My dad made these stilts for me when I was maybe four or five. I have grown substantially since then, and now cannot use them without my hands cramping. So, when I found these crutches, I had an Einstein(or maybe Frankenstein...) moment. Cobble the two together, and voila! Stilts that fit! In this instructable, I will assume that you have the exact same things I have.

Step 1: Supplies

You will need to collect(be it through purchase, pillaging, knocking over people with crutches and stealing the said crutches, etc. etc.):
# stilts
# crutches
# two big bolts(or lag screws, but these will not be as secure.)
#nuts for the bolts
# hacksaw(or a coping saw)
# a whole mess of zip ties
# drill and drill bit the same diameter as your bolt.
# safety glasses. IMPORTANT! you will be cutting and drilling metal, and scraps of it will be flying everywhere!
# closed toe shoes. same reason as above.
# c-clamp or similar

Step 2: Attack of the Saw!

This should be fairly self explanatory, but here is the explanation.

You need to saw off the 'leg' of the crutch so that your stilt can go in. So take off the leg right above the screw, one pole at a time.

Step 3: Drill!

Now you will put a hole through your crutches and the stilts.
First the crutch. Mark where you would like your hole, fasten it to the table, and let fly with the drill! I hope you still have your safety glasses on, as this step is messy. It will take a bit for the drill bit to catch and bite into the metal, so just be patient and go slowly.
after the first hole, make another hole at the same place as on the first hole. after the crutch is all pierced, do the same thing to the stilt.

Step 4: Stability Is Important....

So, after I put the bolt/ lag screw in, I discovered something. the bolt acts as an axis for the crutch to spin on.
Enter...(drum roll please)
ZIP TIES!
So now we enter possibly the trickiest part of this whole operation. So, what we want to do is get two zip ties to wrap around the stilt, holding it in place. This is accomplished by taking the first zip tie and putting it through the first or second hole on your crutch, pass it around the stilt, and poke it through the hole on the other part of the crutch. Repeat with the other zip tie, except twist it around the first zip tie, and have the locky bit on the other side than the other zip tie. pull the zip ties tight.

Step 5: Learn How to Walk Again.

Ok, scratch that last bit. THIS is tricky. Re-learning to walk on these stilts is hard. To mount them, I would suggest starting with yourself and the stilts leaning against a wall, and maneuvering yourself into position. They may be a touch wobbly, but you shouldn't fall off. To dismount, lift the top part of the crutch out of your armpit, and swing it out so you don't get caught on the way down. Getting caught is rather painful and can leave quite the bruise.
And thats it! Enjoy your new, better fitting stilts!