When all you have is a hammer, every problem is a constant quest for an even better hammer, as the popular saying goes. At least, that seems to be [Ebenisterie Éloïse]’s situation. She wanted a deadblow hammer that not only had an aesthetically pleasing wood and brass construction, but also one that included adjustable dampers to make sure that each hammer swing is as efficient as possible.
For those unfamiliar with specialty hammers, dead blow hammers typically have some movable mass such as sand or lead shot within the hammer head. This mass shifts forward when the hammer strikes an object, reducing rebound of the hammer off of the object and transferring more energy into each strike. This hammer omits a passive mass in favor of four custom-machined brass tubes, each of which holds a weighted fluid, a spring, and brass weight. Each piston acts as a damper in a similar way to a shock absorber on a vehicle, and a screw and o-ring at the top of each one allows them to be adjustable by adding different weight fluids as needed. Some detailed testing of the pistons shows a marked improvement over any of the passive mass varieties as well.
Not only is this an incredible amount of detail and precision for a tool that is often wielded in a non-precise way (at least among those of us for who aren’t skilled craftspeople), but it is also made out of wood, leather, and brass which gives it an improved look and feel over a plastic and fiberglass hammer that is typical of most modern deadblow hammers. It even rivals this engineer’s hammer with its intricate custom engraving in craftsmanship alone.
Continue reading “Adjustable, Piston-Damped Hammer”
With reflow soldering, sometimes close is good enough. At the end of the day, the home gamer really just needs a hot plate or an old toaster oven and a calibrated Mark I eyeball to get decent results. This exhaust fan-equipped reflow oven is an attempt to take control of what’s perhaps the more challenging part of the reflow thermal cycle — the cool down.
No fan of the seat-of-the-pants school of reflow soldering, [Nabil Tewolde] started with a cast-off toaster oven for what was hoped to be a more precise reflow oven. The requisite temperature sensors and solid-state relays were added, along with a Raspberry Pi Zero W and a small LCD display. Adding the cooling assist started by cutting a gaping hole cut in the rear wall of the oven, which was then filled with a short stretch of HVAC duct and a stepper-controlled damper. The far end of the duct was fitted with a PC cooling fan; while it seems sketchy to use a plastic fan to eject hot air from the oven, [Nabil] says the exhaust isn’t really that hot by the time it gets to the fan. At the end of the reflow phase of the thermal profile, the damper opens and the fan kicks on, rapidly cooling the oven’s interior.
Unfortunately, [Nabil] still needs to crack open the oven door to get decent airflow; seems like another damper to admit fresh air would help with that. That would complicate things a bit, but it still wouldn’t be as over-the-top as some reflow builds we’ve seen. Then again, that calibrated eyeball thing can work pretty well too, even without a toaster oven.
Continue reading “Exhaust Fan-Equipped Reflow Oven Cools PCBs Quickly”
In our vernacular, bricking something is almost never good. It implies that something has gone very wrong indeed, and that your once-useful and likely expensive widget is now about as useful as a brick. Given their importance to civilization, that seems somewhat unfair to bricks, but it gets the point across.
It turns out, though, that bricks can play an important role in 3D-printing in terms of both noise control and print quality. As [Stefan] points out in the video below, living with a 3D printer whirring away on a long print can be disturbing, especially when the vibrations of the stepper motors are transmitted into and amplified by a solid surface, like a benchtop. He found that isolating the printer from the resonant surface was the key. While the stock felt pad feet on his Original Prusa i3 Mk 3S helped, the best results were achieved by building a platform of closed-cell packing foam and a concrete paver block. The combination of the springy foam and the dampening mass of the paver brought the sound level down almost 8 dBA.
[Stefan] also thoughtfully tested his setups on print quality. Machine tools generally perform better with more mass to damp unwanted vibration, so it stands to reason that perching a printer on top of a heavy concrete slab would improve performance. Even though the difference in quality wasn’t huge, it was noticeable, and coupled with the noise reduction, it makes the inclusion of a paver and some scraps of foam into your printing setup a no-brainer.
Not content to spend just a couple of bucks on a paver for vibration damping? Then cast a composite epoxy base for your machine — either with aluminum or with granite.
Continue reading “Bricking Your 3D Printer, In A Good Way”
Some neurological disorders, like Parkinson’s disease, can cause muscle tremors which can get worse as time goes along. In the beginning it may not be too difficult to manage, but as the disease progresses the tremors get worse and worse, until day-to-day movements are extremely difficult. Even picking up a fork or pouring a glass of water becomes nearly impossible. Some helpful tools have been designed to limit the impacts of the tremors, but this new device seeks to dampen the tremors directly.
A research team from Fresno State has been developing the Tremelo, which is a hand stabilizer that straps onto the arm of a person suffering from tremors. It has sets of tuned mass dampers in each of two enclosures, which rapidly shift the weights inside to counter the motion of the wearer’s tremors. The device has already shown success in 36 trial patients and does an incredible job at limiting the amount of tremors the user experiences, and also has a bonus of being non-invasive for the wearer.
The team has successfully trialed the program, but is currently seeking funding on Indiegogo. The project seems worthwhile and is a novel approach to a common problem. In the past, devices (admittedly with a much cheaper price tag) try to solve the problem externally rather than in the direction that the Tremelo has gone, and it’s a unique idea that shows a lot of promise.
Continue reading “Controlling Tremors As They Happen”
No matter what material you work with, the general rule is that with machine tools, the heavier, the better. Some people can’t afford or don’t want big tools, though, even with their natural tendency to reduce vibrations. That doesn’t mean something can’t be done to help the little tools, like reducing vibration in a contractor-grade table saw.
This one might seem a little outside the usual confines of the hackosphere, but nobody can doubt [Matthias Wandel]’s hacker chops and he really shows off his problem-solving skills with this one. His well-worn contractor-style table saw has had more than a few special modifications over the years, some of which left it with a shimmy sufficient to vibrate workpieces right off the table. He fashioned a friction damper for the saw’s motor from wood, complete with ball and socket joints to allow full movement of the blade height and angle. That didn’t quite do the trick, but his incremental approach finally found the right combination of factors, and the video below shows a saw now stable enough to balance a nickel.
If the name seems familiar but you just can’t place the hacks, check out [Matthias]’s recent wooden domino extruder, his shortcuts to tapping wood, or of course his classic wood gears layout software.
Continue reading “A Fix For The Lightweight Machine Tool Shakes”