MtnDon's 12th Annual BLF Old Lumens Challenge Entry - Hand Made Category

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On to the cell holder. The 16650 cell will be removable, without the need for any tools. A length of 19mm OD copper tube will be the main holder. It will be supported by a wood cradle. I drilled 19mm holes into some wood blocks and cut a few pieces before I was able to drill through the wood block length without too much bit drift.

The 19mm OD tube fits in the cradle, though at present the cradle is too wide to fit inside the aluminum body tube.

The 19mm OD copper tube is also slightly too wide to simply slide into the ¾” width of the aluminum tube. So two flats were sanded into the copper tube side, using the belt sander.

I sanded down the sides of the cradle to make it fit inside the ¾” available space inside the rectangular tube.

The bottom of the wood cradle was sanded to align the height of the 19mm OD tube with the driver mount.

The cradle and cell holder parts

Here’s how they fit into the body tube… Once I am ready to assemble the carrier unit the cradle will be screwed or glued to the main bottom copper strip of the carrier. As well the 19mm OD tube will be glued to the cradle.

Before I can progress any further with the cell holder and carrier I need to make the rear tube plug, which will permit the cell to be changed. The plug will be made from 17mm copper tube. I started by silver soldering a piece of copper sheet to the end of the 17mm copper tube. Then the end was roughly trimmed using sheet metal shears.

The tube end was then sanded to make the capped end round.

The capped end was cut off the longer length of copper tube.

A small brass button was silver soldered to the side of that short capped tube.

The capped end was re-positioned in the clamp and a spring soldered to the flat cap. I used 138 degree C Sn42/Bi58 T4 solder paste to attach the spring. For heat I used the iron from my soldering station with a thick wide chisel tip.

Here’s one end of the 19mm copper tube, clamped in my wood clamp blocks. A slot was cut in the end using a Dremel tool. The slot was widened and the cut smoothed with a small file. This is making a bayonet fitting to secure the tailcap or plug.

Here we have the tailplug inserted with the side button slid into the cut slot.

The Dremel tool was used again to cut more slot at a right angle to the first slot.

I did not have a dowel that would be a proper fit inside the tailplug fitting. This is to make a finger grip for insertion, turning of and removal of the tailplug. Rummaging around my boxes of “stuff too good to throw out” I found a dowel that would fit inside a copper tube which would fit inside the 17mm copper tube.

Here we have the 19mm OD cell carrier tube lined up with the tailplug piece, a filler tube and the ½” OD wood dowel, in the order they will be assembled and used.

I drilled a hole into the side of the assembled plug unit. A wood screw is used to secure the parts together.

Next here is the bayonet unit; 19mm OD tube on the left and 17mm OD tailplug on the right…

The tailplug trial fit. There is a slight notch filed into the slot end on the 19mm tube. Tis is to act as a catch for the tailplug when inserted.

Next we have the cell carrier parts arranged as they are to be used.

That is all for now. Thanks for dropping by.

10 Thanks
22

Great!

Am really enjoying this build of yours!

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Back to the body tube. I need a lens for the front end. I plan on using a Carclo optic and want a flat “lens” covering and protecting the optic and keeping dirt out. I used some Lexan I had and cut a piece slightly larger than the ¾ x 1-1/4 open end of the aluminum tube. Then, I sanded it down so it was a good fit inside the rectangular tube. The lens will be glued inside the front end of the body tube later.

This extruded aluminum tube does not have as smooth a mill finish as I have seen of other extrusions. But that is what I have, so we have to work with what we have. As well the flat sides of the tube were not perfectly flat as the sanding revealed. I began smoothing the sides with the bench mount belt sander. First with a 240 grit and then a 400 grit. In the next image the aluminum tube in the foreground is the one I am preparing for use in this project. The other tube will be left in its raw state for comparison.

After the belt sander I switched to an orbital disc sander. I worked through several grits; from 800 to 1200, to 1500, then 2000 and finally 3000. The sandpaper was the wet-or-dry type. The sander is cordless. So I kept the material wet/damp by pausing the sanding every so often and swishing the aluminum in a water tub. The difference between the sanded and non-sanded extrusions is readily apparent.

Here’s the water tub with the water blackened from the sanding fines. The discs were hole punched but of course with the wet sanding there is no dust to be extracted through the holes. The sander suction is not great enough to draw water up which is very good.

After the 3000 grit I washed and dried the aluminum tube. I then got a bar of red rouge and my Ryobi flex shaft dremel-like rotary tool. Using a 1 inch diameter buffing wheel I began to polish the aluminum. After the red rouge was cleaned off I switched to Mothers Mag & Aluminum Polish with a new polishing wheel. After more tedium I washed off the aluminum tube and made the next comparison image.

I’ll take this moment to mention that I do not intend to polish the entire side width of the flat surfaces to a mirror finish. There will be some skins, or scales fitted for the final finish. I will be concentrating on obtaining as good a polished finish as I can on the 3/16” (4 to 5mm) or so that is adjacent to the edges and corners.

Next was some more work on the switch pushrod assembly. I glued the wood guide block to the top of the copper tube driver mount. I used a couple of drops of medium Starbond CA…

I clamped the assembly to allow the CA to cure.

The lexan lens has a layer of painters tape on each side for temporary protection. The wood spacer between the lexan and the copper carrier is the same thickness as the combined thickness of the mcpcb and Carclo optic. The lexan and spacer are held in place with double sided sticky tape.

The temporarily assembled carrier was test-fitted inside the body tube.

Measurements were made. Then double checked. A hole was drilled in the top of the body tube where the switch pushrod will extend through. There will be a silicone switch boot covering the end of the pushrod.

That operation worked out okay. I test-fitted the carrer and the pushrod and it appears everything will line up and function. Phew!

I polished the front end of the copper carrier where the mcpcb will be mounted. The solder joint at the bottom will be mostly hidden by the mcpcb and the optic.

That is all for a few days. Thanks for having a look.

7 Thanks
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Wow, that is some impressive work and I like how the aluminum tube turned out!

I’m curious to see how you glue the Lexan lens/window in place.

1 Thank
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In the past I have used a clear UV cured glue for gluing lexan to metal. I’ve also used CA with accelerator.

The biggest issue with UV cured glue and lexan is that lexan blocks UV rays, so the glue works best as a fine fillet where the lexan butts against the metal as long as UV light can be aimed directly at the glue, not through the lexan. CA’s drawback is that with metal it works best if the surface is roughed up. I haven’t yet checked if the UV cure glue I have is still effective. I have lots of CA on hand though and I know it is good. (Kept refrigerated, not frozen, CA can be stored up to 30 months. )

3 Thanks
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The UV stuff was my first thought as well, but if I may offer an idea, :slight_smile:

If it was me I’d just run a bead of good silicone around it after its in place. Both sides if you will have access to the back. Either a household construction type all weather caulking, or the automotive RTV kind. Depending how much UV or chemical resistance you want, or color you want. A fine bead of high temp black RTV would look great, and hold it in there well(designed to stick to metal engine parts too so no problem with the aluminum).

I’ve put several plexiglass windows in things with just a good silicone caulk as adheasive, cant imagine lexan would be much different.

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Silicone has crossed my mind. I have used it for window and door trim. The main thing holding me back is how to apply a good, smooth bead. ??? Maybe I need to practise with scraps?

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Yes practice helps immensely! I get too much of that lol. I can put the stuff on around windows and door trim, and ,well, almost anywhere in my sleep lol, I forget that not everyone does it for a living and has that steady hand.

but even I’d be running a bead, maybe 3/32" at the max, less better(and theres the trick, not cutting too much off the nozzle) “smooshed” out as well as can, them lightly smoothing it out with a finger, or something for a tiny spatuala maybe(maybe wet either with water depending on the effect you want), to get a nice even fade of caulk… if that makes sense. So a steady bead to begin with is far less critical.

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Yeah, when I do it, it looks like I did it in my sleep… :smiling_imp: :stuck_out_tongue:

2 Thanks
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I secured the driver into the mount with two small blobs of solder. I applied Sn42/Bi58 solder paste onto the negative driver rim and copper mount interface. Using the soldering iron with a broad and heavy tip I applied heat. It only took a few seconds for the paste bubble and melt. Voila, the driver is secured to the mount. I also soldered a black wire to the side of the mount ring. More will be shown on this in a moment.

The MCPCB I have has two flats. A very light sanding on those flats allowed the MCPCB to slide inside the aluminum tube. I would have preferred a different orientation to the triple LEDs but this is acceptable. In the past I have found that on occasion too much sanding or filing on a MCPCB can lead to problems.

Using a couple of small wood blocks I spaced the MCPCB away from the copper carrier. Once the positive and negative wires were soldered the blocks were removed and two strips of double sided thermal tape were applied to the carrier under the MCPCB. The MCPCB was then affixed to the carrier with the tape. I still need to clean the face of the MCPCB, even though the flux residue is the “safe” variety.

I used the SN42/Bi58 low temperature solder paste for soldering the black negative circuit wire. It makes soldering to large pieces of copper much easier.

I figured this was a good time to see if the assembled parts would produce light and to check if the switch pushrod was functional. I lined up the parts with the cell inserted and pushed them together to make the circuit path complete. A tap of the switch pushrod provided proof of light. Hoorah! The driver operated as expected.

The optic was temporarily fitted to the MCPCB. The carrier assembly was then slipped into the aluminum tube from the front of the tube. As already known, the optic is too large to be inserted inside the rectangular aluminum tube. The sides will have to be sanded a little.

I marked the areas to be sanded with a Sharpie and manually sanded the optic on 240 sandpaper. Two trial fits later the mounted optic fits inside the aluminum tube. Light is produced on demand! It is exciting to be able to see the “end of the road” is not too far off.

That is all today. Thanks for looking.

4 Thanks
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I secured the carrier assembly to the aluminum body tube with two 4-40 machine screws from the underside of the light. Two holes were drilled through the body and the copper carrier bottom. The copper carrier holes were tapped for the 4-40 screws.

It is time to attach the lexan front lens, or window, to the body. It would be great if the window could be removed and replaced but I have not come up with a method that I think will work well and look good. I have used a lexan window glued onto the exterior end of a similar aluminum tube before. That works but isn’t the most attractive look. I decided to do the window as an insert and use Kafuter UV cure glue. I have used it with success before and have some in the fridge that still works after 6 years storage. My UV light source is a Sofirn SF32UV.

I applied a small fillet of glue along the bottom edge first and set the glue with a couple minutes of UV exposure. Then I moved to the next side and repeated until all 4 sides were done. Pardon the dust on the lexan in the photo. The phone camera picks it up when I can’t see it with my eyes.

Next I moved to making the silicone boot fit into the aluminum body. In the photo the inner carrier assembly is inside the body. The top front pilot hole in the body was enlarged to allow the insertion of the switch boot. The switch boot will rest against the wood part of the carrier assembly.

Next it was time to make a pushrod that will work well with the silicone switch boot. The switch boots have a “nub” under the top of the cap. That needed to be removed to allow more depth for my pushrod assembly. The boots can be turned inside out on the end of a pencil for trimming. I used an Exacto knife for trimming.

I had planned on using that wood temporary pushrod as the basis for the permanent pushrod. However, I had an idea that I like better. I’m using a 4-40 machine bolt. The nut is turned on tightly. The nut and screw head fit nicely inside the underside of the switch boot. The overall length of the machine screw is 17mm. The switch boot is 8mm across the raised section. The bolt was ground to the final length and trial and error fitted to the light for easy smooth operation.

The switch boot fits the body hole snugly There is almost 1mm slack space between the underside of the boot and the screw head.

The switch boot is retained by an 18 gauge (1.6mm) copper strip, ¾” (20mm) wide. The copper also adds some bling to the light.

I marked, center-punched, drilled and tapped two holes for the 2-56 thread machine screws that will hold the copper strip in place. This makes it possible to remove the pushrod assembly to allow the carrier to be removed from the body. One never knows if that will be necessary at some point. Double stick tape or adhesive would have lent a neater appearance but I wanted to be able to repair or mod the light without damage.

Here’s what the top end looks like with the screws in place.

A close up of the boot area. The copper will be polished before the final assembly.

At the tail end of the light I cut off the extra length of the carrier bottom copper strip. I am adding a block to the rear end of the carrier. This will be used for mounting the tailboard. Trial fitted for now, the block will be epoxied to the copper cell tube.

I’m done for today. Thanks for looking.

1 Thank