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Step 2Ear Cup Assembly
The Ear Cup Assembly contains the pirated speaker and printed wiring board. It's made from the 1 1/2" (measured) copper cap and two bottle caps: one from an Excedrin bottle and the other from a common water bottle. You can find alternative cap sources, just make sure the larger one fits snuggly into the copper cap and the smaller one fits snuggly into the larger cap.
Using a hack saw, cut off about 7/16" from end of the 1 1/2" copper end cap. Drill a 1/8" hole dead center in the face of the cap. This hole will be used for the thumbscrew screw.
(Optional Step - to reduce weight) Measure and mark eight holes on the face of the cap, arranged in a circular pattern. Center punch and drill the 3/16" holes.
(Optional Step - to reduce weight) Mark out a pattern on the side of the cap and drill out the area. I mounted the cap on a piece of wood to use as a type of jig. I would drill then rotate the cap. Drill again and rotate and so forth. Do some filing and sanding to finish the holes.
Next drill four holes around the sides of the copper cap. The holes should be evenly spaced at the 12, 3, 6 and 9 o'clock positions. The holes should be 1/32" dia. Tap these holes with a 2-56 tap.
Next you'll need to add two swivel bosses on the ear cup. Cut two pieces of copper 1/8" tubing (1/4" OD) each about 5/32" long. Cut two pieces of 5/32" OD brass round tubing, each about 1/4" long. Deburr the parts. Sweat solder the smaller brass piece inside the larger copper piece. Contour the boss to fit the curvature of the cap. Sweat solder the newly made boss to the cap by using a 2-56 machines screw to hold it in place. Be careful not to solder the screw into the cap!
Swivel
Next fabricate the ear cup swivel. The swivel is made from a strip of 0.032 brass flat strip. First make a template from paper. Cut out a strip of paper and fit it from boss to boss, with a nice arc. On the template mark center points for the bosses and a point halfway between the two. Transfer the template to the brass flat strip. Using tin snips cut out a 3 7/16" by 3/8" wide strip. Drill the holes for the bosses and center hole 1/8" dia. The end holes of the swivel should fit over the brass bosses, not the copper portion.
(Optional Step - to reduce weight) Using a hand punch, make 3/16" holes evenly spaced.
To form the swivel, wrap it around a pipe. I used a sink drain pipe. Hand form it so it slips over the bosses. Of course, if you have access to a slip roller, that's the way to go.
Finish the swivel by filing and sanding it to a smooth burr free finish.I also had to make two washers for the boss since I couldn't find any number 2 brass washers. I made these from brass sheet and a hand punch. Number 4 brass flat washers will work but look a bit too large.
Finish off the swivel assembly by modifying a brass 8-32 acorn nut. Grind down the tip and drill through the top. Then use an 8-32 tap to create threads all the way through the acorn nut. You can skip this step by using a normal 8-32 nut but the acorn nut looks more finished. Then take a 1 1/2" long brass machine screw, thread it through the center of the swivel and lock it down with the modified acorn nut. Lastly, slip the swivel over the bosses. The swivel should rotate freely around the ear cup.
Speaker Housing
The speaker housing holds the speaker and circuit board. It also provides a surface to glue the ear padding (faux sheepskin).
The base of the speaker housing is a cap off of an Excedrin bottle. Cut a hole in the bottom that is slightly smaller than the diameter of the speaker. Then file down the outside of the cap to fit inside the copper ear cup assembly. Locate where the cable will exit and cut slots in both caps.
Fit the plastic cap from the water bottle inside the Excedrin cap. With a little whittling, mine simply snapped into place.
Before, you tapped 2-56 threads into four holes of the copper Ear Cup Assembly. These holes will be used to secure the speaker housing. Insert the Excedrin cap into the copper cap until the bottom is flush with the edge of the copper cap. Mark and drill the four holes in the Excedrin cap. Two of the holes will be held by the 3/8" long 2-56 machine screws used to retain the swivel.
The other remaining two holes will need to be secured with 1/4" long 2-56 machine screws which need to be shortened. The screws only need to penetrate the Excedrin bottle cap, not the water bottle cap.
Paint both caps with black paint.
Using a hack saw, cut off about 7/16" from end of the 1 1/2" copper end cap. Drill a 1/8" hole dead center in the face of the cap. This hole will be used for the thumbscrew screw.
(Optional Step - to reduce weight) Measure and mark eight holes on the face of the cap, arranged in a circular pattern. Center punch and drill the 3/16" holes.
(Optional Step - to reduce weight) Mark out a pattern on the side of the cap and drill out the area. I mounted the cap on a piece of wood to use as a type of jig. I would drill then rotate the cap. Drill again and rotate and so forth. Do some filing and sanding to finish the holes.
Next drill four holes around the sides of the copper cap. The holes should be evenly spaced at the 12, 3, 6 and 9 o'clock positions. The holes should be 1/32" dia. Tap these holes with a 2-56 tap.
Next you'll need to add two swivel bosses on the ear cup. Cut two pieces of copper 1/8" tubing (1/4" OD) each about 5/32" long. Cut two pieces of 5/32" OD brass round tubing, each about 1/4" long. Deburr the parts. Sweat solder the smaller brass piece inside the larger copper piece. Contour the boss to fit the curvature of the cap. Sweat solder the newly made boss to the cap by using a 2-56 machines screw to hold it in place. Be careful not to solder the screw into the cap!
Swivel
Next fabricate the ear cup swivel. The swivel is made from a strip of 0.032 brass flat strip. First make a template from paper. Cut out a strip of paper and fit it from boss to boss, with a nice arc. On the template mark center points for the bosses and a point halfway between the two. Transfer the template to the brass flat strip. Using tin snips cut out a 3 7/16" by 3/8" wide strip. Drill the holes for the bosses and center hole 1/8" dia. The end holes of the swivel should fit over the brass bosses, not the copper portion.
(Optional Step - to reduce weight) Using a hand punch, make 3/16" holes evenly spaced.
To form the swivel, wrap it around a pipe. I used a sink drain pipe. Hand form it so it slips over the bosses. Of course, if you have access to a slip roller, that's the way to go.
Finish the swivel by filing and sanding it to a smooth burr free finish.I also had to make two washers for the boss since I couldn't find any number 2 brass washers. I made these from brass sheet and a hand punch. Number 4 brass flat washers will work but look a bit too large.
Finish off the swivel assembly by modifying a brass 8-32 acorn nut. Grind down the tip and drill through the top. Then use an 8-32 tap to create threads all the way through the acorn nut. You can skip this step by using a normal 8-32 nut but the acorn nut looks more finished. Then take a 1 1/2" long brass machine screw, thread it through the center of the swivel and lock it down with the modified acorn nut. Lastly, slip the swivel over the bosses. The swivel should rotate freely around the ear cup.
Speaker Housing
The speaker housing holds the speaker and circuit board. It also provides a surface to glue the ear padding (faux sheepskin).
The base of the speaker housing is a cap off of an Excedrin bottle. Cut a hole in the bottom that is slightly smaller than the diameter of the speaker. Then file down the outside of the cap to fit inside the copper ear cup assembly. Locate where the cable will exit and cut slots in both caps.
Fit the plastic cap from the water bottle inside the Excedrin cap. With a little whittling, mine simply snapped into place.
Before, you tapped 2-56 threads into four holes of the copper Ear Cup Assembly. These holes will be used to secure the speaker housing. Insert the Excedrin cap into the copper cap until the bottom is flush with the edge of the copper cap. Mark and drill the four holes in the Excedrin cap. Two of the holes will be held by the 3/8" long 2-56 machine screws used to retain the swivel.
The other remaining two holes will need to be secured with 1/4" long 2-56 machine screws which need to be shortened. The screws only need to penetrate the Excedrin bottle cap, not the water bottle cap.
Paint both caps with black paint.
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