100W LED Flashlight

I was wasting time on Youtube when I came across a video where someone had made a flaslight with a 100W LED.  I was curious how much they were and went to eBay to check.  It turns out they’re pretty cheap at around $8 shipped.  So, of course, I had to make one.  I can’t claim credit for anything new as I’m using similar parts to the folks on Youtube but it was fun to make.

The 100W LED is rated for 3 Amps at 30-35V.  It also puts off a bunch of heat which requires a heat sink.  I could make something but there are ready made heatsinks with fans for this LED on ebay already.  You also need a reflector and lens to focus the light beam.  In the pic below you can see the 100W LED mounted to the heat sink with the lens sitting off to the left.  For reference, I’ve also put in the smaller 10W LED I used on the Wheel Horse.

LEDs require a specific current which means I’ll need a way to supply it.  I also decided I’d use a power tool battery and boost the voltage up to the 30-35 volts needed.  I went back to eBay and found a DC to DC boost converter with adjustable voltage and current capability.  You can see the boost converter in the picture below.  The two blue potentiometers are used to adjust the voltage and current.

Before I built anything I rigged up the fancy testing apparatus shown below.  I picked up a cheap 18V rechargeable lithium drill battery from Harbor Freight to use as my power source.  It’s only 1.3Ah but it came with its own charger.  Importantly, it was also the cheapest option I could find.  To set up the converter, I first adjusted the output voltage to 30V before hooking up the LED.  Then I turned the current potentiometer down and hooked the LED up with my multimeter inline to measure the current.  Turning the LED away from myself, I turned it on and adjusted the current and voltage to give 100W.   Then I took it outside and lit up the world.The LED was bright but I wanted to get a tighter beam out of it.  So, with the current turned down, I messed with the positioning of the lens.  I was never able to get to really narrow the beam though.  I eventually sat down on the computer and did some lens ray tracing to see if I could figure out how to get the beam tighter.  Eventually, I realized that with this size lens and emitter there’s really no way to get a tighter beam.

While I was fiddling with the lens I started using my welding helmet to avoid seeing squares because it’s bright even when dimmed.  I snagged a picture of it at full power through the welding glass for you to see.

After I was done prototyping, I sketched out a few design ideas.  I ended up deciding on a triangular aluminum frame.  The first step was to mount the emitter/heatsink/fan.  I drilled and tapped some holes in the heat sink, turned some standoffs, and mounted it to the bottom rails.

Next, I closed off the end and put the battery in place temporarily.  I came up with a cross piece which links the two sides, attach the handle, and hold the panel.  I also decided I wanted to be able to adjust the brightness of the flashlight while using it.  To do that, I removed the current potentiometer and wired in a bigger potentiometer with a knob that I could easily adjust.  The potentiometer allows me to vary the LED current from 0.4 to 3 amps.  With the structure temporarily assembled, I wired it up again for some more testing.  The resistor sticking up, it just there temporarily to drop the voltage for the 12V fan while I was waiting on a voltage regulator to arrive.  Also, this battery pack doesn’t have a low voltage cutoff, so I’ve added a small display to keep track of the pack voltage.

Once I was happy with it, I disassembled the frame, smoothed the edges, and reassembled it with “proper” wiring.  I also found I needed a glare shield to keep from shining light at myself when using it.  Here’s another view.  I’ve packed the voltage regulator for the fan in between the battery and end of the frame and the voltage gauge onto the battery pack.  Here’s the business end.And the display.Here’s a couple pictures of the flashlight in action.  The camera settings are the same in both images.  On the left is the flash light at the low mode.  On the right is high.  High is pretty bright.

Clearly, I’m not going to get great run time with the flashlight on high.  In fact, I only got about 10 minutes until the voltage meter hit 15V and I shut it down.  At low though, I expect to get over an hour though I haven’t tested it.  Either way its great for when you need to light up an entire yard or signal a UFO!

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Headlights for the Wheel Horse

I went ahead and added LED headlights to my Wheel Horse garden tractor.  The incandescent bubs that were in it would have drawn more amps that the engine’s electrical system produces.  This would result in the battery being drained by the head lights.  To fix this I replaced them with some 10W LED’s I picked up off of ebay.  Together they’ll both draw a little under 2 amps form the electrical system which will leave some to charge the battery.  I’m sure the LED’s are much brighter than the OEM bulbs too.

Below is a pic of the area where the headlights sat.  Previously, there were two circular bulbs that were held in with a tab and bolt.

I used a scrap piece of 1/8″ thick aluminum to hold my LED emitters.  The aluminum will also serve as a heat sink to keep the LEDs from burning up.  I drilled and tapped holes in the plate to hold the emitters and brackets for the lens and reflector.This is a picture of the reflector that goes between the lens and emitter.  It’s made of plastic which is an insulator.  It is important to note that the reflective coating on it does conduct electricity though.  It’s not a dead short like metal would be but I did measure about 11 ohms between one side and the other.

On some other LEDs I’ve got from Ebay the reflectors fit on the white plastic part of the emitter.  On the 10W LEDs the reflector contacts the tabs for the wires that power it.  To insulate the reflector from the wires I used a bit of electrical tape.

Unlike the incandescent lamps, I can’t just hook 12V up to these LEDs even though they’re rated for 12V.  LED’s need a constant current and these require 1 A apiece.  To provide that, I found a simple constant current circuit online.  This circuit only requires two transistors and two resistors.  One of the resistors is used to set the current of the LED.  I assembled the circuit and blobbed some silicone on it.  It’s hackish and I’m sure I’ll be reassembling it at some point.

I temporarily wired everything up and turned the lights on.  They’re pretty darn bright. To give me the option of dimming them some I added an additional switch to the dash which picks between two different valued resistors in the circuit.  The up position on the switch runs the lights a 100% and the down position runs them at 25% current.    They’re still bright in the lower setting but there’s a definite increase switching to “high beams”.   The original light switch still turns them on and off.

Here’s a picture of the new headlights in position.

Finally, here’s a shot at full brightness in the dark.  It lights up with width of my yard, across the street, and a little into the neighbors yard.

So, yay mobile flashlight!

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Small Trailer Resto

I picked up a small trailer to go with the Wheel Horse last year off of Craigslist for cheap.  After I picked it up, I built a tailgate for it but have used it as is since then. It’s seen better day and I finally got around to fixing it back up.  I’m not sure who originally made the trailer but its got 17 cu ft of volume.

As you can see, it’s got some rust and flaking paint on it. OK, mostly rust.

The trailer must have sat front down for a while and collected wet leaves. This caused the heavy rusting in that area.This view is from the inside and backlit to show the rust holes in the bed.  This is a tipper trailer and the front support for the bed is in this area.  Eventually, it would push through the weakened area. After disassembly, I worked on removing all the old paint and rust.  This was easily the worst part of the resto.  I hate removing paint. Once it was mostly clean, I cut out the rusted area to weld some replacement pieces in.Welding in the replacement panels was tougher than I thought it’d be.  Though I’d removed the area where the rust had eaten completely through, there were still a lot of spots where it had partially eaten the metal.   This resulted in the welder burning though in spots and generally being a pain.  Eventually, I got the replacement pieces welded in.The next step was to start painting it.  First, I laid down a coat of primer.

Next, came the paint.  I figured IH red and black would match the Wheel Horse. I also painted the wheels and put new tires on.  I’m getting faster and changing these annoying small tires.

Yay! Finally done with it.

Here it is in use picking up pine straw. 

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Replacement Prentiss Vise Nut

Recently, a reader commented that he had a Prentiss vise with a broken vise nut.  He asked if I knew of how to find a replacement.  I said recommended a few places but said he’d probably have to have one made.  He replied that he had approached several machine shops but none would accept the job.  This isn’t too surprising given what’s involved in making a replacement.  You would either need to single point cut the thread or buy a tap to make the internal threads.  I decided to offer to make the nut for him and he accepted.

He sent me a picture of his broken vise nut. After a few emails back and forth I realized that my Prentiss vise has the same nut which would make reproducing it much easier.   The original nut is made out of cast iron but the new one will be made out of steel.   Cast iron has better wear properties but the vise won’t be seeing a lot of use so it doesn’t matter in this case.

Here’s a picture of my vise nut to show what I’m trying to make. 

The first step in copying the nut was to determine what thread the vise uses.  After some measurements and research I determined that it’s a truncated 7/8″ diameter 3-1/2 TPI 10 deg modified square thread.   This isn’t something you’re going to be able to find a tap for off the shelf.  You’d have to have one custom made as I’m sure the factory did.

I determined that the easiest approach would be to single point cut the thread.  This required grinding an appropriate tool bit.  Though I could use my vise lead screw to test the fit on the nut, its length would require moving the carriage to the end of the lathe each time.  Instead, I decided to make a shorter plug that also let me test cutting the thread.  As I cut the thread on the plug I tested the fit with my vise nut until I got the fit desired.

Here’s a short video showing part of a pass.

Yay, it fits!

I also tested cutting the internal thread into a piece of aluminum.  Using aluminum meant that the machining would take less time than steel.  I learned a great deal cutting the test piece.  Cutting the internal thread took longer than the thread on the plug because the boring bar I used tended to chatter and flex.  I eventually got it done though.  Now on to the steel.

The first step in making the steel nut was to remove some of the material on the front side.  I could have done it after cutting the thread but having less thread to cut was a big positive.

I started by drilling a hole and boring it to the correct size. 

Cutting this thread was slow for several reasons.  This first is due to my lathe.  The carriage doesn’t immediately stop when the feed is disengaged due to momentum in the gear train.  This requires me to run the RPM slowly (about 90 rpm) so I don’t crash the lathe.   The second is due to tool pressure and boring bar flex which required very light passes of about 0.002″ in steel.  This internal thread has a height of about 0.1″.  That’s a lot of slow passes.

I started cutting the thread but ran into an issue where I couldn’t cut the thread any deeper due to the bar flexing.  Since the thread is almost square, a large side force is generated on the boring bar while cutting which causes it to bend.  At a certain depth I could not longer advance the bit into the work.  To deal with this, I made another tool bit that cut a thread with more of a V shape.  This thread shape created less force on the boring bar allowing me to cut the thread to depth.

Next, I went back to my original tool bit and cut the entire thread again.  Since some of the metal had already been removed there was now less force on the boring bar and I was able to get the thread finished.  Once I was near the final depth, I used my test plug to get my desired loose fit.  I didn’t want to make the fit tight because the plug is based off my vise’s lead screw which may have some wear.

Here’s a view showing the internal thread.

Eventually, I moved the carriage to the end of the lathe and tried the actual lead screw.

Once done on the lathe, it was time to remove the extra material from the nut. (That’s a cool smoke trail from a chip!)

Then some grinding and flap disc work.

Finally, I could test fit the nut in my vise and verify it worked.

After this, I got the the nut into the mail and crossed my fingers that it would fit the commenter’s vise.  I know it should but I was still concerned.  Happily, it did fit!  I’m happy to have helped someone out but can firmly say I have no desire to make another one of these.

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Wheel Horse 417-8 Part 5: PTO, Intake, and Exhaust

It’s time for the final Wheel Horse post!  Well, for a little bit at least.

This garden tractor has a clutched multi-step pulley that is engaged/disengaged with a lever.  The lever pulls on a triangular piece that presses the pulley into the clutch disk via the curved piece.  Here’s a image of the original PTO setup.

The top of the PTO setup uses a bracket which bolted up to some holes in the engine.  As expected, the bracket and the holes on the new engine didn’t match up.  I did some testing and determined that I could modify the old bracket by extending the bottom of it, welding up the holes, drilling new holes, and adding a spacer block.  Here’s the bracket in place after all the modifications to it.

With the bracket finished, I was able to put the rest of the mechanism back together.  After a little adjusting of the lever and way to much adjusting of the brake pad, it works as expected. PTO done.Next, I turned my attention to the intake and exhaust.  The intake required modifying because the plastic shroud contacts the hood and doesn’t allow it to close.The muffler, on the other hand, fits perfectly under the hood when closed.The exit on the exhaust was aligned with one of the headlight holes and would probably work fine this way for a while.  I removed the stock muffler and was able to snake a cable in for the throttle lever.  From HF, the engine has two different places that a throttle cable can be mounted.  There’s also multiple unused bolt holes in the engine.  I used one to hold a clip for the cable. With the intake shroud removed I was able to start thinking about how to make my own intake.  I looked around online and saw that several companies make an adapter piece that allows a round clamp on air filter to be used.

I took some measurements and found a piece of aluminum to make my intake adapter out of.  I started by boring the inside out on my Hendey lathe.

After some more work I took it over to the mill to make the small slots and drill the holes for the studs.  I broke a small drill bit off in one of the holes and had to bore it out with a 3/8″ carbide mill which left it a little oversized.

Now I can mount the adapter to the carb.  I’ve also attached the choke cable to my adapter.  The choke lever moves backwards to the direction I’d prefer which requires running the cable out and then back to the lever.  Next, I drilled a small hole in the lever and put the end of the cable into it.   I also slightly modified the hood to clear the adapter.I ordered a oiled foam filter to use for the intake.  I don’t expect to use my tractor in dusty conditions because we only have sand down here.  Even though the stock muffler fit under the hood, I wanted a different exhaust.  I tried several different things before ending up with this exhaust which works pretty well.  With the muffler removed you can see the exhaust port.The first step was to make an exhaust flange that bolts to the engine’s head.  To do that, it’s back to the Hendey to bore the hole to fit the exhaust adapter.Next, it’s over to the mill to shape it a little more and drill the holes for the studs.  I could have bored the big hole on the mill but it was easier for me on the lathe.  After this pic, I ground the sharp points off on the grinder.Now I can assemble the rest of the exhaust.  After searching for a while I found this muffler meant for a Ford 2N,8N, or 9N.  It seems kinda small for a full size tractor but it was a good size for me. I also bought a 90 deg bend (because I failed at trying to bend my own) and a rain cap as cheap insurance against ruining the engine.  I’ve also attached a bracket on the bottom of the bend to provide additional support for the muffler. 

I found out the hard way that the grey paint on the muffler was in no way heat rated.  After painting it twice with high temp paint, I finally had an exhaust I was happy with.

Finally, I’m done…for the most part.  I will probably add some headlights back in and give it a coat of paint in the future.  But for now I’m happy with it and am able to use it.  Here are a few pictures of the Wheel Horse 417-8 with Predator 420 engine swap.  I also added a little shroud over the intake filter.  It’ll block rain falling straight down but that’s about it.

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Wheel Horse 417-8 Part 4: Electrical

This is going to be a wordy post on the electrical joining of the motor and chassis because there’s only so many pictures of wires I can show you.  I wanted to join the electrical system of the new motor with the safety switches and dashboard of the tractor.  The motor needs its electrical system to run and has a low oil switch to shut the motor off if the oil level drops below a certain level.  The tractor has switches on the the seat, PTO, and clutch pedal which control how it can start and run and a voltmeter and hour meter on the dash which I’d like to keep.  Additionally, the tractor also has lights which I plan to change over to LEDs at some point in the future.

The Predator and Kohler motors use different approaches when it comes to ignition.  The Kohler I removed uses the battery to charge a capacitor which discharges through a coil to generate the spark.  Turning the key off cuts the 12V power, stopping the spark, and shuting off the motor.  The Predator has a magneto that generates an electrical pulse that goes to the coil automatically when the flywheel turns.  To shut this engine off, the coil is grounded stopping the spark.

After thinking about it for a while, I finally came up with a way of joining the electrical systems which gave me most of what I wanted.  Originally, the tractor would not start with the PTO engaged but I wasn’t able to replicate that function.  It also wouldn’t continue to run if you got off the seat with the PTO engaged which could be good or bad.

Below is an electrical diagram of a Honda GX390 which the Predator is a clone of.  The blue boxes show the areas where I added circuitry for the voltmeter and hour meter.  The red box shows the safety switches.

To power the gauges I needed 12V DC when then the motor is running only.  I could get this power by connecting the gauges to the battery with a switch but I didn’t want to have to remember to throw the switch each time.  Instead, I decided to use a relay that is powered off the motor’s charging coil.  When the motor is generating electricity, the relay closes allowing the volt meter and hour meter to receive power.  I also needed to filter this power to make the gauges work correctly.  More on this below.

When the key is in the start position battery power is sent to the starter solenoid via the ignition switch (called engine switch in the diagram).  I put my safety switches in this path.  The result is that the clutch pedal must be depressed and either the seat switch closed or PTO off.  This does allow the engine to start with the PTO on but I wasn’t able to figure out a way to avoid this.  Instead, I’ll just pay attention.

Here’s a picture of the ignition switch and circuit breaker in the original box that came with the motor.  Though unseen, it also holds the engine’s original rectifier.  I removed all of this for reuse.Fitting the ignition switch in the dash required enlarging the old switche’s hole.After that I was able to able to fit the ignition switch, voltmeter, and new hour meter into the dash panel.  The large piece of heat shrink tubing contains the filtering capacitors for the gauges.  Here it is all in place.  Looks like it was made that way.  I put the light switch back in and ran the wiring for the future lights. The original headlights are incandescents and with some quick math I was able to determine their current draw.  The old motor’s charging coil was sized to run the lights and charge the battery at the same time.  My new motor doesn’t put out as much current and running the original lights would drain the battery  with the tractor running.  To reduce the current draw and provide better lighting I plan to find some LED lights.I picked up a small electrical box to house all the electrical bits and mounted it between the motor and firewall.  In the top right of the picture you can see the old starter solenoid which was later removed.  I have a lid for the box which should keep things dry.I mentioned needing to filter the power going to the gauges.  The following picture shows why.  On the left is the power before filtering.  As you can see, the voltage switches between 13V and 0 volts because due to the rectification.  I put a capacitor across the wires going to the gauges to give me constant voltage as shown in the right side of the picture.  The capacitor acts like a small power tank which fills when the voltage is high and releases power when the voltage is low.  In this was, constant voltage is supplied.

With the electrical taken care of I can now turn my attention to getting the throttle and choke hooked up, and fitting the hood back on.  That’ll be in the next post.


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Wheel Horse 417-8 Part 3: Starting Motor Replacement

After looking into the cost to rebuild the motor on my Wheel Horse 417-8, I decided to start looking for a new motor to replace the old one.  I settled on a Predator 420 single cylinder engine from Harbor Freight.  Predator is Harbor Freight’s home brand name for small engines, but it’s simply another Honda clone made in China.  The motors have a reputation for being reliable and cheap which fits both my requirements.  This is the hemi version of this motor and is rated at 13 hp and about 20 ft*lb tq.  Other bands rate this motor at 15 hp.  So, mine may have a little more power than stated.  The motor also comes with keyed electric start which I also wanted.  One small issue is the PRO shaft on the new motor is 1″ diameter while the old motor’s is 1-1/8″

To locate the new motor, I have to make sure that the PTO shaft is in the same position as the old one.  The pulley that powers the tractor as well as the front PTO clutch sit on the shaft.  To find where the PTO shaft needs to go I first had to put the old motor back in and measure the PTO shaft’s location in all three dimensions.  I ended up clamping a carpenter’s square onto the frame and, using another square, measured the location from the front corner of the frame.


Next, I removed the old motor again and put the new one in place.  Here’s a pic of the new motor fresh from the box. It’s bigger than the old one but I plan to working to make it fit under the hood.


To locate the new motor. I moved it around until the PTO shaft was in the right location along the length of the tractor.  I also measured the height to the PTO shaft and found that it was 1″ lower than needed.  Finally, I put the drive pulley and clutch disk loosely onto the shaft and nudged the motor into position out from the middle of the tractor.  The old motor sat on a 1/4″ thick plate that I planned to reuse meaning I need to make some 3/4″ spacers to raise the engine.


To address the difference in PTO shaft size, I decided to make as spacer out of some 1-1/4″ bar stock.  First I drilled out the center and bored it to size.


Here’s a pic of me testing the fit of the spacer on the shaft and inside the PTO clutch disk.


Once I knew it fit, I used to the mill to cut the keyway slot.  Only the drive pulley is keyed so I didn’t need to mill along the entire length of the spacer.  Then it was back to the lathe to trim off the excess.


The spacer also required a 1/16″ taller key.  I machined one out of some 3/8″ key stock and fit it to the PTO shaft.  Below is a pic showing the test fit with the spacer on backwards before trimming down the key.


Making the spacers was simple enough on the lathe.  I used some 1″ aluminum bar that I drilled out to a little over 3/8″ and parted off quickly.


I bolted the plate down with the new spacers and re-positioned the motor as before.  I then used some paint on the end of a short bolt to mark spots to drill holes for the bolts that will hold the motor to the plate.


After that, I put the drive pulley and belt back on and was able to take a test drive by pull starting the motor.  I drove around some and the motor performed as expected.   It seems about the same as the old motor except for the exhaust note.


Here’s a view of the other side showing the drive belt.  Obviously, a few panels were off for my test drive.


Well, now that it runs again I think we can call it done!  Nah, of course I’m not done yet.  Next, I’ll be merging the electrical system of the tractor and new motor together.  I want to have all the dash controls on the tractor working again and the hood back on as well.

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