New Cable-Based Vise Improves Woodworking Workshop

May 25, 2015 by Rich Bremer 18 Comments

We are all aware of the typical wood shop vice, the type that is mounted underneath the workbench and takes forever to open and close by continuously spinning a large handle. These vises normally only open several inches due to the length of the operating screw. They are also not very wide because a cantilevered wide jaw would provide less force the further away it is from the center-mounted operating screw.

Wood worker [Andrew] wanted a very versatile and large vise for his shop. It needed to be wide, provide equal clamping force along the jaw and be able to hold very thick objects as well. One more thing, he wanted it to have a quick release clamping system so there would be none of that continuous handle spinning nonsense.

Spoiler Alert: [Andrew] did it! The end product is great but the interesting part is the journey he had taken along the way. There were 4 revisions to the design, each one making the vise just a bit better.

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Robot Camel Jockeys

May 25, 2015 by Elliot Williams 17 Comments

You might think we’re sinking to lowest-common-denominator, click-bait headlines like the rest of the online press. We’re not. The New York Times Video Notebook series has a story on camel racing that you’ve just got to see in the video after the break.

Previously, the camel races in Abu Dhabi had used small children as jockeys because they’re lightweight. Unfortunately, this lead to illegal trafficking of small children, mostly orphans. That won’t do. So they came up with a technological solution.

Strap a cordless drill with a purpose-built whip in the chuck onto the back of your camel. Add a car-remote keyfob to activate, and a two-way radio so that you can shout encouragement into your animal’s ear at just the right times. Now just chase the racers down the highway in an SUV and it’s like you’re there on the camel’s back!

We love the little silk suits that the drillbot-jockeys get to wear, but we’re not sure that cordless drills with walkie-talkies and remote controls count as “robots” really, because they don’t do anything autonomous. We think they’re more accurately described as “telepresence agents”.

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Handheld Belt Sander Converted To Bench Top Unit

May 24, 2015 by Rich Bremer 8 Comments

Having a basement or garage shop sure comes in useful for the home handyman. One downside to having a self-funded show is that you may not have every tool that you need. [unknownuser2007] had a hand-held belt sander and regularly used it to round off sharp corners on small parts instead of using it for its intended purpose; smoothing out long flat boards. It was typical for [unknownuser2007] to hold the sander in one hand and his work in the other while sanding his wooden parts.

This method of sanding was not very precise (or safe) so he decided it was time to do something about it and build a stand for the sander. The frame is built from 1/2 inch plywood, with pieces jig-sawn to fit the contour of the belt sander housing. After the frame was assembled, a dust collection system was made using an old vacuum attachment and some plastic sheet. The finished rig mounts solidly to the work bench and now allows [unknownuser2007] to use both hands to shape his creations.

As much as we love these types useful tool mods, on revision 2 we’d like to see an easily accessible on/off switch and a work support square to the belt. If you’re interested in more DIY sander solutions, check out this 20 inch disk sander.

Vintage Microammeter Now Tells Temperature

May 18, 2015 by Anool Mahidharia 10 Comments

[Craig] sent in this tip about a simple hack he built to convert an old analog micro-ammeter into a thermometer using a few parts. There’s a certain charm to retro analog meters, and there was enough space inside the old meter to accommodate the tiny breadboarded circuit and the three AA batteries to convert it into a cool looking centerpiece which is useful too!

He used the 3-pin MCP9700 analog temperature sensor connected to a LTC1541 – a combined comparator, op-amp and band gap reference voltage all rolled into one package. The thermometer displays 1uA per degree Celsius, has an output of 1mV per degree Celsius for external temperature monitoring / data logging, and draws just about 20uA. While the build itself is pretty simple, [Craig] took the time to walk through every design decision he made in the video after the break. This starts with the design for his circuit, and moves on to the selection of parts and their values. The video is a must-watch for anyone wanting to learn more about precision op-amp based designs.

The three batteries will drain over time, and a circuit like this one requires a stable reference voltage. That is taken care by the bandgap reference voltage from the LTC1541. This eliminates the use of additional voltage regulators, and allows the circuit to work from 4.5V down to about 3.3V. Check the video after the break to listen to [Craig] describe how it works. We’re not sure how quickly it responds to changes in ambient temperature since the sensor is enclosed inside the meter, so maybe some vents at the back, or bringing out the sensor might be a good idea.

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Smarter-than-wood Saw Blade Makes Perfect Foldable Joints

May 15, 2015 by Rick Osgood 53 Comments

[Andrew Klein] knows the pain of building drawers from plywood. It can be a pain to get all of the pieces measured and cut just right. Then you have to line them up, glue them together, and clamp them perfectly. It’s time-consuming and frustrating. Then one day it hit him that he might be able to make the whole process much easier using a custom saw blade.

The the video below, [Andrew] does a great job explaining how the concept works using a piece of paper. The trick is that the plywood must be cut in a very specific shape. This shape results in the plywood just barely being held together, almost as if it’s hinged. The resulting groove can then be filled with wood glue, and the plywood is folded over on itself. This folding process leaves no gaps in the wood and results in a strong joint. Luckily this special shape can be cut with a specialized saw blade.

This new process removes the requirement of having five separate pieces for a drawer. Instead, only four cuts are needed on a single piece of square plywood. The corners are then removed with a razor blade and all four sides are folded up and into place. [Andrew] shows that his prototype blade needs a little bit of work, but he’s so hopeful that this new invention will be useful to others. Continue reading “Smarter-than-wood Saw Blade Makes Perfect Foldable Joints” →

Move Over Red Bull, Hot Wire Foam Cutter Now Gives You Wings

May 14, 2015 by Rich Bremer 13 Comments

Not many people will argue with flying RC airplanes is super fun. One big bummer is when a crash damages a part beyond repair. Sure, the RC pilot could keep buying replacement parts but doing so will add up after a while. RC plane builder and general guy with a cool name, [HuckinChikn], decided to build a hot wire foam cutter so making replacement wings would be quick and cheap.

The actual hot wire part is nothing special, just some wire pulled taut across a frame and a 24 vdc power supply pumping out current and heating the wire so it melts any foam in its path. The unique part of the build is that one side of the hot wire frame is secured in place and only allowed to pivot about that point. The other side of the frame traces an airfoil-shaped pattern. This setup allows [HuckinChikn] to make tapered wings. The difference between a straight wing and a tapered wing is similar to that of a cylinder and cone.

Check out the video after the break for a quick demonstration how easy it is to make a wing when you have the right tool!

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Hacking Amazing Soldering Features Into The Already Great Weller WMRP

May 11, 2015 by Anool Mahidharia 35 Comments

Weller, the German soldering tools manufacturer, has a nice range of micro soldering irons (pencils) designated as the WMRP series. These are 12V, 40 W or 55W units with a 3 second heat up time, and allow quick tip exchange without needing any tools. [FlyGlas] built a neat soldering station / controller for the WMRP series based around an ATMega microcontroller running Arduino.

It’s packed with most of the features you see in a professional rig.

low offset op amp for soldering tip temperature measurement with type c thermocouple
cold junction compensation using the PTC (KTY82-210) included in the WMRP soldering pencil
input voltage measurement
soldering pencil current measurement
recognizing if the soldering pencil rests in the stand (–> standby)
3 buttons to save and recall temperature values
rotary encoder to set soldering temperature
illuminated 16×2 character LCD module
USB for debugging and firmware update
4mm safety socket for +12V power input and a protective earth socket for connection to ESD protection

A PWM signal from the microcontroller controls the load current using a MOSFET. Load current is measured using a Hall Effect-Based Linear Current Sensor – ACS712. The corresponding linear output voltage is buffered and slightly amplified using AD8552 zero drift, single supply, RRIO Dual Op Amp before being sent to the microcontroller ADC input. To ensure ADC measurements are accurate and stable, a low noise precision voltage reference – ADR392 is used. Another precision resistive voltage divider allows input voltage measurement. The supply input has over-current and reverse voltage protection. A set of buttons and a rotary encoder are connected to the microcontroller to allow settings and adjustments. An analog section measures the thermocouple voltage from the soldering pencil as well as the stand-by switch status. The handle has an embedded reed switch that is activated by a magnet in the support stand which puts it into stand-by mode. Another analog section performs cold junction compensation using the PTC sensor within the soldering pencil.

The Git repo contains the initial Arduino code which is still a work in progress. While the hardware source files are not available, the repo does have the pdf’s, gerbers and BOM list, if you want to take a shot at building it. Check a demo video after the break. Thanks [Martin] for sending in the tip.

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