DIY Car Wheel Bearing Puller

March 21, 2015 by Rich Bremer 24 Comments

Cars are the greatest. They get you to where you need to go… most of the time. They can also let you down at the worst moment if a critical part fails. Wheel bearings get a lot of use while we drive and [Dmitriy] found out the hard way how quickly they can fail. Instead of getting cranky about it, he set out to change the damaged bearing himself. In the process he made a pretty neat DIY bearing puller.

Some wheel bearings, on the front of a 2WD truck for example, are only held on by one large nut and easily slide off the spindle. This was not the case for the rear of [Dmitriy’s] AWD Subaru. The rear bearings are press-fit into a bearing housing. These are hard to remove because Outer Diameter of the bearing is actually just slightly larger than the Inner Diameter of the bearing housing. This method of retaining parts together is called an ‘interference fit‘.

[Dmitriy’s] gadget uses one of Hackaday’s favorite simple machines, the screw, to slowly force the bearing out of its housing. It works by inserting a threaded rod through the bearing and bearing housing. Each side has a large washer and nut installed as well as a PVC pipe spacer providing support for the threaded rod. As the opposing nuts are tightened, one washer presses against the bearing and the bearing slowly slides out of the housing. Installation of the new bearing is the same except the tool is reversed to press the bushing into the housing.

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DIY Oscilloscope With A Scanning Laser

March 19, 2015 by Ethan Zonca 20 Comments

If you’ve ever used an old-school analog oscilloscope (an experience everyone should have!) you probably noticed that the trace is simply drawn by a beam that scans across the CRT at a constant rate, creating a straight line when there’s no signal. The input signal simply affects the y-component of the beam, deflecting it into the shape of your waveform. [Steve] wrote in to let us know about his home-built “oscilloscope” that works a lot like a simple analog oscilloscope, albeit with a laser instead of a CRT.

[Steve]’s scope is built out of a hodgepodge of parts including Lego, an Erector set, LittleBits, and a Kano Computer (based on a Raspberry Pi). The Pi generates a PWM signal that controls the speed of a LittleBits motor. The motor is hooked up to a spinning mirror that sweeps the laser across some graph paper, creating a straight laser line.

After he got his sweep working, [Steve] took a small speaker and mounted a mirror to its cone. Next he mounted the speaker so the laser’s beam hits the mirror on the speaker, the spinning sweep mirror, and finally the graph paper display. The scope’s input signal (in this case, audio from a phone) is fed into the speaker which deflects the laser beam up and down as it is swept across the paper, forming a nice oscilloscope-like trace.

While [Steve]’s scope might not be incredibly usable in most cases, it’s still a great proof of concept and a good way to learn how old oscilloscopes work. Check out the video after the break to see the laser scope in action.

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Sharpening Knives Using A Bread Slicer?

March 18, 2015 by James Hobson 19 Comments

[Joekutz] wrote in to tell us about his very interesting creation — a knife whetting machine, built from an automated bread slicer. Confused? So were we when we read the subject line!

Tired of sharpening knives by hand, [Joe] wanted to speed up the process. He recently saw our post on making a tool sharpening turntable out of a bread maker and figured, why not make one out of a bread slicer? We have no idea how you guys came up with these — finally some real hacks!

First he took apart the bread slicer and salvaged the motor, gears, and some of the electronics. He created an enclosure for it out of some laminate wood he had laying about and created a bearing axle for the disc from an old VCR. To control the speed he’s using a plain old light switch dimmer; not the most efficient but does the trick!

It uses sanding discs you can buy from any hardware store, and as you can see in the following video — it works pretty good according to the paper cutting test!

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Excuse Me, Sir. Do You Know How Fast Your Lathe Was Traveling Back There?

March 18, 2015 by Rich Bremer 26 Comments

When machining metal, it is important to know how fast the cutting tool is traveling in relation to the surface of the part being machined. This amount is called the ‘Surface Speed’. There are Surface Speed standards for cutting different types of materials and it is good practice to stick with those standards in order to end up with a good surface finish as well as maximizing tool life. On a lathe, for example, having a known target Surface Speed in mind as well as a part finish diameter, it is possible to calculate the necessary spindle speed.

Hobbyist [Paul] wanted a method of measuring his lathe’s spindle speed. Since spindle speed is measured in RPM, it made complete sense to install a tachometer. After browsing eBay for a bit he found one for about $20. His purchase came with the numeric LED display, a mounting bezel and the all important hall effect sensor. The Hall effect sensor measures changes in a magnetic field and in turn varies its output voltage. [Paul] fabbed up an aluminum bracket that supports the sensor just off of the rear of the lathe spindle. A magnet was then glued to the outside diameter of the spindle below the sensor. The once per revolution signal is generated every time the magnet passes the sensor while the lathe is running. The display was mounted to the lathe near eye height by means of another aluminum bracket and case.

After a little work, [Paul] can now keep a close eye on his spindle speed with a quick glance over at his new tachometer display while he’s turning those perfect parts! If this project tickles your fancy, you may want to check out this fantastic DIY tachometer or this one that uses a soundcard.

Mobile Lorm Glove Puts Texting Back Into Everyone’s Hands

March 16, 2015 by Sonya Vasquez 2 Comments

If you’ve been killing time texting or chatting with your pals via smart phone, odds are pretty good that you’re not giving much thought to the two senses that make it happen: your sight and your hearing. Those who are deafblind, however, cannot participate in these activities; and for many, the remote communication that most of us enjoy with our phones simply isn’t possible. Enter Berlin University of the Arts Design Research Lab. Here, they’ve developed the Mobile Lorm Glove, a haptics device that enables two-way remote communication via smart phone.

For the deafblind, Lorm is the tactile technique for communication. Lorm is a series of hand-tracing gestures that map to characters of the alphabet. To communicate with others, the gloved user can trace Lorm directly onto the pressure-sensitive inputs on the palm of the hand. To receive messages, small vibration motors on the back of the hand vibrate to indicate the message encoded in Lorm.

Originally, to communicate with the deafblind, we must first learn Lorm. With the Mobile Lorm Glove, however, we need only know how to send text messages, and the Lorm-decoding is handled with a look-up table running on our classic Atmega328 microcontroller. For the sharp-eyed, the back-side of the glove seems limited in its capability to transcribe continuous finger traces into discrete motor vibrations. However, with four shift-registers and 32 levels of motor-intensities, the designers address each motor with a technique called “funneling illusion” where continuous movement is simulated by gradually changing the intensity from motor to motor. For more tricks and details, take a look at their conference paper.

By wearing the glove, everyday communication can be made far easier with anyone with a smart phone. We’re jazzed that just a Bluetooth module, an Atmega328, and a collection of pressure sensors and motors can enable any cell phone user to circumvent the learning curve and open up a new conversation.

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Lift Kits For Car Jacks Do Exist

March 14, 2015 by Rich Bremer 72 Comments

When needing to change a tire or work under our vehicles we humans reach for a trusty jack. The standard jack in your trunk or mounted behind the seat of your truck works fine 99% of the time. But what happens when the vehicle in need of repair has a lifted suspension, raising the frame in relation to the ground and making the stock jack now too short?

Off-Road enthusiast [am4x4] had that problem and came up with a neat solution. He made a lift kit for a roll-around mechanics jack! He started with a 1.5 ton jack from Harbor Freight. This jack had 2 small casters in the rear and one wide roller in the front. This combination works great on concrete but [am4x4] needed this to work out in the dirt so a few mods were in order.

First the front roller was scrapped and replaced by two large 8 inch diameter tires. To get these to fit the bolt holes for the roller were enlarged to the same diameter as the wheel bearings. A new solid axle was then made from 5/8 inch solid rod. Those may look like pneumatic tires but they are actually solid rubber and only cost $6 each, also from Harbor Freight. These tires not only raise the jack up several inches but also increase the surface area contacting the ground. This better distributes the weight of the vehicle and prevents the jack from pushing itself into the ground.

In the back, the small stock casters were removed and replaced with larger, heavier duty ones. Even with the larger casters, the jack leans rearward. [am4x4] plans on making an extension to level the jack out but for now, it works well and is definitely a conversation piece at the off-road get togethers.

Replacing Dead Battery Pack Cells Saves You Some Coin

March 14, 2015 by Rich Bremer 43 Comments

No one will deny that cordless drills can be super convenient. Sure, they need to be charged once in a while but that’s not a big deal. The big deal is when the batteries no longer hold a charge. Buying a new battery pack from the drill OEM is not cheap. If you need several, it’s almost cheaper to buy a new drill/battery combo.

It is not uncommon for only one cell is bad in the battery pack. Getting a replacement cell makes economic sense. And at about $1 per cell, even replacing all of the cells in the pack is way cheaper than the alternatives. [ksickafus] had a battery pack that did not work and not only did he replace all the cells, he wrote a great instructable about it.

The process started by removing the cells from the plastic container. Since they were soldered together they came out in one unit. The cluster of cells was then laid down on a piece of paper and the perimeter of each cell was marked to document the cell orientation. Next, the leads connecting each cell to its neighbor were noted on the same sketch.

The new cells were then laid out on the template to make sure they were in the same orientation as the originals. [ksickafus] uses braided shielding as his new tabs to connect the cells together and learned from experience that flux is necessary for this type of repair. Once everything is soldered up, it’s time to re-assemble the cells in the plastic case and give it a charge. If you do this at home, make sure you keep an eye on it the first time so nothing goes wrong!

If replacing NiCd’s with NiCd’s isn’t cool enough for you, maybe popping some LiPo’s in your drill would be up your alley.