FmC's 2nd Annual Handmade Light Build; "The Hand Mortar" -It's done!!!- Updated daylight pics.

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FmC's Hand Mortar


More photos in post #61.
Final build photos at the end of post #5, with short video & comparison beam-shots.
(From Wikipedia)

"The hand mortar is a firearm that was used in the late 17th century and 18th century to throw fused grenades. The action was similar to a flintlock, matchlock, or wheellock firearm (depending on the date of production), but the barrel was short, usually less than 2 inches (5 cm) to 4 inches (10 cm) long (though some are reported to have barrels up to 13 inches (33 cm) long), and had a large bore to accommodate the grenade; usually between 2 and 2.5 inches (5 to 6 cm)."

I decided to go for a larger format this year - I knew I wanted to go MT-G2 with active cooling.

I've settled on a body style which I think is appropriate for this emitter, the Hand Mortar. The MT-G2, coupled with a big 100mm reflector, & plenty of Amps, will be able to 'lob' a big dollop of light wherever it's pointed!


Here's a glimpse of the 'business end' components that will be used;

Following the recent work that has been done with the diy-FET drivers, I really wanted to include one in this build, so I recently spent best part of a day wiring up a SOIC8 clip, installing the drivers & sw, modifying & flashing a driver, ready for a FET transplant.

Picture shows starting out with the SOIC wiring, to finally flashing the modded STAR firmware.

Update 17th June;

Too cold & dark to be in the shed tonight, so I came back inside to finish the re-programmed driver with the Zener & FET mods.

1st shot is of the driver, after stripping off the 7135's, & the new parts to be added to the board.

2nd shot is the back side of the board, with the Zener diode in place.

3rd shot is the topside, with resistor & FET added.

...tbc...

2

I started work on the heat-sink, & the first thing to do was to get rid of that bracket, which meant pressing the copper slug out;

This will also allow me to work on both the copper slug & the fin assembly individually, prior to pressing back together.

For the mortar barrel, I had trouble finding a suitable candidate, & almost settled on a fruit-salad tin which you will see in one of the later pictures.

I actually spent quite a bit of time on it, flaring the mouth of the can to make it look less like .....well.... a can-on-a-stick...

But I was not happy with it, & finally came across a more shapely 'barrel', in the form of a diesel fuel filter. I separated the seam with a grinder, then cut the center plate with a hacksaw blade, until I was able to pry out the internals;

Regular readers may spot the head of the "Black Maggot" checking out the progress in the top left of the last picture ;)

...Of course, the heat sink that fitted perfectly into the fruit-salad can is too big of a diameter to fit into the filter housing, so something had to be done about that...

The fin assembly was spun up in the drill press, & carefully 'kissed' with an angle grinder, until it was a snug fit inside the filter housing;

The cooling fan was also test-fitted at this stage;

Air will be drawn in through the rear, & exit through holes in the front section of the barrel, which I will make at a later stage.

3

Time to take stock of the situation....

I decided to use a fresh lump of Pine for the Stock, as it's cheap & easy to work with. I'll end up staining/varnishing it prior to final assembly.

I can't draw to save myself.... After several attempts at free-handing the outline of a Stock, I came up with a half-decent one;

The paper outline was stuck onto the Pine, & out came the hand saws;

At this stage, the Stock will only be rough-finished, as there will be quite a bit of handling fitting up the other components, drilling recesses, etc.

4

Time to focus some attention to the reflector & bezel assembly :)

The reflector did not have a hole for the emitter, but had a depression in the base that was easy to file away, & when tidied up, left a more than adequate hole for the 20mm Noctigon;

With the smaller diameter of the new barrel, the lip on the reflector had to be trimmed.

I free-handed it in the drill press as close as I dared, then finished it off with a file;

The reflector will be held in place by the bezel assembly, which I made by hand-forming some brazing rods on the back of the vise, along with a strip of copper, to a slightly larger diameter than the barrel;

First, one of the rods was soldered to the inside edge of the copper strip, with half of it protruding, in order to keep the rounded edge visible;

After the first joint was completed & the assembly trial-fitted, I repeated the process on the other side, praying that the whole thing didn't fly apart when re-heated....

Next up are some of my failed attempts to make a slick-looking clamp bolt which didn't work for various reasons, & then what I finally settled on.

At this stage, I'm not sure if the clamp will be on the top, incorporating a sight, or underneath, with some kind of ornamental piece attached to it;

tbc...

5

Finishing off the Pill/Heatsink assembly.

The copper slug was drilled & tapped for the Noctigon attachment. Fresh good quality drill bit & plenty of lube ensured that I didn't leave half of the bit snapped off in there...

The reflector fits over the whole LED assembly, flush with the pill. Because the reflector is not physically attached, the pill depth can be adjusted in the barrel to adjust the focus if necessary. The screws attaching the star sit just below the emitter die.

I will bring the LED power wires in from the side, rather than trying to drill through the full thickness of the copper pill.

OH NO! Disaster!!! I forgot to tighten the shelf on the drill press, & the bit dug in & swung the whole shelf around...

...It cleaned up OK - close call!!

Moving on, it's time to press the assembly back together. Because the alloy galled up a bit when I pressed it off, I cleaned up both the surfaces, & applied a little AA adhesive to fill any gaps, & also to help lubricate it during the press fit;

All lapped & ready to go.

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Meanwhile, back at the ranch, the stock needed some loving, as the cut-out for the original fruit-can barrel did not match the contour of the new one.

My wood working skills were about as sharp as my chisel, but I managed to re-work it to fit the new barrel;

I also made a strap out of copper to hold down the rear of the barrel. There is a counter-sunk screw on the underside of the stock which clamps down the front of the barrel.

Time to move on to the trigger area. I sanded up that area of the stock, & fashioned a trigger guard out of copper sheet. I picked up a pack of brass curtain hangers for 50c a few weeks back, & figured that I could cut a few up & fashion the trigger out of them.

The trigger mechanism is still a work-in-progress... ran out of daylight today, & may not be able to get much else done until next weekend...

I also started the cut-out in the stock for the trigger mechanism. I got a little further than this next pic, but you'll have to wait for the next installment....

14th June

Ok, weekends here, more progress;

The trigger will activate a push-rod mechanism, which works the reverse clicky switch.

The battery pack & switch will be an all-in-one unit, housed inside a cavity in the stock;

It took a while to get the cavity nice & even, so the battery pack fitted snugly, without getting stuck in there.

I had to bore another hole in the underside to clean up the cavity end, & make sure the push-rod & switch lined up.

To get a shallower angle for the push-rod, I ended up drilling from the rear of the stock through the battery cavity, with an extra-long drill that I made out of a length of welding rod.

The power pack was fashioned from some clip-together battery holders.

Work began on the electronics; assembling the switch, & adding resistance mods to the springs.

The power pack assembly is now complete, along with the end-cover that will screw to the rear of the stock, to hold everything in place, & complete the circuit;

I shifted focus back to the shiny bits for a while....

The local hardware store doesn't believe in flat-blade screws any more, & the phillips-heads are not exactly period-correct, so I filled in the slots & re-cut the flat with a hack saw.

While the torch was out, I also added a strap to the trigger guard to give it a little more depth & strength;

More to come tomorrow.....

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15th June


I started off today by boring the holes to take the wiring through to the front of the stock.

All of the wiring through to the front is 18awg, taken from an old PC PSU.

Once done, I wanted to test the circuit, & also the trigger operation for fine-tuning.

....I don't know if anyone picked up on my wiring boo-boo from the pictures yesterday....

Test voltage was 14.8v ....I had configured the power pack for 4s instead of 2s2p.

I was committed with the switch design & dimensions, so I had to re-wire the power pack.

The switch was easily re-configured by looping a wire around to join both the negative springs.

The copper end plate now becomes the positive end, with a wire running up through the center of the pack, which will go straight through to the driver & fan at the business end.

I had to use some automotive spade joiners to separate the wiring, to facilitate easy removal of the power pack in order to charge the cells;

Now that the voltage is good, I wanted to do a quick load test & Amp check.

I quickly re-flowed the MT-G2, as I could clearly see a gap between the LED & board.

After lapping, I used whisper of Arctic Ceramique, & attached it to the heat sink.

A test fire in mule-mode showed everything was working well. With the long jumper cables to the meter, & batteries fairly low, it was showing just under 4.5 Amps.

With the test fire complete, everything was stripped from the body, & a cavity for the driver was bored into the front of the stock.

With no more major work needed to be performed on the stock, I set about finishing off the contour, & started sanding in preparation for varnishing.

Saturday 21st update

The first coat of varnish was applied to the stock this morning - it will take until tomorrow to dry enough for a light sand & re-coat.

The rest of today was spent making a few more components, & cleaning up all of the copper & brass, ready for assembly.

Here's the stock as it looks now. The other parts are a plate made from a round plumbing joiner that will cover the wiring connections for the battery pack, & the front sight that was made from a few copper off cuts, filed square, & soldered to the front half of a .223 shell.

I'm thinking of using the rear half of the shell for the rear sight, but it will have to be mounted higher on the stock, so the brass screw that is currently soldered to it will have to go in lieu of something else. ....or I might just use something else altogether... We'll see what happens tomorrow!

Sunday 22nd update.

I sanded back the stock earlier today, & applied another coat of varnish. It was still a little too tacky to sand...damn cold weather... No point posting another pic of it now - looks the same as it did in the previous pic above.

I decided not to use the end of the .223 for the rear sight. The only action it's getting now is in this photo, to prop up the new sight that I made from a strip of copper. It will be bent & attached when the rest of the parts are on, in order to get the height correct.

The barrel still needed a little work; I cut the breather vents into the underside, & removed the red print with some thinners.

The light engine was installed in the barrel for the final time, & I set about looking for a lens. I had planned to pinch one from an old Dolphin torch, but that didn't work out, so I cut one from a thin sheet of clear plastic instead.

Last shot shows the completed barrel assembly, with front sight mounted.

All that is left to do now is wait for the varnish to dry, assemble the hardware, & join the wiring to the light engine.

June 25th Update

.....or so I thought. A combination of old varnish & cold weather (& maybe a little impatience) bit me. The varnish just didn't seem to be drying, & it needed sanding & re-coating again. It was like trying to sand bubble-gum... I made the best of it, & wiped it down with some turps, & finally got it smooth enough to have another go at varnishing.

Armed with some slightly-less-old varnish, & a new $2 brush, I was back in action. I applied a coat last night, & another tonight, & it's looking good.

Meanwhile, all of the shiny bits have been polished up, & I also made up a little plate to attach to the side of the stock. Some more brass shells were cut up & flattened, & some copper plates were cut, & I played with a few different designs. When I finally settled on one, I made some fake brass 'rivets' with a metal hole punch, & also used the punch to trim the corners on the copper plate. The rivet heads were then soldered to the copper plate.

Here's a pictorial of the process;

June 26th update & finished product!!

The following shows all of the pieces prior to assembly, & the final stage of the wiring.

When I was testing out the driver a few days ago, I was debating on how to hook up the fan. I didn't want it running all of the time, & didn't really want a separate switch. After a little probing, I found out that if the fan was attached to the PWM output, there was not enough juice to start it, unless it was on full output - perfect!

I slipped a length of shrink wrap over the wires, soldered it all up, covered the driver with the shrink wrap, & tucked it all back in the recess at the end of the stock.

And not too long after that, we have the finished product!

Indoor working shots - the camera was self-adjusting, so turbo looks lower than high.

For size comparison, the light that the Mortar is sitting on is a Convoy L4.

Here is a link to all of the pictures in Flickr, for those that are interested.

Short video of operation;

https://www.flickr.com/apps/video/stewart.swf

Beam shot comparison

I took the Mortar into work today to show the fellow workers, who all loved it :)

For comparison, I also brought in the following lights;

* HD2010 w/ XM-L2 U2-1A Original East92 driver, KK ICR 26650.

* Convoy L2 w/ XP-G2 R5 , de-domed, @ 5A

* C8 w/ MT-G2, modded 12*7135 Nanjg.

I'll show some mouse-overs for each light, comparing it with the beam of the Mortar.

"The Crow-Tree" - a little over 100 meters distance.

Mouse-over for HD2010

Mouse-over for L2

Mouse-over for C8 MT-G2

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The driveway

About 70 metes in length, with industrial sheds either side.

Mouse-over for HD2010

Mouse-over for L2

Mouse-over for C8 MT-G2

Overall, I think the reflector works really well with the MT-G2. I can't wait to get some hotter cells into this light - with the shots above, it has Samsung ICR 28A laptop pulls in it, & they were nowhere near fully charged, after me playing around with it last night for quite a while, & also earlier today with the workmates checking it out.... They each found turbo, heard the fan cut in, then shined it around for a while.... All of the other lights above had freshly charged cells in them.

Build Stats

Cost;

* MT-G2 - ~$20

* Length of Pine - ~$7

* New paint brush - ~$2

* Brass screws - ~$8

* Reflector - ~$3

The rest of the components I already had lying around.

Tools;

* Drill press

* Hydraulic press

* Grinder

* Hand drill

* Various files

* Hand saws (wood / metal)

* Tin-Snips

* Hole punch

* Engraver

* Cheap Butane torch

* Soldering Iron

* SOIC clip & AVR programmer for custom Nanjg driver

* Screw drivers

* Hand chisels

* Thread tap

* Hammer

Time Spent;

Invaluable! :)

Thanks for reading - it's been fun getting this thing together :)

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Any news?

8

Sorry for the lack of progress RBD… I’m right at the pointy-end of a separation, & my time & motivation is in short supply.

You must feel lonely doing all the work around here…. have you hit the 40:1 ratio yet? :wink:

Here’s a clue as to the format my build will take.

I know a lot of people opted in for the build comp. this time, & so far there is not a lot of progress to see - I’m hoping that it’s just the amount of time that was given, & things will heat up soon!

9

That would be cool. You can’t start with flashlight parts but you could certainly do a conversion of something else if making your own stock is too complicated. Even a conversion wound involve quite a bit of work.

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No - I’m going to make the stock from a lump of timber - that should be fairly easy. The trigger mechanism & barrel - not so easy!

11

Brass is much cheaper at the salvage yard and easily soldered & just a bit harder to braze(need a mapp torch minimum). I bought $30 worth of stuff for only $6 by weight.

12

Getting a bit more done - long weekend, should be able to put a good dent in it…. :beer:

13

Diesel is good for plenty of low end torque… so a floody emitter fits the bill nicely. Subscribed …despite the Patrol part number.

14

Sorry - no Toyota’s at work that day….

…bump for today’s work… :beer:

15

Hey, you got the same sub $5 multi meter I got!

16

Ahhh, but does it have the modded probe wires & repaired trace on the circuit board from trying to measure a little more amps than it can handle? :bigsmile:

17

Looking good. A small spacer that fits in the gap on the lens retainer will prevent it being distorted where the screw goes through. It could also be the start of a mount for a handle or it could just be left the way it is and I'll shut up.

18

I’ll be doing something with the joint on the bezel, I just don’t know what yet… I’ve filed it up a little since that shot to even both the tabs up.

19

going to be a cool shoulder-fired light when its completed :slight_smile:

20

Looking good.