Custom Machined Triple Threat Slingshot

Time was when a lad in need of a ranged weapon would hack a slingshot together out of a forked tree branch and a strip of inner tube. Slingshot design has progressed considerably since [Dennis the Menace]’s day, but few commercially available slingshots can match up to the beauty and functionality of this magnificently machined multipurpose handheld weapon system.

Making it clear in his very detailed build log that this is but a prototype for a design he’s working on, [Gord] has spared little effort to come up with a unique form factor that’s not only functional as a slingshot, but also provides a few surprises: a magazine that holds nine rounds of ammo with magnets; knuckle protection on the hand grip that would deal a devastating left hook; and an interchangeable base that provides a hang loop or allows mounting a viciously sharp broadhead hunting arrow tip for somewhat mysterious purposes. There’s plenty to admire in the build process as well – lots and lots of 6061 billet aluminum chips from milling machine and lathe alike. All told, a nice piece of craftsmanship.

For a more traditional slingshot design with a twist, check out this USB-equipped slingshot that talks to Angry Birds. And when your taste in slingshots run more toward the ridiculously lethal, [Jörg Sprave]’s machete launcher never disappoints.

[Thanks Leslie!]

Making A Wooden Bowl Without A Lathe

Typically, when creating a wooden bowl a crafts person would do so on a lathe. A chunk of wood would be bolted to the head stock and the bottom of the bowl turned to an appropriate shape. Then the half-bowl-shaped wood is flipped around on the lathe so that the material on the inside of the bowl can be removed. This traditional method of bowl turning requires a lathe, turning tools, and the serious technique and skill required for the task.

The master maker of weird wood working tools, [Izzy], decided to make a wooden bowl without the use of a lathe. He created a unique fixture to cut the shape of the bowl on a table saw, a piece of equipment that is a bit more common for the average DIYer to have. The fixture itself is made of wood and supports a standard hand drill in a vertical position. The soon-to-be bowl is bolted to the drill and hovers just above the table saw blade. The table saw is turned on and the fixture allows the work piece to rock back and forth creating the bowls outside shape. The drill rotates the piece so that the contours are consistent around the bowl.

The bowl is then flipped over and re-attached to the drill. This time to cut the inside of the bowl, the fixture is locked in the vertical position and the wood is dropped straight down on the spinning blade while being rotated. The saw blade cuts a perfectly hemispherical cavity in the wood. The final bowl looks great after a little sanding and an application of oil. Check out the video after the break.

This isn’t the first time [Izzy’s] projects have been here on Hackaday, check out his DIY Band Saw and Wooden Sphere Cutter.

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Miniature Cannon Packs a Punch, Shows off Manual Machining Skills

CNC machine tools are getting ever more affordable for the amateur machinist, and they’re an enabling technology for many projects. But you’ve got to respect the old school approach to turning hunks of metal into finished parts with no computer control. [Ticktock34] shows off his skills on a WWII vintage manual lathe with a photo album of his .75 caliber miniature black powder cannon build. What starts as a 3″ diameter actuator from a front end loader ends up as a beautiful replica of a full-sized cannon, along with a half-filled barrel of nicely blued scrap metal. Particularly impressive is the nicely proportioned ball end, cut by hand with no more instrumentation than a set of calipers. [Ticktock34] also shares a few tips for getting the trunnions exactly squared and aligned.

Good looking, and functional – stay tuned after the break for a video with the impressive blast from a test firing – with only a quarter charge of powder, mind you.

Want something a little safer for the kiddies and less likely to result in a visit from the police? Perhaps this PVC pirate cannon is more your speed.

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2D Printed Tachometer For A Lathe

If you ever wanted a reason to have DC lighting pointed at the spinny part of your mill and lathe, [Bill] tells a great story. One day, he noticed the teeth on his lathe chuck would change color – red, then blue, then red. His conclusion was the fluorescent lights above his workbench was flashing, as fluorescent lights normally do.

Imagine if the teeth on [Bill]’s chuck weren’t painted. They would appear stationary. That’s usually a bad thing when one of the risks of using a lathe is ‘descalping.’ Buy an LED or incandescent work light for your shop.

This unique effect of blinking lights got [Bill] thinking, though. Could these fluorescent lights be used as a strobe light? Could it measure the RPM of the lathe?

And so began [Bill]’s quest for a 2D printed lathe tachometer. The first attempt was to wrap a piece of paper printed with evenly space numbers around the chuck. This did not work. The flash from his fluorescent bulb was too long, and the numbers were just a blur. He moved on to a maximum-contrast pattern those of us who had a ‘DJ phase’ might recognize immediately.

By printing out a piece of paper with alternating black and white bands, [Bill] was able to read off the RPM of his chuck with ease. That’s after he realized fluorescent lights blink twice per cycle, or 120 times a second. If you have a 3″ mini-lathe, [Bill] put the relevant files up, ready to be taped to a chuck.

Hackaday Links: May 31, 2015

Back in the mid-70s, [Paul Horowitz] (who has an incredible Wikipedia entry, by the way) started teaching Physics 123 at Harvard. Simple electronic circuits, solving problems with silicon; simple stuff like that. His lecture and lab notes started getting a following, and after Xeroxing a few dozen copies, he realized he had written a book. It was The Art of Electronics, and Ladyada interviewed this master of hand drawn schematics. A great interview and great camera work, too.

Like hackathons? How about one at CERN? It’s happening October 2 through October 4. The aim this year is to have a humanitarian and social impact thanks to technology. The projects last year were very good; everything from cosmic ray detectors to a $10 inflatable fridge for field operations.

You want viral advertising for your movie? This is how you do viral advertising for your movie. It’s Hackerman’s Hacking Tutorials, and we’d really like to know how they did the 80s graphics with modern computers. It’s not like you can just go out and buy a Video Toaster these days…

Previously available only through group buys, the Flir Lepton module is now available at Digikey.

We have hit the singularity. We have stared into the abyss, and the abyss has stared into us. There was a kickstarter to fund a trailer for another, bigger kickstarter. Relevant xkcd right here.

The Tymkrs had a lamb roast, and what better way to do that than with a huge lathe? Put some charcoal on the ways, turn it at a low RPM, and eventually you’ll have a meal. Bonus points for the leaf blower manifold, a gold star for carving it with a sawzall.

Pneumatic Pen Gun is Fit for James Bond

The James Bond franchise is well-known for many things, but perhaps most important to us hackers are the gadgets. Bond always had an awesome gadget that somehow was exactly the thing he needed to get out of a jam. [hw97karbine’s] latest project would fit right into an old Bond flick. He’s managed to build a single-shot pellet gun that looks like a pen.

[hw97karbine] started out by cutting the body from a tube of carbon fiber. He used a hacksaw to do the cutting, and then cleaned up the edges on a lathe. A barrel was cut from a piece of brass tubing with a smaller diameter. These two tubes will eventually sit one inside of the other. A custom front end cap was machined from brass. One end is ribbed and glued into the carbon fiber tube. The barrel is also glued to this end of the front cap, though it’s glued to the inside of the cap. The other end of the cap has 1/8″ BSP threads cut into it in order to allow for attachments.

A rear end cap is machined from Delrin. This piece also has a Delrin piston placed inside. The piston has a small piece of rubber used as a gasket. This piston valve is what allows the gun to operate. The rear cap gets glued into place and attached to a Schrader valve, removed from an automotive tire valve stem.

To pressurize the system, a bicycle pump is attached to the Schrader valve. This pushes the piston up against the barrel, preventing any of the air from escaping. The piston doesn’t make a perfect seal, so air leaks around it and pressurizes the carbon fiber tube. The Schrader valve prevents the air from leaking out of the pen body. A special machined button was threaded onto the Schrader valve. When the button is pressed, the air escapes; the sudden pressure imbalance causes the piston to shoot backwards, opening up a path for the air to escape through the barrel. This escaping air launches the projectile. The whole process is explained better with an animation.

Now, the question left in our mind: is this the same pressure imbalance concept that was used in that vacuum pressure bazooka we saw a couple years back?

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Mini Wood Lathe Made of….. Wood?

When someone says ‘wood lathe’ the average person would think of a lathe used for turning pieces of wood into ornate shapes. But what if that lathe was also made of wood. Would that be a wood wood lathe? Instead of wondering the answer to that very unimportant question, young 15 year-old [laffinm] decided to actually build a wood wood lathe from plans he found in a magazine.

As you would expect, a 15 year-old’s budget is certainly not going to be very large. [laffinm] started by gathering plywood scraps left over at construction sites. The lathe bed, head stock, tail stock, tool rest and motor mount are all made from 3/4″ plywood. The tool rest and tail stock have knobs that allow loosening of each part so that they can be moved to any location on the bed.

Out back, [laffinm] made his own live center for the tail stock out of a chuck and bearing assembly that he pulled from an old drill. The tail stock supports were drilled out to fit the bearings which were epoxied in place. The live center and tail stock combination supports the right side of the work piece that is being turned on the lathe.

In the end the lathe came out pretty darn well. We here at Hackaday love projects that make use of recycled parts and this project sure does that as most of the parts were scavenged or obtained for free with the only exceptions a v-belt and some nuts and bolts. If you’d like to see the build process in detail, [laffinm] has a very complete Instructable with 3 build videos, the first of which you can find after the break.

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