James C's 13th Old-Lumens challenge - Handmade

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This year I’d like to build a light. Wait, I’m getting ahead of myself… This year I’d like to finish an entry, preferably in the handmade category. For the past several years I’ve set out to complete a project for the contest but I’ve yet to finish one. This year will be different!

I have accumulated many modding parts over the last few years. I’m guilty of impulse-buying parts online with vague ideas of what I’ll use them for. Well, now it’s time to make a light - ideally without needing to buy anything.

After much deliberation, I plan to use some pieces of copper pipe, and a few off-the-shelf parts, to made a compact AA/14500 light.

Here is a general layout of the parts, from top to bottom:

  • Convoy T3 for reference.
  • 16mm ID, 18mm OD copper pipe (I’ll call this the outer tube).
  • 17mm TIR sold by Convoy, 16mm MCPCB, 16mm MCPCB for use as a shelf, “1/2 inch” (not exact) (actual 14.5mm ID, 15.9mm OD) copper pipe (I’ll call this the inner tube). I kept this pipe after re-plumbing my house. It’s from 1978.
  • 17mm driver. This one shown is a placeholder. I will likely use the one from the T3, which has no spring and supports both AA/14500.
  • 14500 for scale.
  • I think this is Convoy’s 15.8mm switch, copper spacer from 1/2" pipe, Convoy aluminum switch button.

General design:

  • The inner tube will have a shelf soldered onto the head end. It so happens a standard 16mm MCPCB is the perfect size for the shelf (though I wish it were thicker - I made double it up). It is the correct diameter and already has notches removed for the driver wires. I’ll simply sand-away the MCPCB’s solder mask down to the bare core.
  • Starting about 1cm down from the shelf, I will cut a notch out of the inner tube to place the driver, which will need its diameter reduced. The notch will remove much of the tube in this area. This will allow me to solder the driver’s normal body tube contact ring to the inner tube. This is hard to describe but I think it will work for retaining the driver and making electrical contact.
  • The end of the inner tube will have a bayonet-style connection for the separate tailcap.
  • The outer tube will be two separate pieces. For the head, a copper ring will be soldered on the end to act as a bezel to retain the TIR. The head portion will be long enough to cover the “driver notch” of the inner tube. Come final assembly time, I will glue this head portion of the outer tube to the inner tube.
  • The tailcap will house the switch spring and mechanism. The switch board, mechanism, and button are all within the ID of the outer tube. A small piece of outer tube will encase all of this and slide over the inner tube when the tailcap is installed. It will be retained by a bayonet-style system, i.e. two small nubs on the inside of the outer tube portion will fit into a channel cut into the inner tube. “Push on and twist” to lock on the tailcap.
  • Visually, the outer tube “head” will take up about 50% of the length. Roughly 20% in the middle area will be exposed inner tube. The outer tube tailcap will be the remaining 30%. The plan is to be roughly the same length as a T3, but smaller diameter.
  • I haven’t yet decided if I will install a clip. It would likely entail tapped holes in the tailcap.

Challenges / Concerns (so far, ha):

  • Though the inner and outer tubes have a pretty tight fit, I worry about thermal conductivity between the two tubes.
  • I don’t want this to look like plumbing parts thrown together, so I will experiment with ways to engrave / finish the copper.
  • I have never made a bayonet mount (or made an entire light like this, for that matter). I want the tailcap to install smoothly but not wiggle around in use.

I started the project a couple nights ago. So far I’ve cut some of the tubing, soldered on the bezel ring, and started on the tailcap. Soon I will make a post dedicated to the tailcap, as that’s the most interesting part so far.

Hopefully you’ll enjoy the build!

Edit: Closing remarks after completion. Feb 6th.

Now that I’m finished, I’m very pleased with how the light turned out. There are some parts I wish I had implemented better, but the light is perfectly functional and I’ll learn from these mistakes in future builds. In other words, I’m finished with this and looking forward to he next build! :slight_smile:

Tools used:

  • Simple hand-operated tubing cutter.
  • Handheld pipe deburring tool.
  • Rotary tool and several bits (cutting wheels, burrs, sanding wheels, etc.).
  • Various hand files.
  • Tap, tap holder.
  • Drill press and handheld powered drill.
  • CA glue, UV epoxy.
  • Soldering iron.
  • Heat gun (large type typically used for paint removal).
  • Hotplate.
  • Bandsaw (for making jigs / fixtures).
  • The driver, TIR, LED (I went with XPL-Hi 3000K), MCPCB, pocket clip, switch board/spring, (replacement) switch mechanism, and switch boot were all parts I had on hand. I think they all came from Convoy, actually. Well, other than the old 4Sevens driver. The screws and washers came from AE.

I did very little design work, sometimes to my disadvantage. Once I figured out the two sizes of copper tubing fit together so well I knew this would drive my design, e.g. an AA battery perfectly fit in the smaller tube, thus this would be an AA light.

My takeaways:

  • The bayonet mount for the tailcap worked surprisingly well. Granted, it’s not water resistant at all, and I may have gotten lucky with everything lining up correctly.
  • Soldering the washers on the head and tail gave me more frustration than I expected. Part of this was due to the washers being ever so slightly undersized on their OD for the tubing. If they were oversized I could have trimmed them down to the tubing post-soldering, though getting the alignment correct for the ID would still be a challenge. I tried to think of some kind of jig for alignment when soldering but didn’t find a solution.
  • My eventual technique of cutting slits in the tubing for the driver and switch board and soldering them to the thin “arms” worked well. Retaining these two components was a concern of mine since I lack the ability to make threaded retaining rings.
  • In total this project took maybe 6-8 hours. If I were to make it again it would probably take under two hours.

Ok, I think I’ve said enough though I’m more than happy to answer any questions. I’d like to give a big thanks to the organizers of the contest. This was a lot of fun, building my own project and following along with others’, and I hope to do it again next year!

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The 13th Annual Old-Lumens challenge- 2025- Official thread- Winners announced!!!!
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Very cool!

Regarding the etching, I’d consider chemical etching - copper is very reactive - you could mask off an area and choose your poison. Just an idea!

Cheers!

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Thanks for the suggestion! I hadn’t considered masking off an area for etching. I have a laser engraver that I could use to create the mask design, though I would have to make sure that doesn’t put me in the machine made category.

At the very least I will probably force patina some of the pieces. I like the contrast of a very dark patina and polished copper.

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You could probably x-acto an old vynyl sticker and apply that to the light for masking - depending on how complex the design/steady your hand is! I’d imagine bringing the machine out to do the cutting for you would bump you out of the handmade category (*but I don’t make the rules! I’m new here!)

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I made some progress recently. First, I made a design change. I decided the Convoy T3 driver wasn’t going to easily fit so I switched to an old Foursevens AA driver from a light I irreparably damaged while trying to open it up for an emitter swap. It’s an ok driver. It has low-medium-high without mode memory. It unofficially supports li-ion.

I notched-out a space for the driver in the body tube using a rotary tool with a cutoff wheel. The notch design is to allow a single piece of body tube to house both the driver and the LED shelf. The notch allows me to solder the driver to the body, thus making the needed electrical contact while holding the driver in place.

Note, the driver is not yet soldered to the tube and it’s not held in place so it’s sticking out a little in the pic. The cutout just below the driver is to remove thermal conductivity from the rest of the tube to make soldering easier when I get to that point.

Here’s another view. You can see most of the tube is removed in the driver area. The LED shelf is simply an upside-down 16mm MCPCB soldered to the body tube. I recently got my first hotplate which made soldering the shelf very easy! I previously would have used a heat gun (like for paint stripping).

I cleaned up the tube with some Brasso and a woven sanding wheel on the rotary tool. It’s the same tube as in the pic from my first post - big difference! I like the brushed look it has but I may end up trying to force a dark patina on this piece.

I’m preparing to do the tailcap next. I’m not too worried about the tailcap (I think I have a good plan and the hotplate will help a lot), but after that I’ll need to deal with the bayonette mount for the tailcap - thus the potential to mess up the body tube and all my progress.

More to come soon. As long as nothing goes wrong I should have no problem finishing on time this year! (fingers-crossed).

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This looks amazing!
Can I ask, did you remove the conductive layer from the mcpcb so that it was direct copper making contact with the tube

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Thank you. Yes, I sanded the MCPCB down to the bare copper substrate so it could be soldered to the tube. I placed a sheet of course sandpaper on a table then, holding the MCPCB down with finger pressure, sanded in a figure eight pattern.

Using the MCPCB as a shelf was one of those fortunate design solutions that work perfectly. It’s cheap and on-hand, the exact size needed, already had cutouts for wires, and the sanding was easy. If only the rest of the light design would be so lucky.

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Quick update - I’m glad the deadline was extended. I think I could have finished on time if I pushed it this last week but the extension relieved some pressure. I just don’t have much time for my hobbies these days.

I’ll do a more in-depth post with pictures, but I had some challenges with the tailcap over the last few work sessions. I overcame those and just finished coming up with a workaround for a new challenge involving the “studs” for the bayonete mount. I had planned to use very short pieces of copper wire but securing them was a problem. I now plan to use screws, but they’ll be sanded-down so they’re hardly visible.

I guess I’ll need to decide on an emitter soon. My only strong preference is it should be in the 3000K range to match the warmth of the copper. Going off memory, I think my options on-hand are:

  • SST-20
  • SFT-40
  • XPL Hi
  • XPP
  • 219B
  • 519A
  • LMP LHP531

What would you choose? I have a variety of 17mm TIRs from Convoy so odds are I can get a decent beam profile out of any of those LEDs.

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2700 K NTG35
dedomed 4000 K 519A
XP-L HI 7A3 from Simon

if 80 CRI is enough I would vote for 7A3 XP-L HI because of the really good tint (slightly below or on BBL)

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I’d like to try the NTG35, unfortunately I don’t have any and they wouldn’t arrive before the deadline.

Good choices with the other two. I do have a 519A 4000K dedomed that I hadn’t considered. Thanks!

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Tailcap. The tailcap gave me some challenges.

My first plan was to make the tailcap in two pieces - an inner “plug” and an outer “shell.”


In this pic, the plug would consist of the pieces on the top - a standard Convoy switch, piece of 1/2" copper, copper washer, and Convoy switch button. The bottom piece, the shell, is a piece of 16mm (ID) tube. The idea is the plug would fit into the shell. The shell would also have the “studs” for the bayonet mount (you can see I already drilled the holes for the studs).

In theory, this plan could have worked; however, I ran into some issues. The switch, in Convoy lights, is intended to be held to the tailcap with a retaining ring that makes electrical contact with that outer ring on the switch board. The switch mechanism (white piece on the back) completes the path between the spring and the body. The challenge for me was there is not a good place to solder the copper tube to the backside of the switch board. I attempted to solder between the switch component and the copper tube, but the thermal masses are very different and it was easy to damage the switch mechanism with excess heat when soldering.

I abandoned this design and instead tried to make more of a mechanical connection rather than relying on solder alone for strength.


Here’s the revised design for the inner plug piece. It has slits cut into it for sliding-in the switch board.


Here is the plug assembled. The switch board is slid into the slit and then soldered. Soldering was easy because of the small thermal mass of the “arms” on the spring side of the copper tube. These arms, while thin, are still strong enough to retain the switch board. I then used CA glue to adhere the switch button to the tube (that white, powdery-looking, substance around the button area is a side-effect of the CA glue activator I used).

With this revised design the copper washer is soldered to the outer shell of the switch. I’m still getting used to using my new hot plate. I’ve tried solder paste but getting consistent coverage has been challenging.


Here I’m trying 0.8mm rosin-core solder wire rather than paste. I first chamfered the ID of the tube with a deburring tool, then placed solder wire on it. Next, I flipped this over and placed it on top of the washer on the hot plate for soldering. This technique worked ok, but aligning the copper washer on the tube was an issue.


In this pic you can clearly see the washer is misaligned. I ended up redoing it.

Next, I’ll cover the bayonet mount. This was my last concern as I’d never done anything like it and I figured it could be challenging to make it function well.

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Bayonet mount for the tailcap.

First, I used my drill press to precisely drill two 2mm holes in the tailcap shell (you can clearly see one hole in the last pic of my last post). This would be for the “studs” on the bayonet mount. My initial plan was to use 12 ga copper wire (just over 2mm in diameter) as the studs. I tried press-fitting them but that didn’t work. Next, I explored soldering but there just wasn’t enough cross-section of tubing to make a secure solder joint that wouldn’t be obtrusive.

The solution was to tap the holes for 2.5mm diameter screws. Fortunately I have an assortment of small screws on hand (“laptop” screws from AE). In this pic you can see the screws have been shortened so as to not hit the battery as they pass through the “channels” of the bayonet mount. Also in that pic you can see the channel cut into the 1/2" battery tube.

I made the channel by placing the tailcap (before insertng those screws) over the battery tube and marking the tube via the stud holes. I gave it a small rotation and marked again. I then used a tiny cutting wheel on my rotary tool to connect the circles and complete the channel.

It may be dumb luck considering how many things needed to align correctly, but the bayonet mount works surprisingly well. Friction from the spring helps resist turning. It’s hard to tell in the pic, but I very slightly angled the horizontal portion of the channel cut to further prevent the tailcap from accidentally coming off.

Here is a pic of the outside of the stud screws ground down flush with the tailcap shell. Unfortunately some of the recess from the Phillips head remains, though you have to look pretty closely to really notice. BTW, I used CA glue on the scews to hopefully hold them in place - again, not much cross-section to the tubes for the threads to grab.

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Last few details.

The head tube is simply a piece of the 18mm OD tubing with a copper washer soldered onto the end. I used a 17mm, 45 deg pebbled TIR from Convoy. It had to be sanded-down to 16mm to fit in the head tube. The bezel, i.e. copper washer, gave me problems. I found it difficult to solder it on cleanly with little solder visible. Alignment was also challenging.

I wanted to maximize the effective diameter of the TIR so I had to make the bezel as small as possible while still retaining the optic. This meant reducing the diameter of the washer post-soldering. I rigged up my rotary tool clamped vertically to a table. I added some wooden guides and was able to use it sort of like an upside-down mill, albeit a very crude one.

This pic is looking straight down at the head piece standing bezel-down on the table. You can see the inside of the bezel (covered in excess solder). There’s a carbide burr offset from the middle of the tube. I first ensure the burr is touching the bezel, then I place a feeler gauge between the tube and the stop. When this spacer is removed, it allows me to push the tube into the burr until it hits the stop. Essentially, the feeler gauge spacer allows me to set the maximum amount of material removed. Yes, this is sketchy though probably not all that dangerous (the burr is sticking out of the table by 3mm or so). This technique worked reasonably well.

One of my goals was for this to not look like a few pieces of pipe thrown together as a flashlight. To me, that means I need to add some aesthetic elements. I had an idea for using a similar setup with the rotary tool for “precisely” engraving some designs into the head tube.


Here’s what I came up with. The head tube is sitting in an oddly-shaped piece of plywood I cut out. The tube cannot move side-to-side, but it can move back-and-forth (into the sanding drum). There are two small stops on the end of this plywood guide limiting how far the tube can move into the drum, i.e. limiting the amount of material removed. I spun the tube by hand to end up with three uniform notches. They serve no real function other than to perhaps make this look more like a flashlight and less like a piece of pipe.

Lastly, the clip. I got ahead of myself in putting the tailcap together and forgot to account for the clip. It would have been best to remove the tailcap plug before attempting to tap the clip’s screw holes in the shell of the tailcap. Unfortunately, after installing the bayonet screw studs and sanding them down (also glued), they were impossible to remove non-destructively. On the other end, the plug is retained by a washer soldered to the tailcap shell, thus I couldn’t remove the plug (desoldering the washer likely would have damaged the plug from the heat).


Fortunately, I had just barely enough wiggle room to push down the plug against the bayonet studs and make room for the tap. I got really lucky here. I should have planned my steps better.

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Finished! It’s far from perfect but I’m quite happy with it.

I’ll likely add some more commentary tomorrow if I have time, but I wanted to be sure to get this posted before the deadline. I took a short video of assembling it but I’m having trouble getting it uploaded to imgur. I’ll try again tomorrow.


Next to a couple other AA lights (L11C and Convoy T3 with modded shorter bezel).

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It looks great, good work! .

You still have a day or so to finish it up.

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That looks good, James. :+1:

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Here’s a video of assembly. Note, the head is currently held on by friction. I want to show it to a friend before I made it semi-permanently attached using CA glue.

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18

Fantastic craftsmanship, this light is gorgeous.

Might have to copy this at home

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Thank you! I’m quite pleased with how the light looks (other than the sloppy soldering on the tailcap and bezel in particular). I’m sure you could make a fantastic light with a similar approach.

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The 13th Annual Old-Lumens challenge- 2025, The Peoples Choice Award- Choose your favorite build!- Finished
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Congrats on the build of your copper flashlight James_C!

I’ve often thought about doing something similar with a copper pipe and parts, but you actually did it. I could feel your struggles as you navigated your way thru this mod. And adding the notches and a clip finished it off nicely.

It’s a really good looking flashlight and I’m sure it’ll look even better once the patina starts to kick in.

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