Making a 1/6 Scale Prosthetic Hook

Claudia wearing a hook

When I ran out of spare Cy Girl hands, I decided to fit Claudia with a prosthetic split-hook instead.
My intention was to make the hook functional, so it could be used to grip and hold objects. This way having a hook would provide an advantage over other Girls with normal looking hands with fixed poses as those can only hold objects of certain sizes.
I made a pair of hooks: one left-handed, one right-handed, this page describes how I made the hooks.

Later I test-fitted Vera with the left-handed hook.

Tools and materials needed:

how to make a hook

Here is a picture with a drawing, the pair of hooks I made and a CG v1 hand for comparison:
The righthand hook (top) is viewed from the top, the lefthand hook (center) is viewed from the (in)side.
I made the righthand one first, then checked the result with some Googled pics and noticed that the radius of the outside part of the hook is often larger than that of the inside part, so I made the lefthand hook that way.
For reference, the grid on the green cutting mat in the picture is 10mm based.

The outside part of the hook is fixed, the inside can be rotated open by pulling the 'thumb' backwards towards the elbow. There is a small slot cut on the inside of the tip of the thumb to fit a small wire to operate the hook. However you need a figure with posable shoulders to be able to operate the wire, a BBI Perfect Body or a Ladies Mission body has this, the CG v1 body that Claudia is based on has fixed shoulders so I left the cable off.

The drawing shows a righthand hook part by part:

Two more parts are needed:

Making a hook

Here is how to construct the hook:
Start by finding a small screw of suitable size (old mechanical alarm clocks are a useful source).
Take the length of wire and pull a tight full circle loop in the wire, for a righthand hook the loop needs to be to the left and the part that will become the 'finger' should cross underneath the stem.
Adjust the loop so that the screw fits tightly but still moves freely without binding.

Cut the wire to size, the stem should be about 18mm, leave the 'finger' part a little longer for now to make it easier to handle while bending.

Now pull a tight 3/4 circle loop in the remaining wire, for a righthand hook this loop should go to the right with the part that will become the 'finger' crossing over the part that will become the thumb.
Adjust this loop so that it will fit the screw tightly without slipping.
Fold the tip of the 'thumb' upwards using a pair of flat nosed pliers.
If you plan to fit a wire to the thumb, use a thin X-Acto saw blade suitable for metal to cut a small groove on the inside of the thumb.

Vera wearing a hook

Determine the size of the radius of the hook, the ones I made are a bit small, especially considering that CG hands are slightly oversized.
The exact curves, shapes and sizes of prosthetic hooks tend to vary a lot as far as I can tell, so you can't go wrong.

Slip the scrap vinyl tube over the finger, use round nosed pliers to bend the finger, once the shape looks right, slip off the vinyl tube again, repeat for the other finger.

Assemble the hook by inserting the screw through the loop of the fixed part of the hook, then screw it into the loop in the movable part.
If the screw sticks out from the bottom of the assembly cut it off or sand it down.
If the movable part fits too loose around the screw you can use a drop of Epoxy Glue or Liquid Thread Lock to fixate the screw.

Finally I used a metal file to create a flat surface on the insides of the tips of the fingers (indicated by the shaded part on the drawing).

Slip the rubber band over the fingers all the way to the hinge.

Slip the 20mm length of vinyl tubing over the stem and slip the washer over the tubing.
I rounded off the rear edge of the vinyl tubing just enough to get it to slip into the locking groove inside a CG arm, this will keep the hook from dropping out of the arm.
With some arms the locking groove is slightly wider, for those cases I made a small cut in the edge of vinyl tube and work some cotton thread into the cut.

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