Tool Hacks

2884 Articles

Casting Metal With A Microwave And Vacuum Cleaner

September 29, 2022 by 38 Comments

Metalworking might conjure images of large furnaces powered by coal, wood, or electricity, with molten metal sloshing around and visible in its crucible. But metalworking from home doesn’t need to use anything more fancy than a microwave, at least according to [Denny] a.k.a. [Shake the Future]. He has a number of metalworking tools designed to melt metal using a microwave, and in this video he uses them to make a usable aluminum pencil with a graphite core.

Before getting to the microwave kiln, the pencil mold needs to be prepared. A 3D-printed pencil is first created with the graphite core, and then [Denny] uses a plaster of Paris mixture to create the mold for the pencil. The 3D printed plastic is left inside the mold and placed in the first microwave kiln, which is turned on just enough to melt the plastic out of the mold, leaving behind the graphite core. From there a second kiln goes into the microwave to melt the aluminum.

Once the molten aluminum is ready, it is removed from the kiln and poured in the still-warm pencil mold. This is where [Denny] has another trick up his sleeve. He’s using a household vacuum cleaner to suck the metal into place before it cools, creating a rudimentary but effective vacuum forming machine. The result is a working pencil, at least after he wears down a few razor blades attempting to sharpen the metal pencil. For more information about how [Denny] makes these microwave kilns, take a look at some of his earlier projects.

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Measuring Impedance Virtually

September 26, 2022 by 9 Comments

We always enjoy a [FesZ] video and we wonder if the “Z” stands for impedance? That’s the topic of his latest video series: measuring impedance with LTSpice. Of course, he also does his usual thorough job of mapping the virtual world to the real one. You can see the video below.

It is simple enough. Impedance is very similar to resistance. That is to say, we have a ratio of voltage and current. However, since it is an AC quantity, you need a complex number to represent it and there is an associated phase shift.

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On the left, an image of a COB on the multimeter's PCB. On the right, a QFP IC soldered to the spot where a COB used to be, with pieces of magnet wire making connections from the QFP's pins to the PCB tracks.

Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP

September 25, 2022 by 16 Comments

The black blobs on cheap PCBs haunt those of us with a habit of taking things apart when they fail. There’s no part number to look up, no pinout to probe, and if magic smoke is released from the epoxy-buried silicon, the entire PCB is toast. That’s why it matters that [Throbscottle] shared his journey of repairing a vintage multimeter whose epoxy-covered single-chip-multimeter ICL7106 heart developed an internal reference fault. When a multimeter’s internal voltage reference goes, the meter naturally becomes useless. Cheaper multimeters, we bin, but this one arguably was worth reviving.

[Throbscottle] doesn’t just show what he accomplished, he also demonstrates exactly how he went through the process, in a way that we can learn to repeat it if ever needed. Instructions on removing the epoxy coating, isolating IC pins from shorting to newly uncovered tracks, matching pinouts between the COB (Chip On Board, the epoxy-covered silicon) and the QFP packages, carefully attaching wires to the board from the QFP’s legs, then checking the connections – he went out of his way to make the trick of this repair accessible to us. The Instructables UI doesn’t make it obvious, but there’s a large number of high-quality pictures for each step, too.

The multimeter measures once again and is back in [Throbscottle]’s arsenal. He’s got a prolific history of sharing his methods with hackers – as far back as 2011, we’ve covered his guide on reverse-engineering PCBs, a skillset that no doubt made this repair possible. This hack, in turn proves to us that, even when facing the void of an epoxy blob, we have a shot at repairing the thing. If you wonder why these black blobs plague all the cheap devices, here’s an intro.

We thank [electronoob] for sharing this with us!

Better Scope Measurements

September 22, 2022 by 6 Comments

There was a time when few hobbyists had an oscilloscope and the ones you did see were old military or industrial surplus that were past their prime. Today you can buy a fancy scope for about what those used scopes cost that would have once been the envy of every giant research lab. However, this new breed of instrument is typically digital and while they look like an old analog scope, the way they work leads to some odd gotchas that [Arthur Pini] covers in a recent post.

Some of his tips are common sense, but easy to forget about. For example, if you stack your four input channels so each uses up a quarter of the screen, it makes sense, right? But [Arthur] points out that you are dropping two bits of dynamic range, which can really jack up a sensitive measurement.

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Metric And Inch Threads Fight It Out For Ultra-Precise Positioning

September 21, 2022 by 20 Comments

When you’re a machinist, your stock in trade is precision, with measurements in the thousandths of your preferred unit being common. But when you’re a diemaker, your precision game needs to be even finer, and being able to position tools and material with seemingly impossibly granularity becomes really important.

For [Adam Demuth], aka “Adam the Machinist” on YouTube, the need for ultra-fine resolution machinist’s jacks that wouldn’t break the bank led to a design using off-the-shelf hardware and some 3D printed parts. The design centers around an inch-metric thread adapter that you can pick up from McMaster-Carr. The female thread on the adapter is an M8-1.25, while the male side is a 5/8″-16 thread. The pitches of these threads are very close to each other — only 0.0063″, or 161 microns. To take advantage of this, [Adam] printed a cage with compliant mechanism springs; the cage holds the threaded parts together and provide axial preload to remove backlash, and allows mounting of precision steel balls at each end to make sure the force of the jack is transmitted through a single point at each end. Each full turn of the jack moves the ends by the pitch difference, leading to ultra-fine resolution positioning. Need even more precision? Try an M5 to 10-32 adapter for about 6 microns per revolution!

While we’ve seen different thread pitches used for fine positioning before, [Adam]’s approach needs to machining. And as useful as these jacks are on their own, [Adam] stepped things up by using three of them to make a kinematic base, which is finely adjustable in three axes. It’s not quite a nanopositioning Stewart platform, but you could see how adding three more jacks and some actuators could make that happen.

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3D Printing Aids Metal Polishing

September 20, 2022 by 9 Comments

While a machinist can put a beautiful finish on a piece of metal with their lathe or mill, to achieve the ultimate finish, a further set of polishing procedures are necessary. Successively finer abrasives are used in a process called lapping, which removes as far as possible any imperfections and leaves eventually a mirrored smoothness. It’s not without problems though, particularly at the edge of a piece it can result in rounded-off corners as the abrasive rubs over them. [Adam the machinist] has a solution, and he’s found it with a 3D printer.

To avoid the rounded edges, the solution involves fitting a piece of metal or wood flush with the surface to be lapped, such that the pressure doesn’t act upon the corner. This can be inconvenient, and the solution avoids it by 3D printing a custom piece that fits over the entire machined object providing a flat surface surrounding the edges. We see it being used with a demonstration piece that has three separate surfaces in the same plane to lap,something that would have been challenging without the 3D printed aid.

Lapping isn’t a process we see too often here. But it has cropped up as an extreme overclocking technique.

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A Vacuum Pick Up Tool For Not A Lot

September 18, 2022 by 13 Comments

When working with grain-of-dust surface-mount components, one of the tools which makes a huge difference is a vacuum pickup pen. Instead of trying to move the part with tweezers and succeeding only in flicking it into the middle distance, a tiny rubber suction cup with a vacuum feed allows you to pick it up and place it exactly where it is required. Unfortunately, good vacuum pickup tools come at a price, and very cheap ones aren’t worth the expenditure.

This is where [TDG (Béla)]’s SMD vacuum pickup tool comes in. The problem with the cheap tools is only that their manual vacuum is ineffectual, they come with the required array of probes with the suction cups. The solution is to take a small vacuum pump with a low voltage motor and attach it with a 3D printed adapter to the business end of a cheap vacuum tool and make a useful tool the result.

There’s a short video of the tool in action that we’ve placed below the break. It’s a bit noisy, but it’s obvious that it performs well. Control is via an air hole in the side of the 3D print, place a finger over it and the full suction is directed to the tip. The result is simpler and cheaper than previous contenders in the budget vacuum pickup stakes.

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