Full-Auto Crossbow Rocks and Rolls on Rubber Bands and Electric Drill

You’ve got to enjoy any project where the hacker clearly loves what he or she is doing. And when the project is as cool as a motor-driven, rubber band powered, fully automatic crossbow, it’s hard not to laugh along.

A full-auto crossbow is no mean feat, and it took a man with a love for rubber-powered firearms to get it right. [JoergSprave]’s design is based on a rack-and-pinion system and executed mainly in plywood. The main pinion gear is a composite of aluminum and wood, in a bid to increase the life of the mechanism and to properly deal with the forces involved. The pinion, turned by a powerful electric drill, drives the rack back and locks the carrier under the 30-bolt magazine. A rubber-powered follower forces a bolt down and a cam on the pinion trips the sear, the bolt is fired and the cycle continues.

We slowed the video down a bit and it looked to us like the cyclical rate of fire was about 7 rounds per second, or a respectable 420 rounds per minute. Pretty powerful, too, and the accuracy isn’t bad either.

We’ve seen [Joerg]’s inventions before, like this soda bottle Gatling arrow launcher, or his ridiculous machete launcher. We hope he keeps having fun and letting us watch.

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How To Drill A Curved Hole

Next time you’re renovating and need to run some cables around corners in you walls, save yourself some frustration by building [izzy swan]’s corner drilling rig. It’s something akin to a custom tunnel boring machine but on a small scale.

drill-a-curved-holeStarting with a piece of steel, [izzy] traced and cut out a 90 degree curve with an attached arm that will allow it to rotate from a central block. He then grabs a random drill bit and attaches it to a flex shaft which is secured to the leading point of the steel curve. To complete the handy setup the entire rig is bolted to a block that will clamp over the corner stock.

As it stands, it takes some elbow grease to get the drill through, but it’s not a purpose built setup. On a second demonstration, the flex shaft breaks, but the idea is there. Now, [izzy] advises that this is most easily accomplished when re-framing walls with no drywall obstructing your drill, but the concept for this rig could nonetheless prove handy for welding, grinding, and so forth along any angled curve.

If instead you want to push your carpentry skills to their limits, build a wooden Vespa.

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Likely Everything You Need To Know Before Adopting A Drill Press

Oh sure, the thought of owning a happy whirring drill press of your very own is exciting, but have you really thought about it? It’s a big responsibility to welcome any tool into the home, even seemingly simple ones like a drill press. Lubricants, spindle runout, chuck mounts, tramming, and more [Quinn Dunki], of no small fame, helps us understand what it needs for happy intergration into its new workshop.

[Quin] covers her own drill press adventure from the first moments it was borne into her garage from the back of a truck to its final installation. She chose one of the affordable models from Grizzly, a Washington based company that does minimal cursory quality control on import machinery before passing on the cost to the consumer.

The first step after inspection and unpacking was to remove all the mysterious lubricants and protectants from the mill and replace them with quality alternatives. After the press is set-up she covers some problems that may be experience and their workarounds. For example, the Morse taper on the chuck had a few rough spots resulting in an incomplete fit. The chuck would work itself loose during heavier drilling operations. She works through the discovery and repair of this defect.

Full of useful tips like tramming the drill press and recommended maintenance, this is one of the best guides on this workshop staple that we’ve read.

 

Frankensteined Cordless Drill Lives Again

With tools, especially cordless tools, you’re going to pay now or pay later. On one hand, you can spend a bunch of money up front and get a quality tool that will last a long time. The other option is purchasing a cheap cordless tool that won’t last long, having to replace it later and thus spending more money. With cheap cordless tools it is common for the battery to fail before the physical tool making that tool completely unusable. Sure, another battery could be purchased but sometimes they cost just as much as the tool and battery combo originally did. So what’s a cordless tool user to do?

[EngergySaver] had a set of DeWalt cordless tools with a bunch of working batteries. He also had a cheap drill where the battery had died. His bundle of tools included two flashlights, one of which the case physically broke in half, probably from a clumsy drop. Instead of tossing the broken flashlight pieces in the garbage, [EngergySaver] kept them around for a while. Then one day he had the idea of combining the base of the broken DeWalt flashlight with the top of the old battery-less drill. He had the parts so why not?

The battery pack was 18 volt and the cheap drill expected 16.8 volts. [EngergySaver] figured the voltages were close enough and decided not to worry about the difference during his hack. He started by disassembling both the drill and flashlight down to the bare plastic housings. He marked an appropriate place to splice the handles and made some cuts. After the wiring was spliced together and the tool casings reassembled, a piece of sheet metal was cut and bent around the handle at the joint between flashlight and drill. Hose clamps hold the sheet metal tight around the handles, keeping the new hybrid tool together. And although we’re not crazy about the sheet metal and hose clamp method, it seems to be working just fine. With a little work and ingenuity [EngergySaver] resurrected an old tool for our favorite price; $0.

DIY Mini-Drill Would Make Mad Max Proud

mini-drill

That’s not a prison tattoo gun up there, it’s [Szabolcs] DIY mini drill. Hackaday has been on a bit of a DIY tool kick lately – with improvised saws, grinders, and grinders converted to saws, among other things. We haven’t had any DIY drills yet, though. [Szabolcs] needed a drill for his home-made printed circuit boards. Usually a Dremel or similar rotary tool is pressed into service for drilling PCBs. However, for some reason he didn’t have access to one. [Szabolcs] called upon his inner MacGyver and built a drill from parts he had on hand.

Every drill needs a chuck, or at least a collet holder. This drill’s chuck is sourced from a drafting compass. Long ago in the dark ages before CAD, mechanical drawings were manually drawn up. Companies employed entire drafting departments to draw designs, blueprints, and schematics. These draftsmen used the compass to create accurate circles and arcs. [Szabolcs] re-used the lead holder from the compass as a chuck for his drill. A 540 or 550 brushed sealed endbell can motor, common to the R/C cars spins the drill up. We originally thought [Szabolcs] used an Erector or Meccano set piece as a shaft coupling. The truth is it’s the internals of a Euro style terminal strip. A small tactile button is used to activate the motor. Some electrical tape wrapped around the motor holds the button in place. The tape also makes sure that the user isn’t cut by the sheet metal field ring wrapped around the can. Power for the system can come from just about anywhere, though [Szabolcs] says he uses the 12v rail of an old ATX power supply.

Electric Bicycle Hack is Hilariously Simple

Necessity may be the mother of invention, but limited resources give birth to some of the best hacks. [joejoeboom’s] 5-minute electric bike conversion probably can’t drive you into the next town, but it can scoot you around your neighborhood.

[jojoeboom] found a cordless drill at a local hardware store for $15, which he simply zip-tied to the bicycle’s frame. He positioned the drill so the chuck pressed firmly against the side of the bicycle’s rear wheel, creating a simple friction drive system. To create a throttle, [joejoeboom] strapped a spare hand brake to the handlebar and wrapped the brake’s cable around the drill’s trigger. Several carefully placed zip ties hold everything in place and allow the cable to tug at the trigger when the hand brake is squeezed.

Watch the bike poking around in a video below, and for some extreme contrast check out the 102-mph bicycle build from earlier this summer.

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60,000 RPM vacuum powered rotary tool was 3D printed

vacuum-powered-rotary-tool

The whining of the turbines in the 3D printed pneumatic rotary tool might make your teeth hurt. When [Axodus] tipped us off about it he mentioned it sounded like a 747 taking off. But we hear a dentist’s drill when watching the demo video.

[Richard Macfarlane] published his design if you want to try building one for yourself. But you will need to do some machining in addition to printing the enclosure and the pair of turbines. The shaft of the tool needs to fit the bearings precisely. It accepts a center blue spacer with a red turbine on either side. This assembly is encapsulated in the two-part threaded blue body which has a flange to friction fit with the shop vacuum hose. The business end of the machined shaft was designed and threaded to accept the collet from a Dremel or similar rotary tool.

We wonder how much work it would be to re-engineer this to act as a PCB drill press?

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