The 4th Annual BLF / O-L Contest; MtnDon's Entry, Hand Made Class

Cool, you can pick up some efficiency by sticking a reflector in the donut. Anything that fits will recover energy lost into the wood. I think your right about end/side grain. To stay round the wood can’t wobble and the cutting surface(rasp, sandpaper, whatever) has to be fixed. At least that’s been my experience. Threads also seem to grab unevenly in the chuck so I use a carriage bolt with the end removed. Sometimes I’ll press a bushing into the table but that can be a false security and may or may not put more pressure on the chuck.

If I have time tonight I’ll try it in the darkened shop with
(a.) the spacer as is now
(b.) the spacer with an OP reflector from an S2… it fits the hole and thickness of the board used
(c.) no spacer, dome right over the led.

I dug out my old Sekonic L28C2 photo light meter… really old school thing. (That dates me I think… :laughing: ) A selenium cell and analog meter. I have no idea if it will be able to discern differences at the light levels I intend.

Wow! I do wish I had a modern digital lux meter. I think that will be the next thing I buy. I’ll have to do a search on the topic of what’s good.

My old Sekonic analog meter showed the best output to be without any spacer and the dome placed directly over the emitter/mcpcb, listed above as setup (c.).

With setup (a.), the spacer in place but no reflector, the output was noticeably lower. In photographic terms there was slightly more than 1.5 f-stops less light, measured at the same point and distance from the dome.

With setup (b.), the Convoy S2 reflector inserted in the spacer center hole, the output was almost as good as with no spacer at all. Maybe only 1/4 f-stop less than no spacer at all, setup (c.). Considering that I have other reasons for the use of a spacer I believe this is the direction I will take. I used a small plastic “washer” under the reflector to insulate the reflector from the mcpcb.

I may do some further tests with a different reflector I have from an old mini-maglite and with changing the height of the reflector or perhaps the spacer thickness. But that will have to wait a bit.

Thanks to RFD for affirming that photons may be getting lost due to the wood spacer.

Interesting project. Remote Phosphor was a new one on me. Always good to learn something new.

No spacer should be the brightest. Next the spacer with a reflector in it. The wood will definitely absorb light.

Some more prototyping…

First, for those who don’t know and want to know, a forstner bit is made to drill a flat bottom hle in wood. This is one…

I need a cell holder. Here’s my first idea/attempt. The layout on a glued up piece of pine. This is a first prototype. I intend to use hardwood for the final.

Here it is drilled and cut to rough size. Drilled with drill press and corners cut using a cut off / mitre saw

I neglected to take in between shots for this prototype. For the final I will remember! I used a coarse hand rasp, then a finer one. The final version will be taller or perhaps an upper and a lower disc with dowel or tubing separators.

The block and cells do fit through the neck of the mug…

… more later…

Now thats different. I’ll be sure to check the bottom of my cup when I drop in for a drink. :+1:

Cool! It seems likely you could fit a fifth cell in unless you’re planning a 2S2P arrangement.

Not quite enough space for a centered fifth with the size restraints caused by the mug neck inside diameter. There’d be no wood left to hold things together.

Love the design, way outside the box! BTW, what is that little power supply?

Found it on ebay a while back. Search for “Mini Programmable Adjustable Digital Regulated Power Supply ” or something like that. For my flashlight needs I power it with a 30 year old TripLite 12 volt 10 amp benchtop power supply. The “MPADRPS” can put out amps but needs some fan cooling to sustain that. ….another little project that needs doing…. There may be better ones, but I only paid $20 probably a year ago.

Did some more today. I forgot myself and had glued up and begun to cut the cell block and missed taking some photos. :frowning: The block I believe I’ll be using started out glued up like this one. Except the one I used is maple, padauk and walnut, whereas the light colored wood here is red oak. The orange wood grows like that. It is african. Walnut is from a friend’s farm in VA and the maple is a left over from a 25 year old table project. never throw much out.

This is the one I am using. I cut the pieces mainly using the mitre saw. First I cut it to a square, more or less, then an octogon as shown. I end up with lots of cool little shapes of the different woods.

Then it was to a vice.

I began rounding off the sharp corners with a coarse wood rasp.

After a while it was somewhat more cylindrical

Next a switch to a finer toothed rasp/wood file

Much better, but only close…

Yes, that is me hand filing and using the camera self timer

Once the shape was close to what I wanted i also filed lengthwise to try and get the best cylindrical shape

This is a better fit than the first pine prototype.

This is a great project to watch! I’m sure the final lantern will be very nice, but even watching the making off is already a great pleasure.

Carry on please! :slight_smile:

Never crossed my mind but the mug handle is just like the old 6V lantern cell flashlights. Pretty obvious when someone else thinks of it. :person_facepalming: Good job! From here you could go with a tail standing area light as you planned or throw in your choice of reflectors behind the mason jar lid or both as so many “emergency lights” do.

Looking good Don. :+1:

The cells need a contact plate for both ends. This is the plate that will service the bottom end which will be the positive + ends of the cells. I cut the plate from a strip of 2” wide, 0.010” brass. The raised contacts are brass 4-40 machine nuts. Soldering them in place was tricky as they kept sliding about. I used them as the design is to use some of the many flat top cells I have on hand. Heat damage to the oak scrap from using a butane torch for heat.

… another shot including the cell block. The W. denotes the section that covers the walnut wood segment.

A view of the cell slot end with the plate held in trial placement.

More to come, thanks for looking.

You have literally gone nuts on this build. :stuck_out_tongue:

:laughing: :wink:

I like where this build is going. :+1:

After dinner I headed back to the shop. It occurred to me there was a simple means to prevent those brass nuts from moving about when soldering. I drilled through the plate and threaded steel machine screws into the brass nuts. The black steel won’tstick with the solder. This helped retain the nuts when I heated for one more solder joint, to come.

Side / edge view of the brass plate, steel screws and brass nuts…

Hole drilled through brass plate center. A clearance hole. Tinned the brass with a little solder for the next step.

A small Omten reverse clicky switch is to be used…

One switch contact gets soldered directly to the brass plate. The other end has a length of 18 ga. silicon insulated wire soldered to it.

I drilled through the center length of the cell block with a long 3/16” bit. This is for a wire.

Drilled through and centered quite well where it exited the other end. As I was drilling the drill shavings were a nice mix of white and red.

The wire is passed through the clearance hole in the brass plate. A double set of heat shrink tubing provides insulation. The four 4-40 machine screws will be removed before the plate and cell block is assembled.

Below is the view of what will be the bottom end of the cell block. Switch in place although I’ll likely use a small piece of 3M double sided tape between switch and brass plate. Or I could use cyanoacrylate, but that would make it more difficult to mod later.

Here’s the cell block with 4 x 18650 cells trial fitted. The cell block needs to be shortened a little, which will happen another day.

Thanks to all for the encouragement!! :slight_smile:

Looking good, you thought of tapping screws before I could mention it.