This day in history. Sure a lot happened, and here is one of them: Day in History: Discovery Jan. 3, 1957: Debut of the Electric Watch, a Space Age Marvel
Topic by Goodhart | last reply
Hi! A few minutes ago, I accidentally unsubscribed an awesome person. The problem is, I don't know who. I was looking at the following page when I apparently clicked on the little cross next to a name. I didn't notice, until the page told me I successfully unsubscribed. Is there a way to know who I unsubscribed?
Topic by emilyvanleemput | last reply
Sit in on a trade show seminar or visit an online forum, and you'll encounter countless debates about the "right" type of mesh to use. The truth is, while there are some guidelines to follow, the best way to determine what's right for your shop is by trial and error. Only problem is, who has the time to experiment? There are literally hundreds of mesh types out there. Trying to choose the best one can seem like an overwhelming task, but by following some general rules of thumb, you can narrow down your mesh choices to a dozen or so. Then testing each kind won't seem so unmanageable. Specs. It may look like the screen on your back door, but screen printing mesh isn't the same kind of material. The biggest difference is that unlike what keeps bugs out of your house, this type of mesh is made from fabric, not wire. For this industry, monofilament polyester is the most frequently used mesh material. When you start shopping for mesh, you'll also need to determine the weave, count, thread diameter and color that's best for your shop. The type of weave is a no-brainer. When researching mesh, you may come upon the terms plain-weave and twill mesh. The difference between the two is how the threads are woven to create the mesh pattern. Make sure you purchase plain-weave mesh instead of twill mesh, which can cause moirÃ© problems, especially in the high mesh counts. Mesh is often referred to by its mesh count â i.e. 120 mesh, 230 mesh etc. â representing the number of threads per inch. The lower the count, the bigger the mesh openings. Low mesh counts are commonly used with specialty inks such as glitter and puff to allow big ink particles to reach the substrate. High mesh counts are mainly used to print fine details and halftones. Printing through high mesh counts also produces a thin layer of ink on the garment, creating a soft hand. Mesh with a count that falls somewhere in the middle is what most screen printers rely on for their basic, everyday print jobs. The last factor you'll need to decide on is thread diameter. Until a few years ago, terms such as S, T and HD were commonly used to refer to thread diameter. Now, however, a more universal method of referring to the diameter number (in microns) helps keep consistency throughout the industry. While there's no standard thread diameter for each mesh count, there's generally a heavy-duty and a light version for each mesh count. The thinner the thread, the better the detail, but the weaker the fabric. The mesh manufacturer or your local distributor will help you weigh the benefits of each and determine what's right for your individual shop. As you shop for mesh, you're sure to come across different colors. Mesh is typically offered in white and yellow, although orange is available from some manufacturers. During exposure, a white mesh will refract the light similar to the way in which a fiber optic cable works. The light travels down and out, affecting edge definition and quality. This isn't as important with lower mesh counts, but when you're doing a lot of fine detail and halftone work, such slight adjustments will show up in the final print. For this reason, many printers stick with white for lower mesh counts, but use yellow or orange for higher mesh counts. Assess Your Need. Everyone has a preferred type, but there are some general guidelines to go by when you're in the market for mesh. Look around your shop and you'll find clues to what type of mesh counts you should be printing with. The three factors to base your decision on are the type of garments you're printing on, your ink type and the kind of frame system that you use on a regular basis. You'll also need to take into account the type of print jobs you typically do. For most screen printers, T-shirts are the order of the day. They can probably get by using a middle-of-the-road mesh count such as a 110 mesh. However, if you print a lot of athletic numbers and use thick ink to withstand the rough treatment jerseys encounter on the field, you'll probably need a coarser mesh count to allow the thicker ink to reach the material. In such cases, it's not necessary to use a high mesh count. On the other hand, if you do a lot of halftone and fine detail work, you'll need a higher mesh count to retain the minute details in the design. Also let your distributor or manufacturer know what type of frame system you use, as some types require sturdier mesh (and higher thread diameters) to withstand repeated use. In general, most screen printers find that a 110 mesh count will work fine for most jobs. The key word here, though, is "most." Don't rely on 110 mesh for each and every single job. Instead, try out different mesh counts with different print jobs, and keep a record of your production results. Note the mesh type, screen tension, type of ink and whether the print job is multicolor, process color, etc. Also note the garment type: Are you printing on a nylon jacket or a cotton T-shirt? Regularly reviewing your records will help you see a pattern, and decide which mesh tends to work best with a particular ink and design combination. You'll be surprised by the varying results between your "everyday" mesh count and one that's a little higher or lower. If you want to experiment with different mesh counts, start with the coarsest mesh and work your way up to the higher numbers, noting how the print looks with each version. Hit the Trail. Most screen printers have an established local distributor that they order supplies from. Others may prefer to order directly from the manufacturer. To find a list of mesh distributors and manufacturers, check out IMPRESSIONS' 2003 Sourcebook. Decoding the Salesspeak. The world of mesh can get a little technical. Here are some key terms to help you navigate the terminology: Low-elongation (LE) mesh â Most monofilament polyester fabrics are low elongation. The term refers to the mesh's ability to retain its tension level. In the past, stretching screens required tensioning the mesh to say, 25 N/cm, letting it relax to a lower tension then repeating the process. Today's low elongation mesh typically only requires one go-around. Monofilament polyester mesh â Some printers who've been around for years still use multifilament polyester mesh. However, the majority of the industry has switched to monofilament. Although it must be abraded for good emulsion adhesion, monofilament mesh tends to stretch, hold tension and print better than multifilament mesh. Plain-weave mesh â Almost all mesh for the textile printing industry is plain weave. The term refers to the method by which the threads are arranged to create the mesh openings. Warp â The threads that run the length of a roll of mesh. Weft â The threads that run the width of a roll of mesh. The Numbers Game. Mesh is typically ordered by the roll, usually in yards. The price depends on the width of the roll (40", 50", 60" wide, etc.), the mesh count and the color. White mesh is not quite as expensive as yellow or orange mesh, because it doesn't go through the dying and rinse processes. Setup Surprises. Be careful how you open the packaging surrounding your new roll of mesh. Avoid using a knife if possible â mesh can be damaged just by being carelessly opened. Once you've opened your new mesh, store it someplace out of the traffic flow. Try hanging it on a wall like a paper towel roll. Getting it up and off the floor can prevent accidental damage. Keeping the roll visible also allows staff to monitor the supply. Don't wait until the last minute to order mesh â you may not be able to get a new supply in time for that next rush job. Care and Feeding. Once you stretch your screens, what can you do to keep the mesh in top shape? For one thing, be careful with your screens. While coarse mesh can withstand more wear and tear, high mesh counts can be easily damaged when moving them around the shop. To extend the life of your mesh, try stretching your screens so that the squeegee stroke runs parallel to the warp. After several print jobs, who can remember what the mesh count is on a particular screen? To help keep confusion to a minimum, consider writing the mesh count number directly on the screens or frame. Or, color code your stock: white for lower mesh counts, yellow for the more detailed work. So while there's no hard rule for what mesh counts to use, knowing what to look for can help you find what's right for your shop. â CW from Internet
Topic by sharefilters
Historians believe the following intricate square written on a Roman wall in England (yes england) was a coded message left by an early Christian while eluding persecution. sator arepo tenet opera rotas
Topic by Pumpkin$ | last reply
Hey, I haven't been as active in instructables as I used to be, but what happened to that "featured" banner that showed if that if your instructable was featured.
Question by dkfa | last reply
A relative took a photo of a grave in Thailand, and my family believes it could be my husband's great Uncle. Who do I contact to get more information about who he was? I have his Private number and which regiment he was in, and a date from the headstone
Question by jackim | last reply
From the article: We investigate the kite bömb - a never before built medieval siege weapön that dropped bómbs from a kite over cities. We build one and test it with startling new insights and success. We investigate ancient bouncing bõmbs that actually skip across water - ... Source of article. I saw this on the Ancient Discoveries. Over the weekend I believe, on TV. The key to stability was a long tail...... Here is a source of information given to me by Kiteman, concerning the Ancient Kite Bómbs (arial attacks before the airplane or balloon).
Topic by Goodhart | last reply
I first had this up as slideshow, but the forums seem to be a better place for it.1st picture (Crossbow V1) This is a picture from the first crossbow i made and if you look at the other crossbow you can see that this one is a predecessor of it.This one however is a bit harder to fire with, since you need to lower your crossbow right after firing, or get smacked in the face by an arrow bouncing back :PIt can get about 80 to 100 feet(if fired well ofcourse) and it could be seen as a light version ofthe other crossbow. It can make a hole in a piece of cardboard (from a box)If instructions are needed, I will post an Instructable.2nd picture(Crossbow V2) already has instructions posted. Actually won a prize with it too :DIt fires 120-150 feet, also depending on wind like most arrows would do. Goes through straight through cardboard.Instructions: https://www.instructables.com/id/Big-Powerful-Knex-Crossbow/3rd picture (Crossbow V3 aka Ballista ) No instructions posted, because there was not enough difference between V2 and V3 and is a bit on the heavy side :PIt has enormous power, but due to having a trigger it didn't fire further then V2.Explodes small plastic boxes, CD's, obliterates red connector of the arrow if fired straight into a wall.4th picture (Crossbow V4) never got finished because it was way too heavy and therefore it was nearly impossible to find a good handle for it. Had a good time dismanteling it....Not much to mention about this one, since it never fired.5th picture (Crossbow V5 "Reaper") is nearly complete and is fully functioning.It uses 4 rubberband strings to do the damage. It also has a new trigger system so that it can hold the full power of the 4 rubberband strings.Its topic is here: https://www.instructables.com/forum/Crossbow-V5-Reaper/Instructions are here: https://www.instructables.com/id/Reaper-Crossbow/6th picture A smaller, more piece efficient crossbow, although not as powerful as the Reaper, it is compact and easier to use.
Topic by Wicky | last reply
When an author retracts an instructable does it automatically remove that instructable from your favorites, and all posts made on that article as well? I had one such favorite that I was SURE was there and when I went back this week it was gone. I also posted questions to the author and I can't seem to find those either. My browser history was lost when I formatted my computer so I was hoping there was a way to track it down on the instructables site. Any hints?
Topic by bhp0528 | last reply
I'm on Chrome (34.0.1847.137) on a Mac (OS X 10.8). Here's what's happening: • Editing a fairly long draft instructable, which I created last weekend. Adding pictures and text to steps. Saving religiously, despite the 3-minute Autosave. • I start noticing that pictures are disappearing from previous steps, when I work on another step and come back. Then, realize that text edits are being removed as well. I re-add the pictures, comments, and text and begin saving even more religiously! • Nnnooooooo! It's still deleting stuff! A lot of work is gone, and I'm pretty distressed. Searched the forums to see if anybody else has reported this. Not really, but I find a tip about the new "History" option (https://www.instructables.com/community/horrible-bug-in-new-editor/). • Click the "History" option while editing a step in the new editor. • An alert appears, telling me to send in a feature request. • Wat Updating my browser now, in case that helps. I would REALLY love to be able to get at the history - I can cobble together previous edits to reconstruct the 'ible, much more easily than rewriting everything. I'll add an update here after restarting/updating the browser. Thank you!
Topic by alexglow | last reply
As a total beginner to the Maker movement who was born in the 70's, I am really excited about people returning to DIY, something that's been out of favor for the last 20 years. I wrote a brief article that gives some historical perspective, but I really want to capture a lot of the recent history of a really incredible movement. What are some of the significant events that shaped the maker movement? http://www.goddardtech.com/blog/modem-%E2%80%98maker%E2%80%99-movement-and-return-diy-part-1
Topic by dkeith-lucas
Each time you save a file, its saved in widows. When you look to open a file you can bring up a list of recently saved files. How do you delete the history of these saved files? Any help is greatly appreciated
Question | last reply
There is much beauty in the science world, although sometimes we have to really look hard, it is there. The history of such beauty is just touched on by NPR's Paging through history's beautiful scienceTake a gander at the star chart below, the actual one has portions that can be rotated....
Topic by Goodhart | last reply
The Detroit Sound Conservancy (@detroitsound and https://www.facebook.com/detroitsoundconservancy) is dedicated to preserving Detroit sounds and telling Detroit stories. To that end we are interested in enhancing and expanding Detroit's archival infrastructure when it comes to sound-related media. While we pursue the creation of our own archival space, we want to encourage our fellow Detroit music lovers in Detroit and around the world to take care of their own archives as well as raise-awareness about the need for archival practices when it comes to music history. So... what recommendations can we make to our allies and friends who might have personal archives and / or materials worth archiving? We are imagining ephemera (flyers, posters), various printed media (articles, newspapers, magazines), sound recordings (vinyl, cassette, eight track, reel-to-reel), musical instruments, and digital files, amongst many other things. What do the Instructables recommend? For $100 we may not be able to create a museum-worthy vault in our home. But surely for $100 we can create a space that would hold up to many everyday threats to our musical treasures. What say you? Thanks @detroitsound
Question by detroitsound | last reply
A team of engineers has used an endoscope to carry out the first visual inspection of Windscale 1 nuclear reactor for more than 50 years. In October 1957, it was the scene of what was the world's worst nuclear accident when it caught fire and released radioactive material into the atmosphere.Just over 50 years ago, British nuclear scientists, under political pressure from a succession of Prime Ministers, had been pushing the reactor to and beyond operating limits in an attempt to develop the UK's own independent H-bomb and achieve an "alliance of equals" with the US.When the fire occurred, the scientists were faced with a choice: let it burn, and contaminate Europe, or dump water on it, and potentially die in a nuclear explosion. They chose the latter, risking their own lives to save people who didn't even know there was a problem.That sounds heroic, but the official report into the incident blamed the scientists for the accident, rather than let the US find out about the H-bomb programme just in the days before signing a treaty to share their existing knowledge with the UK.Windscale (now known as Sellafield - the name was changed after the accident) is now in the long process of closing down. Along with jobs, buildings that marked the dawn of the nuclear age are being slowly demolished and moved ... somewhere else. They don't know where, yet, but it will probably end up remaining on site in deep holes (down in the porous sandstone that carries the local water-table).The original piles were shut down immediately after the accident, and the site's AGR reactor was closed down 27 years ago, but it is only recently that they figured out what to do with them, and they are now being decommissioned as a "UK's demonstration project (meaning; "we've never done this before, we'll work out the bugs in remote Cumbria before we try it on a reactor near a city").As part of the decommissioning work, they now need to see what is left in the ashes of the world's second reactor disaster before working out what to do next.I don't know about you, but I'm not convinced that a paper boilersuit would be enough protection. Maybe that's why the chap on the right looks like he's crossing himself...
Topic by Kiteman | last reply
I just recorded the fastest possibly proven reply on instructables.now, i know, many others have probably done this too, but haven't recorded it!so, i'd like to see some of your shots!try to prove you have commented faster than me *but you can't prove it*updatekillerjackalope has just made the fastest possibly proven comment... *not a reply*update#2i replied to goodhart SUPER FAST!!!!!!!!!
Topic by AnarchistAsian | last reply
A friend asked and i just wanted to know!
Question by patriotsman | last reply
Did anyone watch the Military bone yard episode on the History channel? It is amazing to see how they can repair a vehicle that is in as bad of shape as it was and make it like new again. On the other hand, I could not believe what they do with equipment that is outdated or too much work to rapair.M16 being tossed into grinders Vietnam and WW2 era tanks smelted down into a hunk of metal. Amazing pieces of engineering destroyed along with its history. All because of the idiots in Washington who want to keep this stuff away from the public. The episode pained me so much, that I could not watch the rest of it.
Topic by Sedgewick17 | last reply
This is not a question related to a homework or career assignment. This question is an existential question. Specifically, the thing that I am wondering if it exists, or not, is an easy and automated method for finding the chronological date, e.g. a year, Anno Domini (AD) or Common Era (CE), when a named integrated circuit (IC) was introduced. Preferably this method exists in the form of a free resource on the Web. As an example, the well known 555 timer IC was introduced in the year 1971, and I am reasonably confident that was the year, because the Wikipedia article titled "555 timer IC", https://en.wikipedia.org/wiki/555_timer_IC contains the words: "Introduced in 1971 by American company Signetics, the 555 is still in widespread use..." And I assume that statement is totally true, because if I can't trust the people who edit Wikipedia, I mean, who can I trust? ;-) Unfortunately, Wikipedia does not have a fact-filled article for almost every IC every sold. In contrast, a place like www.alldatasheet.com has data sheets for almost every IC ever sold, but, it turns out, the data sheet does not always reveal the year the IC was introduced. To clarify this further, the thing I really want to exist, would be like a web site, with a name like: www.howoldismyic.com, or www.howoldisthisic.com, or www.icdob.com etc. (Please note that none of those URLs point to actual existing web sites, at the time of this writing.) Moreover, I am fantasizing this web site would contain a form, for to enter the name of the IC to look up, and then after hitting the "Submit" button, it would magically tell me what year that IC was introduced to the world, and maybe also which semiconductor company gave birth to it. As some example input and output, the query NE555 would return: NE555, 1971, Signetics(r) As an additional twist to this fantasy, the query, LM555, would return the same thing, and this magical web page would like, know, that LM555 was a later version of the same IC, except produced by a different manufacturer, namely National(r); i.e LM555 was National's version of the 555 timer . If you have read this far, I congratulate you! And I appreciate your eyeball time! If you are wondering about my motivation for this question, it is just that think the year an IC was introduced would be a very useful metric, like for answering more specific questions, like: The SG3524 and LTC3780 are ICs used for making switchmode power supplies. Which of these ICs is more modern? I.e which IC was introduced latest? It turns out, the answer to this question is: The SG3524 is older (introduced first). The LTC3780 is younger (introduced second). The SG3524 was introduced (I am guessing) in 1977, and that guess is based on some cryptic scribbles in a data sheet for the SG3524, published by Texas Instruments(r). The exact characters were: "SLVS077D – APRIL 1977 – REVISED FEBRUARY 2003" and I am just naively interpreting that blurb to mean the SG3524 was introduced in 1977. Regarding the LTC3780, I think it was introduced some time in the 1990s. Looking at its datasheet, from Linear Technology(r), I could not find an obvious description of what year it was first introduced, but the first page mentions some US Patent numbers, and looking up those patent numbers, gives dates circa the early 1990s. So the LTC3780 is the younger than the SG3524. However to find that answer, I kind of had to do a bunch of reading of datasheets, and US Patent numbers, and that method took a little bit of work. My question: Is there an easier way to find out how old (or young) an IC is? More specifically is there an existing resource on the Web, like a free database, or a IC history site, or something where I can essentially "look up" the year an IC was introduced. By the way there is no absolutely zero urgency attached to this question. So please answer if you feel like it, and don't if you don't. I thank you for reading this. My name is Jack A Lopez, and I approve of this message.
Question by Jack A Lopez | last reply
I'm working on a project for my history class about Ancient Egypt. I'm going to be making a Nile River scene and I need to know how to make miniature papyrus plants and reeds. When I say miniature, i mean like Lego people sized. I need this project in soon, so answer away!
Question by eulaliaaaa! | last reply
Here is a preview of the longest range gun in knex history, the 6 foot!!!!!!!!(the barrel is 6 feet long!!!!!!) Instructable coming soon , or shall I say novel sized building manual, just as soon as I get Mlcad working because of the size of this beast. KillerK and benfoxg eat my dust!!!!!! its still in construction, so subscribe, and stay tuned!
Topic by Knex_Gun_Builder | last reply
So I'm not completely ignorant when it comes to computers but i'm far from a "geek". Wondering if any of out there knows a way to track a computers internet usage outside of viewing the history and without purchasing software. Trying to help out a friend who's daughter is pontentially viewing websites and chats that are not appropriate for a 12 year old. The daughter is well aware of how to delete histories and cookies therefore its not as easier as viewing the history. Is there any way to automatically copy the history to a hidden folder that won't be deleted when her daughter deletes the history? Would really appreciate any help here.
Topic by notreallyageek | last reply
If we look up sonic drills today we usually get some fancy machines driving pipes in the ground, preferably softer ground.But the term includes all types of machines that use sonic vibrations to advance through a media.With the ancient and claimed to have never existed technologies in mind I did some digging...In the food industry vibrating knifes are quite common, same for "air knifes" on softer food.Even in the meat industry they find more and more uses now.Ultrasonic cutting or welding is the same thing and included in "sonic".Same for some experimental sub sonic drilling methods currently being tested.The general idea might be as old as using vibrating equippment to compact stuff, like concrete, bricks and so on.What you can compact by vibration you can also make "fluid" by vibration.Industrial feeder systems utilise this to the extreme by even making light and fine particles like flour move like water without causing any dusting.What all the techniques have in common that a suitable tool or tool head is used and that it is attempted to use the most suitable vibration frequency for the job.Anyone operating an ultrasonic welder knows the pain of finetuning for a new electrode or just new part to be welded.What does that tell us now that makes the understanding easier?Take a bottle of ketchup, preferably one that is still quite full.Turn it upside down and noothing comes out.Shake it a bit and you are either lucky or drowned in red.But hold it at an angle and start tapping it and the red sauce flows out easily.What it true for most newtonian fluids is in some way also true for non-newtonian fluids.Ever mixed corn starch and water to make these funny experiments with it?Hit it hard and it reacts really hard and is not sticky at all.Leave your hand resting on it and in sinks in and sticks to it.Stirring it very slowly is easy, go faster and you get stuck.You can do similar things with by using an external source for vibrations.For example a vibration speaker mounted to a smal cup of the goo.If you place sand on a sloped piece of plastic or sheet metal then at a low angle it will pile up easy and stay.Start vibrating the plate and the sand will start to flow off.Works fine with a vibration source mounted to a piece of steel bar or rod and a bucket of sand too.Trying to press it into the sand requires a lot of force, especially once you are a bit deeper.Let it vibrate properly and it slides rights down.If we can do the simple stuff as well as really complicated stuff in the industry then what about other materials?So far we use vibrations to make things move out of the way, compact things, transport them or to heat them up for welding plus some cutting applications.Considering the variety one might wonder why no one tries it for "difficult" materials.Machined surface can be found throughout ancient history.Finding "machined things" were vibrations was clearly used is a bit harder.The great walls are not a perfect example here as the views differ quite a bit on how they could have been created.But if we leave things melting them or a secret concret like recipe for creating for example granite then vibrations start to make some sense.You find some interesting videos on youtube where people use speakers, wires and rocks to confirm you can actually "machine" them by vibrations.Especially granite has some quite musical properties, big boulders as well as smaller ones produce destinct sounds when you hit them hard.Tests and measurements were made on granite and other hard rocks to check how fast sound travels in them , how it is refeclted and where the sound comes out or affects the surface the most.Lets just say every sample gave different results.Shape, density and dimensions affect not just the resonant frequency but also where and how the sound travels in the rock.What if??We can use a simple speaker, a plate and some rice to see how patterns form under various frequencies.Works with sand or other granules as well.The interesting patterns are the so called harmoncis.Here we see clear and destinct patters, sometimes with extremely fine lines and areas of softly vibrating granules.Some people say these harmonic frequencies have all special meanings and uses.We mainly used them to avoid problems.Imagine your new TV would not have a housing tested to be stable with all frequencies the speakers can produce.All of a sudden your back of the TV might start to rattle ;)Same for car engines.Harmonic vibrations are eliminated wherever possible.Otherwise they could multiply and affect other things in the engine or around it.Simply put it means we have various options to detect and measure vibrations on a surface or in a system.Back in the day every half decent backup generator had a mechanical indicator for the frequency of the supplied electricity.A set of tiny forks with the desired on painted red and several on either side of it.These forks were designed to get into harmonic and therfor quite intense vibrations at their set frequency.If the one for 50Hz looked blurry then all was good ;)The same principle god be applied on a big boulder of granite.Place the "vibration meter" at the desired spot and start moving around the vibration source on the surface until you find a spot that causes maximum response on the meter.Best thing here is that if you then place that surface area onto another peice of fixed in place granite both pieces will start to loose substance if vibrations are applied.The fine sediment forming is then usable as an indicator where to move the vibration source to continue once the effect literally wears off.Is it feasable?Well, if we trust mainstream science then the answer is no.A huge amount of vibration energy would be required for such a hard material, despite ancient proof that says otherwise.Semi industrial test also seemed to confirm the theory as only with very high amplitudes (loudness) and while automatically adjusting for the resonant frequency changes a measurable amount of material was removed.I struggle a bit with that as for the testing tool heads made from hardened steel or carbide were used.And that with little or no regards on how the head and tool itself affects the output.I mean in terms of having the max possible movement happening right t the tool contact surface!There is a huge difference between applying a vibration to a tool and using a system, tool and tool head DESIGNED to work at the desired frequency!Otherwise we wouldn't need a computer to design and test a horn for welding purposes or shade a knife spefically so that the vibration go along the right axis and in the right direction.You not break a hard thing with a very soft thing unless it travels fast enough to become harder as the target!This complicated explanation basically just confirms that if you hit water at a too high speed then it will just break you into pieces instead of offering a soft splashPlease do not jump of bridges or such to confirm this yourself!!If that is really true and science says it is, then how about the other way around?Works fine too, or we wouldn't have pressure washers or water cutters.Now for the part where I hope some really smart people leave helpful comments:If we can cut steel with just a stream of water, then I ask:Isn't for example copper much harder than water?Steel is much harder than copper but water cuts through it.The answer here it simple or complicated, depending on how you want to expain how it works.Comes down to speed and pressure plus the right nozzle shape to prevent a beam expansion.But then water is indeed "harder than steel".Questions:Lets say we would use a copper pipe that in lenght, thickness, hardness and diameter is optimised to transmit a frequency so the pipe end sees the max vibration like a feed horn for ultrasonic welding.Not to hard to calculate these days :)Now imagine said "main frequency" would be optimised for the pipe but also be a harmonic frequency of the rock to be worked on.The pipe end would deform quickly, abrasion does the rest and it fails before even making a decent sratch that is not copper metal on granite.No matter how hard we press nothing good enough will ever happen.BUT: If we would add more hormainc frequencies to feed our pipe we can multiply the amplitude quite easy!Just try with a sound generator from your app store, needs 2 or more channels to be usable.Pick for example 400hZ on one and 800Hz on another, then finetune around these number to hear how the tone changes ;)My theory goes like this:If all "working frequencies" would just harmonics of the resonant frequency of the granite, then they can be tuned so the effect on the pipe end is minimised.The overlaying frequencies however should result in the same effect a water cutter has: The pipe becomes ultra hard.The better the match and the more you have to get it right the harder the pipe will be.Adding now a "drilling frequency" or multiple could be used to drive these harmonics slightly out of phase.Like with the sound generator on your phone we end up with a pulsating sound, or vibration.While the pipe still vibrates at the same "hardening" mix the drilling frequency creates a peak like a jackhammer.Try it by using the heaphone output on a small speaker and placing some light and tiny things into the cone.The will violently jump around during these pulsing tones.For a drilling system the output can be mechanically maximised by utilising a pitchfork design.A head holds the vibration speakers and the tynes are tuned good enough to the frequency of the speakers.Always two would have to operate in sync though as otherwise the pitchfork movement that transfers the sound down the center bar won't work.This head could then be desgined to act as a holder for a quick change of work out pipes that are no longer long enough for tuning.I guesstimate that a well tuned design would result in a copper pipe being able to drill at least 10 to 15cm into solid granite before it wears off too much.And we are talking here about just a few mm to get the thing out of tune!But would dare to desing such a thing just to confirm a theory that no one ever really dared to test? ;)And if friction welding works as good as ultrasonic welding, then what would happen if we try this with the right frequencies and vibrations instead of wasting tons of energy?
Topic by Downunder35m
Bre Pettis (use to make videos fore MAKE, before kipkay took over) has his own TV show, and the pilot will be airing on the History Channel on Friday, September 26th at 9PM! The first episode will be about Nikola Tesla (and if you don't know who he is then you can just leave this forum now!).see full article herehttp://brepettis.com/blog/2008/09/04/history-hacker-history-channel/
Topic by guyfrom7up | last reply
Hello Chaps, I just saw this on one of my Facebook feeds and decided I would share it with you all... click me I'm not a *great photographer* and aside from knowing what I like and what I don't like, I have no vast knowledge of photography etc... ANYWAY I came across this link... and well I think It's fantastic... considdering that over 100 years ago the photographic method used made it possible for us to see these fantastic true(ish) colour images giving us an unique view at Russias cultural heratage... whilst I'm here... may I just remind Americans that it's spelt 'colour' ;) anyway, what do you think? Biggsy
Topic by Biggsy | last reply
I have a project in mind which would utilize a 12VDC 300ma computer fan. I would like to use an old peripheral wall plug style power supply. I have one rated at 12V 500ma which I think would work fine. Problem: How do I determine +/- if I cut the male plug off of the power supply without shorting out my apartment building or spending the weekend in intensive care? The cord is marked along one lead with a gray "dash".
Topic by blackbird03 | last reply
I belong to a Senior group and we are interested in seeing some of this art/craft and learning about duct tape.We are in Oceanside CA.and meet at MiraCosta college. There are about 80-90 people who would attend and we cannot pay since any monies we raise goes to schoolarships for the students. We were wondering if there Is any one in the area to do this? Mary M
Question by magrom | last reply
Where abouts can i get them in bulk for cheap?
Question by sharlston | last reply