Bulking Up A Lightweight Lathe With A Concrete Cart

March 5, 2017 by Dan Maloney 21 Comments

When it comes to machine tools, a good rule of thumb is that heavier is better. A big South Bend lathe or Bridgeport mill might tip the scales at ludicrous weight, but all that mass goes to damping vibration and improving performance. So you’d figure a lathe made of soda cans could use all the help it could get; this cast concrete machine cart ought to fit the bill nicely

Perhaps you’ve caught our recent coverage of [Makercise]’s long and detailed vlog of his Gingery lathe build. If not, you might want to watch the 5-minute condensed video of the build, which shows the entire process from melting down scrap aluminum for castings to first chips. We love the build and the videos, but the lightweight lathe on that wooden bench never really worked for us, or for [Makercise], who notes that he was never able to crank the lathe up to full speed because of the vibrations. The cart attempts to fix that problem the old fashioned way – more mass.

There are a few “measure twice, cut once” moments in the video below, as well as a high pucker-factor slab lift that could have turned into a real disaster. We might have opted for a countertop-grade concrete mix that could be dyed and polished, but that would be just for looks. When all is said and done, the cart does exactly what it was built to do, and there’s even room on it for the shaper that’s next on the build list. We’re looking forward to that.

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Beefy 100 Amp Electronic Load Uses Two MOSFETs

February 28, 2017 by Al Williams 31 Comments

[Kerry Wong] had some extreme MOSFETs (IXTK90N25L2) and decided to create a high current electronic load. The result was a two-channel beast that can handle 50 A per channel. Together, they can sink 400 W and can handle a peak of 1 kW for brief periods. You can see a demo in the video below.

An electronic load is essentially a load resistor you can connect to a source and the resistance is set by an input voltage. So if the load is set to 10 A and you connect it to a 12 V source, the MOSFET should look like a 1.2 ohm resistor. Keep in mind that’s 120 watts–more power than a common incandescent light bulb. So you are going to need to carry some heat away.

The circuit is pretty simple. The FETs accept a voltage on their gates that sets them to look effectively like a resistor that varies with the voltage. A very small source resistor develops a voltage based on current (only 75 mV for a 50 A draw). That voltage feeds a comparator which generates the gate voltage after looking at the input control voltage. Each millivolt into the comparator translates to an additional 1.33 A through the load.

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Ask Hackaday: What’s Your Etchant?

February 28, 2017 by Al Williams 88 Comments

Although the typical cliché for a mad scientist usually involves Bunsen burners, beakers, and retorts, most of us (with some exceptions, of course) aren’t really chemists. However, there are some electronic endeavors that require a bit of knowledge about chemistry or related fields like metallurgy. No place is this more apparent than producing your own PCBs. Unless you use a mill, you are probably using a chemical bath of some sort to strip copper from your boards.

The standard go-to solution is ferric chloride. It isn’t too tricky to use, but it does work better hot and with aeration, although neither are absolutely necessary. However, it does tend to stain just about everything it touches. In liquid form, it is more expensive to ship, although you can get it in dry form. Another common etchant is ammonium or sodium persulphate.

There’s also a variety of homemade etchants using things like muriatic acid and vinegar. Most of these use peroxide as an oxidizer. There’s lots of information about things like this on the Internet. However, like everything on the Internet, you can find good information and bad information.

When [w_k_fay] ran out of PCB etchant, he decided to make his own to replace it and wrote a great guide on how this is done. He found a lot of vague and conflicting information on the Internet. He read that the vinegar solution was too slow and the cupric acid needs a heated tank, a way to oxygenate the solution, and strict pH controls. However, he did have successful experiments with the hydrochloric acid and peroxide. He also used the same materials (along with some others) to make ferric chloride successfully.

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DIY Syringe Pump Saves Big Bucks For Hacker’s Lab

February 26, 2017 by Dan Maloney 55 Comments

If you had a choice between going to your boss and asking for funds for a new piece of gear, would you rather ask for $3000 to buy off-the-shelf, or $200 for the parts to build the same thing yourself? Any self-respecting hacker knows the answer, and when presented with an opportunity to equip his lab with a new DIY syringe pump for $200, [Dr. D-Flo] rose to the challenge.

The first stop for [Dr. D-Flo] was, naturally, Hackaday.io, which is where he found [Naroom]’s syringe pump project. It was a good match for his budget and his specs, but he needed to modify some of the 3D printed parts a little to fit the larger syringes he intended to use. The base is aluminum extrusion, the drive train is a stepper motor spinning threaded rod and a captive nut in the plunger holders, and an Arduino and motor shield control everything. The drive train will obviously suffer from a fair amount of backlash, but this pump isn’t meant for precise dispensing so it shouldn’t matter. We’d worry a little more about the robustness of the printed parts over time and their compatibility with common lab solvents, but overall this was a great build that [Dr. D-Flo] intends to use in a 3D food printer. We look forward to seeing that one.

It’s getting so that that you can build almost anything for the lab these days, from peristaltic pumps to centrifuges. It has to be hard to concentrate on your science when there’s so much gear to make.

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Old Thermometer Gets New Eyes

February 24, 2017 by Bryan Cockfield 14 Comments

As much as we’d like to have the right tools for the right job all of the time, sometimes our parts drawers have other things in mind. After all, what’s better than buying a new tool than building one yourself from things you had lying around? That’s at least what [Saulius] must have been thinking when he needed a thermometer with a digital output, but only had a dumb, but feature-rich, thermometer on hand.

Luckily, [Saulius] had a webcam lying around as well as an old thermometer, and since the thermometer had a LCD display it was relatively straightforward to get the camera to recognize the digits in the thermometer’s display. This isn’t any old thermometer, either. It’s a four-channel thermometer with good resolution and a number of other useful features (with an obvious lack of communications abilities), so it’s not something that he could just overlook.

Once the camera was mounted to an arm and pointed at the thermometer’s screen, an algorithm running on a computer detects polygons and reports its information into a CSV file. This process is made simpler by the fact that LCD screens like this are very predictable. From there, the data is imported into LibreOffice and various charts and graphs can be made.

Although perhaps not the most elegant of hacks, sometimes you have to work with the supplies that are on hand at the time. Sometimes the tools you need are too expensive, politically dangerous, or too impractical to obtain. To that end [Saulius]’s hack is a great example of what hacks are possible with the right mindset.

60 Watt USB Soldering Iron Does It With Type-C

February 24, 2017 by Anool Mahidharia 40 Comments

Some time back we ran a post on those cheap USB soldering irons which appeared to be surprisingly capable considering they were really under powered, literally. But USB Type-C is slated to change that. Although it has been around for a while, we are only now beginning to see USB-C capable devices and chargers gain traction. USB-C chargers featuring the USB-PD option (for power delivery) can act as high power sources allowing fast charging of laptops, phones and other devices capable of negotiating the higher currents and voltages it is capable of sourcing. [Julien Goodwin] shows us how he built a USB-C powered soldering iron that doesn’t suck.

He is able to drive a regular Hakko iron at 20 V and 3 Amps, providing it with 60 W of input power from a USB-C charger. The Hakko is rated for 24 V operating voltage, so it is running about 16% lower ~~power~~ voltage. But even so, 60 W is plenty for most cases. The USB-C specification allows up to 5 A of current output in special cases, so there’s almost 100 W available when using this capability.

It all started while he was trying to consolidate his power brick collection for his various computers in order to reduce the many types and configurations of plugs. Looking around, he stumbled on the USB-PD protocol. After doing his homework, he decided to build a USB Type-C charger board with the PD feature based on the TI TPS65986 chip – a very capable USB Type-C and USB PD Controller and Power Switch. The TI chip is a BGA package, so he had to outsource board assembly, and with day job work constantly getting in the way, it took a fair bit of time before he could finally test it. Luckily, none of the magic smoke escaped from the board and it worked flawlessly the first time around. Here is his deck of slides about USB-C & USB-PD [PDF] that he presented at linux.conf.au 2017 Open Hardware Miniconf early this year. It provides a nice insight to this standard, including a look at the schematic for his driver board.

Being such a versatile system, we are likely to see USB-C being used in more devices in the future. Which means we ought to see high power USB Soldering Irons appearing soon. But at the moment, there is a bit of a “power” struggle between USB-C and Qualcomm’s competing “Quick Charge” (QC) technology. It’s a bit like VHS and Betamax, and this time we are hoping the better technology wins.

Plasma Cutter Jig Notches Tubing Quickly And Cleanly

February 23, 2017 by Dan Maloney 14 Comments

It may be [MakeItExtreme]’s most ambitious build to date. There are a lot of moving parts to this plasma cutter tubing notcher, but it ought to make a fine addition to the shop and open up a lot of fabrication possibilities.

We have to admit to a certain initial bafflement when watching the video below for the first time. We can usually see where [MakeItExtreme]’s builds are going right from the first pieces of stock that get cut, but the large tube with the pressed-in bearing had us scratching our heads. The plan soon became clear — a motorized horizontal rotary table with a hollow quill for the plasma torch leads. There’s a jig for holding the torch itself that can move in and out relative to the table. Cams made of tube sections can be bolted to a fixed platen; a cam follower rides on the cams and moves the torch in and out as the table rotates. This makes the cuts needed to properly fit tubes together — known as fish mouth cuts or saddle cuts. The cams can be removed for straight cuts, and the custom pipe vise can be adjusted to make miter cuts.

All in all a sturdy and versatile build that ought to enable tons of new projects, especially when teamed up with [MakeIt Extreme]’s recent roll bender.

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