An Improved Table Saw Fence With Threaded Rod

Back in the bad old days, table saw fences were terrible. You would have to measure the top and bottom of the fence before each cut, just to make sure the fence was square to the blade. In the 1970s, [Bill Biesemeyer] invented a better table saw fence, one that was always square, and included a measuring tape, right on the table saw.

[Jer] wanted an upgrade for his table saw and came up with what might be the next evolution of the table saw fence. It will always produce a square cut, but unlike the 1970s version, this fence has repeatability. If you rip a board to 1″, move the fence, come back to it after a month, and try to rip another board to 1″, those two boards will be exactly the same width.

The secret to this repeatability is a threaded rod. On the front of the fence is a big, beefy piece of threaded rod with 16 threads per inch. On the fence itself is two nuts, cut in half, welded to the guide, with a lever and cam to lock them in place.

When the lever is up and the nuts are disengaged from the threaded rod, the fence easily moves from one side of the table to the other. When the fence is locked down, it locks to the nearest 16th of an inch, and only the nearest 16th of an inch. While that may seem a little large for a relatively expensive tool, this is wood we’re talking about here. There’s not much reason to make the resolution of this fence any smaller; wait until the humidity changes and you’ll have a piece of wood that’s the desired dimension.

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DIY Automatic Chain Cleaning Machine

Spring is here and it’s time to pull the bikes out of the shed. One think that is often overlooked is bicycle maintenance. No one wants to be that guy walking his bike home after a part failure renders the bike unrideable. One portion of proper bike maintenance is cleaning the chain. A contaminated bike chain can wear quicker, not be as flexible, hinder shifting and increase wear to the drivetrain cogs. Tired of sitting there cleaning his chain with a tooth brush, [Ally] built a washing machine for bike chains.

This machine is quite simple, it’s a plastic box full of turpentine and dish detergent. The chain is submerged in the liquid and a lid is put on the box. At the local hobby store, [Ally] purchased a small gearbox and motor assembly. Powered by a 5vdc wall wart, the output shaft of the gearbox spins a crank that in-turn agitates the box, chain and cleaning liquid. After about 5 minutes the chain is free of grit and gunk. Not bad for a few dollars, spare parts and a little bit of time. Check out the video of it in action after the break.

While you’re waiting for your chain to be cleaned you should work on making your bike pedal in both directions.

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Showing an AVR Programmer Who’s Boss

[Bogdan] makes a good point. When you use a dev board you get programming, debugging, power sourcing, and usually a UART. When you go to the trouble of hooking up a programmer why don’t you get the same thing? Astutely, he points out that all you usually get with programmers is programming. So he set out to add features to the hardware he uses to program XMEGA.

The first part of the trick hinges on his use of PDI programming. This is slightly different from ISP programming. Both use a six-pin connector cable but with PDI two of these pins are unused. He took this opportunity to reroute the chip’s TX and RX pins through the cable, which now gives him an avenue to use a UART-to-USB adapter without adding any cables to his target board. Rather than add a second USB cable he rolled a USB hub into the mix. An LM1117 regulates the 5V USB rail down to 3.3V as a source for the target board.

The programmer being used is an Atmel ICE. As you might imagine he didn’t want to make permanent alterations to it. His modifications are all handled externally, with one IDC cable connecting the programmer to his added circuitry and another headed off to the target board. For now he’s jumpering RX/TX to the programming header but plans to route the signals on future PCBs.

Homemade 3D Carving Duplicator

[Frank] is a guitar builder and has to make a quantity of acoustic guitar bridges that wouldn’t make sense to do manually by hand each time. He wanted a way of duplicating bridges quickly and precisely but he didn’t want to go to a CNC machine. Instead, he build a 3D duplicating machine.

The machine has 3 perpendicular axes, just like a milling machine. Mounted to the Z Axis is an air powered spindle that can reach 40,000 RPM. All 3 axes are moved by the operators hands. Normally, free-hand cutting something like this would be very difficult. [Frank’s] solved this in his machine by using a stylus that is offset from the cutting bit. The stylus is the same effective length and diameter of the cutting bit and is guided over a finished bridge pattern. While the stylus is tracing the pattern, the spindle and bit are removing material from a bridge blank. The stylus is continually moved over the entire pattern bridge until the spindle is finished carving out a new bridge out of the blank.

To aid in lifting the heavy Z Axis and spindle, [Frank] added a counter balance to make tracing the pattern extremely easy. Once the new bridge is carved, it only requires minor sanding to remove the tool marks before being installed on a guitar! [Frank] admits his linear bearings and rails are very rigid but also very expensive. If you’re interested in a less-expensive 3D duplicator, check out this project.

Robo Foam Cutter Makes Short Work of your Foam Rolls

Tired of cutting your foam sheets down to size? [jgschmidt] certainly was, and after one-too-many hours cutting foam manually, he built himself a machine that cuts sheets automatically, and he guides you through the process step-by-step.

[jgschmidt’s] build is a clever assembly of stock parts acquired from ServoCity. That’s a nice touch, considering we don’t often see their components in quick hacks. With a stepper to feed more foam, and a stepper to drive the blade mechanism, the device can consistently cut foam from a roll to desired lengths.

The blade mechanism consists of two exacto blades fixed nose-to-nose such that the machine can cut on both forward and reverse sweeps. While we’ve certainly seen some stellar past foam cutter builds, we can’t resist drooling over the speedy throughput of [jgschmidt’s] machine as it cuts on both forward and back-strokes. Finally, when the blades dull, they can be swapped out for a few dime’s worth of new parts.

Many of the steps in [jgschmidt’s] build are laudably practical with a “get it done” attitude. From hot-glued wire insulation to the double-edged blade formed from exacto knives, we’re thrilled to see him take a few pieces off the shelf and few pieces off the web and build himself a new workshop tool. Perhaps the neatest feature of this hack is its ability to rapidly transform a raw material into numerous repeatable, useful forms for his customers.

via [Instructables]

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How To Properly Crimp Electronics Connectors

Putting crimp connectors on wires is one of the most tedious things you’ll do. It’s not easy, either, unless you have some practice. Before you start digging in to a pile of connectors, crimp terminals, and wire, it’s a good idea to know what you’re getting into and Gogo:tronics has a great tutorial on how to crimp electronics connectors.

Crimping connectors onto wires requires the right tool, and the most important for this task is – surprise – the crimping pliers. These pliers press the crimping wings of the connector into each other, a task made much easier on the non-ratcheting pliers if you use a rubber band to hold the jaws of the crimping pliers open just enough to hold a crimp connector.

The general theory for crimping all types of connectors is to strip a little bit of insulation off the wire. Then, put the connector into a suitably sized space in the jaws, insert the wire, and crimp it down. For non-ratcheting pliers, it’s suggested the connector be re-crimped with the next smallest hole in the jaws.

There are a few connector-specific tips for the most common connector types, too. Dupont connectors – those flat, black connectors with a 0.1″ pitch – go together like you think they would, but for larger connectors – VH and XH-style – it’s important to use the right wire gauge and not to squish the square female part of the connector.

3D Printed Pogo Pin Programmer

The new hotness for Internet of Things hardware is the ESP8266. Alone it can connect to a WiFi network, but it doesn’t really have a lot of output options. Paired with an ATMega, and you really have something. That’s the philosophy behind the WIOT board, and when [Chris] was assembling these boards, he needed a way to flash firmware. The board has an unpopulated ISP header from the assembler, so pogo pins are the answer. How do you make a pogo pin jig? With a 3D printer, of course.

The ISP header wasn’t populated to give the board a slim profile, but this means a jig of sorts would be needed to program the WIOT. The first attempt was buying a few pogo pin adapters from Tindie, but this was terribly uncomfortable to hold while the board was being programmed.

To fix this problem, a small clip device was rigged up, printed out, and used for programming. Interestingly, this clip has a very deep throat, and a few holes used for bolting on a separate programmer. This shows a lot of forward thinking: the programmer can be reused for different boards with completely different layouts and programmers. If the next revision of the WIOT needs a JTAG header to program the micro, the problem of programming it is already covered.