PCC's A-AA2 (2nd. Annual BLF Scratch Made Light Contest)

I had all kinds of elaborate plans to make a modern day LED equivalent to the old Surefire 9N/9AN then realized that, while I could pull it off, it’s not unique. Then I thought about something that’s been rattling around in my head for awhile that I’ve wanted to make better, the A-AA. My first attempt at this light works, but, is huge for a single mode AA light. I’ll be combining traditional machining techniques with unusual materials to make a battery vampire light to drain Alkaline AA cells (hence the A-AA name, this being the second iteration, it’s A-AA2). It’s an entirely new design compared to the original A-AA.

So, why make this light? I hate wasting alkaline cells that still have some charge, but, are tossed because of the fear of a leaking battery. How about a light that is made with the intent to have batteries leak in them? If one does, remove the head and tail, wipe the body clean, wipe the contacts clean, hit them with sandpaper if needed, reassemble, put a different cell in and away you go.

So, follow along as I take pieces of aluminum, brass, acrylic, and some other bits to make a long lasting single mode battery drainer that can be cleaned up after a cell leaks in it.

4/19/14 update
Most of the raw materials needed to make this light
From the upper left to bottom, left to right - wquiles Joule Thief driver, XP-E, 17mm reflector, V10 glow powder, assorted O-rings, 5/8” brass rod, 3/4” clear acrylic rod, 7/8” clear acrylic rod, 3/4” 7075 T6 aluminmum rod, 1” 6061 T6 aluminum rod

My lathe - Speedway something or other

My mill - Sherline 5410

I decided to start with the tailcap since this is easier to make than the head and the body should be done last.

First, chuck the 3/4” 7075 in the lathe

Face the end

Lightly turn down the outside

Turn down the threaded portion

Cut it down to the target diameter of 16mm

Using the threading cutter, debur the sharp edges

Cut a groove where the threads are going to end

At this point I didn’t like the amount of threads that I was going to end up with so I decided to cut the shoulder back and give it more threads

Cut a new groove for where the threads are going to end

Using the parting tool, cut a groove for the O-ring and install it

Cut threads

The setup for drilling out the tailcap

Starting the drilling with a centering drill bit

Moving on to a 1/8” drill bit then a 1/4” bit and eventually the 3/8” bit going only 9/16” deep

Chucked a 3/8” end mill in the drill chuck and squared off the corners inside the hole since the drill bits leave an angled hole bottom

The next three operations use three M10X1 taps, the first being a standard tap, the second being a modified one that is almost bottoming, followed by a bottoming tap. Only about three threads are cut

Using the parting tool, start parting, but, stop after a few millimeters

Reinstall the turning cutter and rotate it 15 degrees to put the cutting edge at a 45 degree angle

Cut a 45 degree bevel then finish parting the tailcap

Remove the 3/4” aluminum and chuck the 5/8” brass then center it

After a quick facing operation turn it down to 10mm then cut half of it to 3/8” diameter, about 9.4mm

The tailcap slides onto the narrower part, but, not the wider part

Cut a groove to differentiate the two parts I’m making. There are two retaining rings being made

Using the center drill again, start a hole, followed by a 1/8” drill then a 7/32” drill

Using a 1/4”X20TPI tap, tap the hole

Part off the internally threaded retaining ring

Using the centering drill, clean up the edge so that the drill bit goes in straight

Using the threading cutter, bevel the hard shoulder for clearance before threading

The tailcap threads onto it

Part it off

Rechuck the brass about 7/8” further out, face it then turn it down

The left-most part is cut to 14.5mm. The right part will be cut down to 1/4”

The externally threaded retaining ring slides right on

Mark where I want the threads to end and thread it to 1/4”X20TPI

The internally threaded retaining ring screws on

Taking advantage of the handy retaining ring holder, I cleaned up the flash left from parting

The relationship of the three brass parts and how the tailcap attaches

Bevel the sharp edge

Next, cut a groove for the O-ring using the parting tool and install it

Using the turning cutter, cut a bevel

Part it off

The plunger assembly assembled. The internally threaded retaining ring is screwed on using Loktite

Reposition the mill head assemby at 60 degrees, install the tailcap in the four jaw chuck, then center it on the Y axis

One notch every 60 degrees

Reposition the mill head assembly at 30 degrees, rotate the tailcap 30 degrees and cut another series of notches 60 degrees apart

Remove the chuck from the mill and attach it on the lathe, tailcap and all

Face the tailcap. Shiny finish

Cut grooves into the face of the tailcap

Ready to assemble, but, the spring is too long

Tailcap assembled showing the fully extended length and the compressed length

After the last picture was taken I adjusted the spring length and that allowed the plunger assembly to have a longer travel, about 1/8”.

Tomorrow, the head…

4/21 update
After giving it some thought I had realized that I had made a mistake: the diameter of the aluminum tailcap is too close to the diameter of the O-ring and the O-ring will contact the threads of the body. To test this I took a scrap of acrylic rod and made a piece that will mimic the flashlight body. Additionally, I made this because the head is going to use the same exact threads so that the body is reversible.

The scrap acrylic

Chucked in the lathe and faced

Drilled it, first with the center drill then with a 1/2” bit

Using the small boring bar, opened it up to 15.0mm

Cut threads until the head fit (removed the plunger assembly for fitting)

Cut off the end of the threads for the O-ring and flare the end to allow the O-ring to slide in

Just as I had suspected, the plunger is too large and the O-ring groove is not deep enough. You can see that I’m putting pressure onto the tailcap trying to force it into the body and it’s not going.

The plunger itself needs to be redone so it’s not a total loss. The remaining pieces can be reused. Since the steps to make the replacement plunger are essentially the same, just using different dimensions, I won’t document it here. Needless to say, I’ll be using a smaller O-ring in addition to the plunger with a smaller diameter. Flying by the seat of the pants has its ups and downs…

4/24/2014 Update

Finished the plunger. It now works the way I had wanted it to.

Picture shows the finished tailcap, the slug of 1 1/8” 7075 T6 scrap that I found, and the temporary piece to test the threading of the head and tail. Mind you, this scrap piece was what was in the chuck while making something else and that other part was finished, leaving this piece of aluminum.

The aluminum is installed in the centering four-jaw chuck that was installed in the lathe. The saw marks on the back of the slug needs to be cleaned up.

It didn’t need to be completely cleaned up just yet. The small contact area where the chuck holds the piece had me worried that the piece would pop out of the chuck so I cleaned it up with skimming cuts and it took quite a few passes to get to this stage and I wanted to cut the other side to get more contact area

Reversed the piece and started removing material. I centered it around the smaller diameter part

Using the threading cutter, removing the sharp edges

Now that there’s a longer shoulder for the chuck to grab onto I flipped the part again and turned down the outside to match the diameters then turned it down further to 22.7mm. The target diameter is going to be 22.2mm, which coincides with 7/8”

Now that the diameter is closer to where I want it to be, I can finally finish facing it

Rotate the facing tool 45 degrees and cut a bevel

This is as far as I was able to get to today. Tomorrow I should be able to start the pocket for the reflector and emitter. The other end still needs to have the diameter reduced to 16mm, the 0-ring groove cut, threads cut, and the pocket for the driver. After that the positive contact and some other things made to get the head finished.

So, post #1 is still blank. Doesn’t look like I’m getting any traction on the light this week because work has been really busy and my kids have all kinds of activities after school that just takes up more of my time. After dinner I’m so tired I can’t think of sitting in a cold garage to work on this so it’s just going to have to wait. My next day off is Friday and I’ve got car maintenance to deal with. If I get the oil changed and the tires rotated in time I might start on this light.

No stress. I reckon this is why OL extended the build time allowed from last year. My shed is out of bounds at the moment and I'm still unsure what to build.

Make that 3 of us PCC. Finally finished my taxes last night and got home repairs starting to move up the priority list. Anytime spare time I've had has gone to trying to finish the my T90. I just have to finish that before I start something new. We'll get there, hopefully.

Well, Mother Nature has other plans for tomorrow and rain is in the forecast. I might just risk catching the flu by doing only the tire rotation. That should leave me enough time to whip up a tail cap or something if I don’t cough up a lung…

Got the tires rotated and decided to skip the oil change for now. Started on this build, spent the better part of the day working on the tail cap only to find that I made the inside diameter of the cap too small. Grrr! Back to square one. Will need to start with larger diameter stock.

See Post 2 for updates

Fantastic thread.. Great to see the build step by step.

Keep up the good work!

Cool design on the tail cap and plunger. Even with all the pics it took me awhile to figure out the sliding nature of it.

Nice going, man!

Funny thing is, as I sat down to make this thing, I was planning on making it just a fixed length tailcap, but, I thought about the complexity of the head and adding the plunger to that end would have made it huge. As I was turning the diameter down for the threaded portion I came up with the idea for the plunger and how it goes together. How’s that for doing things in real time?

Thank you for the many pics and the tailcap design is really great. I hope you will make some great pictures of the tailcap at the endpresentation of the flashlight in a few weeks :)

That is some really excellent lathe and mill work! Really outstanding!

Keep the lathe pictures coming, I never get bored seeing them :-)

A great flashlight in the making!

Very nice !

A self centering 3 jaws chuck would save you a lot of setup time for this concentric kind of work, you can have a decent one for surprisingly little money in this size.

Thanks, folks! I’m taking an off day today because I’m not feeling well. Woke up with a headache that won’t go away.

The lathe came with one, but, the runout on the thing is horrendous.

Enjoy the nap(or were you really watching the Giants?).

I should’ve taken a nap. Headache is still here. Don’t feel like taking aspirin, though I probably should. Didn’t watch the Giants. Did they win?

Yup, Posey homered and Lincecum got the W.