it but I decided to sacrifice working strength for size.

burntapplepie (author)2012-06-17

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.

Mr Rancher (author)2012-06-17

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.

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