Metal Collapsible Niddy-Noddy

Ever walked into a yarn store and gazed longingly at those coiled hanks of brightly-colored yarn, perplexed as to how they got into such bundles? Enter the niddy-noddy! These tools (shaped like a capital 'I' but with the short arms perpendicular to one another) are used by hand-spinners and home yarn-dying operations to:
-Obtain approximate yardage of the yarn
-Prepare handspun yarn for finishing and dying
-Create a large loop of yarn that can then be twisted into a hank for easy storage or display

A little bit industrial-primitive, a little bit steampunk, a whole lotta awesome: this niddy-noddy was designed to stand out in the crowd of wooden and PVC niddys.  All parts were sourced from your average big box hardware and craft stores, with the exception of the leather scraps and gate hooks (which were left over from a long-since-forgotten project).  Total cost was roughly $30 (but that includes enough material to may two niddy-noddy bodies and three pairs of arms).

This Instructable assumes that you have general mechanic competence and know the basics of niddy-noddy design and use.

MATERIALS:
(Qty x Item)
1 x Aluminum tube (square), 1" x 1" x 3'
1 x Aluminum (flat), 1/8" x 1-1/4" x 3'
1 bag (6 pcs/bag) x Machine screws, #6-32 x 1-1/2"
1 bag (6 pcs/bag) x Cap nut, #6-32
1 bag (30 pcs/bag) x Washer, #6
1 bag (5 pcs/bag) x Cotter pin, 1/8" x 3/4"
2 bags (2 pcs/bag) x Nylon spacer, 1" long, 1/4" OD (cut into eight ~3/8" lengths)
2 x Small gate hooks (1" total length)
8 x Metal grommets
Scraps of leather

TOOLS:
Pencil and paper
Ruler
Compass
Utility knife
Glue (water-soluble)
Hack saw
Metal files
Sand paper
Drill press (or hand drill) and assorted drill bits
Pliers

1a: Using paper, pencil, ruler, and compass, draw and cut out four guides in the shapes of the arms (two right arms and two left arms - they are not exactly identical).

1b: Glue the guides to the flat aluminum stock.

1c: Cut arms to size, cut and file the teeth, cut and file yarn notches, and drill holes.

2a: Cut the square tubing to size and mark arm slots.  (NB: Remember that arm slots at one end of the niddy-noddy will be perpendicular to the arm slots at the opposite end.)  Drill a row of closely-spaced holes along the center line.  Mark and drill holes for the machine screws that will anchor the arms.

2b: File arm slots to size, ensuring the arms can clear the tubing sides.

3a: Mark and cut two leather pieces to reinforce the niddy-noddy arms and cover the latch mechanism.

3b: Apply grommets according to package directions.

4a: For one pair of arms, insert a plain cotter pin into one arm and a cotter pin attached to a hook into the other arm.  Repeat for the second pair of arms.

4b: Bend and trim the cotter pins to secure them once in position.

Attach one arm to the body a machine screw. 

Long version: Place a washer on one machine screw.  Slide the screw through one grommet on a leather piece.  Insert the machine screw partially through one of the holes on the square tubing.  Slide one nylon spacer over the machine screw.  Insert the arm through the slot in the side of the tubing and line up the hole with the machine screw.  Place the second nylon spacer between the arm and the other side of the tubing and push the machine screw through (it should be pretty snug - needle-nose pliers help).  Fold the leather over the top of the tubing and slide the opposite grommet over the machine screw.  Secure with a cap nut.  Repeat with remaining arms, making sure to align the teeth appropriately.

Give all of the edges a thorough buffing with fine-grit sand paper to remove anything that might snag the yarn.  Clean off any grit or metal dust that may have accumulated and admire your fine niddy-noddy.

7a: To use, raise the arms and latch into place by securing the hook over the cotter pin.  Cover with the leather cap and secure in place with a cap nut.  Repeat for other end.

7b: To remove a hank of yarn, reverse the above steps.

7c: Unscrew the cap nuts and lift leather flap.

7d: Lift hook and lower arms to release the tension on the wrapped yarn.