Tool Hacks

2859 Articles

These Wire Strippers Are Made From PCBs

April 13, 2019 by 12 Comments

The rise in cheap PCB fabrication has made old-school prototyping methods such as wire wrapping somewhat passé, but it still has its place. And if you’re going to wire wrap, you’re going to want a quick and easy way to strip that fine Kynar-insulated wire. So why not use PCB material to make this handy wire-wrapping wire stripper?

The tool that [danielrp] built is pretty simple – just a pair of razor blades held together so as to form a narrow slot to cut insulation while leaving the conductor untouched. The body of the tool is formed of two PCBs, between which the blades are sandwiched. [danielrp] designed the outline of the PCBs in DraftSight, then exported a DXF into EAGLE to make the Gerbers. The fabricated boards needed a little post-processing, including tapping the holes on one side to accept the screws that hold the tool together. We were surprised that FR4 took the threads at all, but it seems to work for this low-torque application. The disposable snap-type blades were sandwiched between the PCBs and the gap between them adjusted for nick-free stripping. The video below shows the design and build process.

We always appreciate homemade tools, and the fact that you can get a stack of PCBs for almost nothing makes us wonder what else we could use them for. We recently saw them used in a unique word clock, and even turned into a folding circuit sculpture.

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Build Your Own Vacuum Chamber For Degassing And More

April 12, 2019 by 23 Comments

A vacuum chamber can be a useful thing to have around the shop. It can be used for all manner of purposes, from science experiments to degassing paints and epoxies. They’re not something you’d find in every workshop, but never fear – you can always build one from scrap you’ve got lying around! (YouTube video, embedded below.)

[VegOilGuy] begins the build with a simple plywood box, which gets screwed together and then tarted up with bodyfiller and paint. This helps to make the box airtight, as well as improving the aesthetics. A slot is then cut in the lid, and then filled with an excessive amount of silicone sealant. A flat plate covered in aluminium foil is placed on top, and the silicone is left to cure for several days.This is used to create a flat sealing surface for the lid to be placed on later.

Once the seal is complete, it’s a simple plumbing job to finish the chamber. [VegOilGuy] does a great job of demonstrating copper soldering and the proper way to install the necessary taps and check valves. Combined with an electric pump, the vacuum chamber passes its tests with flying colors, completely ruining some marshmallows in the process.

With a few dollars spent online for the special bits, it’s a build that any handy maker could throw together in a weekend. You can always go another route, though – like using an old fridge compressor to get the job done.

[Thanks to Keith O for the tip!]

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This Bike Pump Now Sucks

April 11, 2019 by 18 Comments

Pulling a vacuum is something every proud maker must do once in a while. Whether you’re degassing epoxy or vacuum forming parts, you’ll need a reliable pump to get the job done. [drcrash] has just the guide to help – on how to convert a regular handpump to vacuum duty. (Video embedded after the break.)

[drcrash] recommends starting with a Slime brand 2060-A pump or similar. It’s a basic hand pump, with no pressure gauges or other frills to get in the way. It’s also got a strong steel shaft that can hold up to repeated use. You’ll also need some tubing and a check valve to get the job done.

The basic concept is to reconfigure the pump to suck air out of things rather than blowing it into them. By removing the original check valve and installing one in the opposite direction, and reversing the pump’s piston, it’s possible to pull good vacuum without breaking a sweat. [drcrash] reports that it’s possible to go up to 11 psi below atmospheric with this setup, which is plenty for a wide range of applications. If you need to go further, you can try building your own turbomolecular pump instead.

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Restoring An HP LCZ Meter From The 1980s

April 7, 2019 by 11 Comments

We are fantastically lucky not only in the parts that are easily available to us at reasonable cost, but also for the affordable test equipment that we can have on our benches. It was not always this way though, and [NFM] treats us to an extensive teardown and upgrade of a piece of test equipment from the days when a hacker’s bench would have been well-appointed with just a multimeter and a 10MHz ‘scope.

The Hewlett Packard 4276A LCZ meter is, or perhaps was, the king of component testers. A 19″ rack unit that would comfortably fill a shelf, it has a host of functions and a brace of red LED displays. This particular meter had clearly seen better days, and required a look inside just to clean up connectors and replace aged batteries.

In the case is a backplane board with a series of edge connectors for a PSU, CPU, and analogue boards. Aged capacitors and those batteries were replaced, and those edge connectors cleaned up again. The CPU board appears to have a Z80 at its heart, and we’re sure we spotted a 1987 date code. There are plenty of nice high-quality touches, such as the individual 7-segment digits being socketed.

An after-market option for this equipment included a DC offset board, and incredibly HP publish its full schematic and a picture of its PCB in their manual. It was thus a simple process and quick PCB ordering to knock up a modern replica, with just a few component substitutions and single resistors replacing an HP specific encapsulated resistor pack.

As a treat we get a ringside seat for the set-up and alignment of the machine. The DC offset board gives the wrong voltage, which he traces to a voltage reference with a different tolerance to the original HP part. [NFM] makes some adjustments to resistor values, and is able to pull the voltage to the correct value. Finally we see the instrument put through its paces, and along the way have a demonstration of how capacitance of a ceramic capacitor can vary with voltage close to its working voltage. Even if you never have the need for an LCZ meter or never see an HP 4276A, this should be worth a watch. And if you now have an urge to find a bench full of similar treasures, take a look at our guide to old test equipment.

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Shop-Built Fixtures Reveal The Magic Of Switchable Permanent Magnets

April 7, 2019 by 22 Comments

Have you ever wondered how switchable magnets work? Not electromagnets, but those permanent magnet fixtures like the ones that hold dial indicators to machine tools, or the big, powerful chucks for surface grinders that can be mysteriously demagnetized at the flick of a lever. It seems like magic.

Thanks to [Andrew Klein] and this video on shop-built magnetic switches, the magic is gone. As it turns out, the ability to nullify the powerful magnetic field from a bunch of rare earth permanent magnets is as simple as bringing in another set of magnets to cancel out the magnetic fields of the first set.

[Andrew]’s magnetic pucks are formed from two thick plywood discs with magnets set into the edges. These magnets alternate in polarity around the discs, and they match up with mild steel pole pieces set into the face of the discs. The two discs swivel on a common axis; when the top disc is swiveled so that the polarity of the top and bottom magnets align, the magnet is switched on. Swiveling the top 60° puts the opposing fields in line with each other, canceling out the powerful combined pull of all the magnets and releasing the fixture.

[Andrew] sells a set of plans for the magswitches, which he built using standard woodshop tools. We think the design is perfect for a CNC router, though, where the fussy boring and counterboring operations might be a little easier. Perhaps even a 3D-printed version would be possible. This isn’t the first switchable magnet we’ve seen, of course, but we like this one because it’s all mechanical.

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Hexagons – The Crazy New Breadboard

April 6, 2019 by 11 Comments

A breadboard is a great prototyping tool for verifying the sanity of a circuit design before taking the painstaking effort of soldering it all together permanently. After all, a mistake in this stage can cost a lot of time and possibly material, so it’s important to get it right. [daverowntree] wasn’t fully satisfied with the standard breadboard layout though, with fixed rows and columns. While this might work for most applications, he tried out a new type of prototyping board based on hexagons instead.

The design philosophy here revolves around tessellations, a tiling method for connecting the various components on this unique breadboard rather than using simple rows. The hexagons are tessellated across the board, allowing for some unique combinations that might make it slightly more complicated, but can have some benefits for other types of circuits such as anything involving the use of a three-wire device like a transistor.

The post is definitely worth a read, as [daverowntree] goes through several examples of this method of prototyping where the advantages are shown, like a voltage follower circuit and some other circuits involving transistor biasing. If you’re OK with the general design of breadboards, though, and just wished you didn’t have to do anything after the prototyping stage, we’ve got some help for you there as well.

Building A Vibration Tumbler On The Cheap

April 5, 2019 by 8 Comments

There are few tasks quite as laborious as sanding and polishing. Any job that takes a lot of time and elbow grease is a prime candidate for mechanical help, and this one is no exception. At the suggestion of friends, [VegOilGuy] decided it was time to invest in a vibration tumbler. Naturally, building it rather than buying it was the order of the day.

If you’ve ever used an electric sander, you’ll know they’re an excellent source of vibration. Initially, the intention was to build a tumbler with the sander being removable and still usable for its original purpose. A clamping base was constructed with cable ties, wood, and Bondo, but sadly to no avail. The Velcro connection to the plastic tumbler bowl was simply not robust enough to hold up to repeated use.

Instead, the sander was permanently bolted to the tumbler bowl, yielding more positive results. A funnel was then also added to the bowl, to improve media circulation and reduce the amount required. Initial tests were positive, with the tumbler successfully polishing some cast brass parts using crushed walnut shells. [VegOilGuy] is still looking for a more abrasive media to use for initial patina removal, however.

Sometimes the best tools are the ones you build yourself. In this case, it’s a cheap and easy way to get a vibration tumbler and the results are great. If sanders aren’t your speed, why not check out this fan based build instead? Video after the break.

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