Hands-On Othermill Review Grinds Out Sparkling Results

We’ve been on the lookout for alternatives to chemically etching circuit boards for years. The problem has been that we don’t particularly want to devote months of or lives learning how to build precision CNC mills. Off in the distance there may be an answer for that quandary if you don’t mind parting with twenty-two Benjamins. Sure, it’s a heck of a lot more expensive than toner transfer and cupric chloride, but the Othermill can be purchased right now (in your hands a few months later) and after reading this in-depth review we are a bit less hesitant about opening our wallets for it.

othermill-review-thumbIt’s a tome of a review, but that means there’s something for everybody. We especially enjoyed seeing the 10 mil board shown here which took about 1-hour to mill. Considering it has also been through-hole drilled we’d put that on part with the time it takes to etch a board. There are obvious places where the traces are not perfectly smooth (not sure if that’s burring or over-milling) but they are not broken and the board’s ready to be populated.

Alignment is something of an issue, but the Othermill isn’t limited to PCBs so we’d recommend designing and milling your own alignment bracket system as an early project.

Who isn’t envious of custom-builds that can get down to 10-mils, like this beauty from 2013. Our hopes had been sparked when Carbide 3D came onto the scene. We’re still optimistic that they will make a big splash when they start shipping preorders in a few months.

As this review proves, Othermill is already out in the wild with a 6-8 week wait before shipping. We saw it in action milling multiple materials at the Hackaday Omnibus Lauch Party and were duly impressed. Price or waiting-period aside we’re going to hold off until the software options expand beyond Mac-only; either Othermill will add support or someone will come up with a hack to use traditional CNC software. But if you count yourself as a subscriber to the cult of Apple the software, called Otherplan, does get a favorable prognosis along with the hardware.

Already have an Othermill sitting on your bench? Let us know your what you think about it in the comments below.

Bonus content: [Mike Estee], CTO of Othermill just gave a talk last night about how he got into making mills and the challenges of building something with super-high-precision. Sound isn’t good but the talk is solid. Hackaday’s [Joshua Vasquez] also gives a talk on the video about building an SPI core for FPGA. These talks are one of the Hardware Developer’s Didactic Galactic series which you really should check out if you’re ever in the San Francisco area.

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DIY Car Wheel Bearing Puller

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‘.

BearingPuller2

[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

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?

[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?

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.

Lift Kits for Car Jacks do Exist

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.