Bolts That Fly Straight

I just made a crossbow from Lego (not much fire power but it works) and I have been firing pencil from it but they hardly go straight. i tried adding cross fins and even an elevator hoping that it would be stable but it isnt working so if anyone has any ideas fire away.

Topic by blckthng   |  last reply


Is there a difference between a 1/4 inch x 20 bolt and 1/4x2 bolt?

I'm trying to make a camera neck strap using parcord and one of these bolts.

Topic by LAPIII   |  last reply


how can we test metal thread with the help of light

Hello everyone pls if some one can help and guide i want to build a device which can scan the threads metal bolt automatically after threading the metal in machine weather the thread is right or wrong i think it is possible with the help of light please if some one can help and guide Thanks in advance

Question by Singh   |  last reply


Which mobile Java browser can read HTML files off my phone?

I have tried Bolt and Opera Mini, both have their own 'mini html' file types - .blt and .obml - but I want to be able to read .html files, so I can have a downloaded version of Wikipedia on my phone. So, basically, which browser can read html files off my phone?

Question by JavaNut13 


6volt powering locking bolts but need diagram to wire limit switches

Hi guys I am need of some advice and help if possible, I will try and explain as clear as I can. I have a lockup which I have modified to use locking bolts on a motor and I have a swipe card reader and pcb which when swiped it fires the output to power the motor (6v) which works perfect for 6 seconds of the locking bolts going in and out. I am looking for a way so when the locking bolts go to the locked position it hits some kind of limit switch and stops there (which I have done in the past) but then I want to be able to swipe my card to open the bolts and when it gets to he open position it hits another limit switch and stays open until I want to swipe and close the locking bolts. I don't want this to be timed I need this to stop on open and closed position but able to operate when either is pressed, Can this be done in anyway?

Topic by sherpin2000   |  last reply


if my sway bar link bushing n bolt broke off would the left suspension (control arms) be lowered?

Im missing the bolt n bushing on the sway bar link the upper n lower control arms are now lowered and the nut on the lower ball joint is riding on the inside of the rim. well sitting on it, im not drivin it would this be the cause? 2001 Mercury mountaineer

Question by TrishMustang   |  last reply


Wiring help

Hi guys I am need of some advice and help if possible, I will try and explain as clear as I can. I have a lockup which I have modified to use locking bolts on a motor and I have a swipe card reader and pcb which when swiped it fires the output to power the motor (6v) which works perfect for 6 seconds of the locking bolts going in and out. I am looking for a way so when the locking bolts go to the locked position it hits some kind of limit switch and stops there (which I have done in the past) but then I want to be able to swipe my card to open the bolts and when it gets to he open position it hits another limit switch and stays open until I want to swipe and close the locking bolts. I don't want this to be timed I need this to stop on open and closed position but able to operate when either is pressed, Can this be done in anyway?

Topic by sherpin2000   |  last reply


How to make solenoid retract when friction applied.

I have a 12V solenoid that was going to be used in a project with a spring loaded door. It was wired into an arduino project and all was going well. That was until I realised that if the bolt had any friction on it that it would not get retracted when power was applied.I wonder therefore whether there is a simple way of making the bolt retract even when friction is being applied?Alternatively, is there a simple mechanism that could be made where friction can be applied to something else that doesn't add friction to the solenoid bolt itself so that when the bolt is retracted the secondary part is free to move and release the sping loaded door.Any help would be appreciated.

Question by mjolnirofthor   |  last reply


How do you make an Inventor assembly with parts that interact? Answered

Currently, I can use constraints to assemble parts, but when they are moved around, they simply go through each other. How can I make the parts push each other around? For example, I'm designing a paintball marker, and it has a body, bolt, trigger assembly, and various pins. How would I make the bolt catch on the trigger when it is moved rearward? How would I make the bolt go forward when the trigger is moved rearward? I'm using AutoDesk Inventor Professional 2012. Also, I have access to most current Autodesk programs if they are required.  

Question by JamesRPatrick   |  last reply


What is the best way to connect 2 pieces of steel together, to make i strong on a Lloyds machine (bolt, weld & etc)?? Answered

I am required to make a 'joint' between to same steel samples.. but the rules are:- The joint will be tested for strength & weighed. Mark awarded in proportional to Load (N) - 100 x mass (g)- All materials and methods are permitted for joint (welding, bolting etc).- Material around hole must NOT be reinforced, but it may ve cut back- All completed joints must fit into the Lloyd machine, using standard attachment (with 8mm diameter pin through the 10mm hole). The holes MUST be 300 +/- 20 mm apart (centre to centre). These holes must be oringal holes - drilling new holes for pin is not permitted.Any help would be So appreciated! Many thanks

Question by SeanD1210mk2   |  last reply


Will you have to create holes in the lift fan, if purchased??

On a hovercraft will I have to create holes in the lift fan, if purchased

Question by  


Can someone help me with this circuit? Answered

I'm working on a fireworks ignitor based off of Bill Gurstelle's design in his book Absinthe and Flamethrowers, and I'm having some trouble. Instead of two switches, mine has three switches.  Like Bill's design, it runs off of eight AA batteries. One end of the battery pack goes to a toggle switch and a keylock switch, and the other goes to a pushbutton. They both end at a bolt. I have two long wires with alligator clips on both ends. Each clip clips to the bolt, then to a piece of nichrome wire which is wrapped around a fuse. In theory, when all of the switches are flipped, the nichrome wire lights the fuse. But this isn't happening. I've tested all of the switches, and they all work. The bolts and the nuts holding them in place both conduct electricity, but no power is arriving at the bolts. All of the components were purchased from Electronic Goldmine, except for the battery pack, which I bought at Radioshack. The ignitor is housed in a wooden (and therefore nonconductive) box. What's wrong?  (Attached is an awful drawing/collage I did of the circuit. If you need a picture of the machine itself, I can take a picture.) Thanks, Noahh

Question by noahh   |  last reply


potato cannon?

I remember seeing a video of a guy shootin nerf footballs out of an air cannon which he reloaded like a bolt action grenade launcher. i cant find it anywhere!!! help plz?

Topic by BigBossXtreme   |  last reply


MOT ( microwave oven transformer) help Answered

OK, i just pulled this huge transformer out of a microwave today and was just wondering how on earth to hook it up. Pictures below. so please help. And sorry about the pictures being sideways. The bolts you see are on the bottom.

Question by budhaztm   |  last reply


Lost the "How to Build a Robot/Anything in a Week" write-up in Instructionable - ?

I'll lost the location of the excellant write up on physical robot chassis construction techniques. It included examples of making truss type chassis construction and the bolting (with slots) of flat planel of aluminum together to assemble a robot chassis.

Question by Hegemann   |  last reply


What are the specs (maximum file size, number of pixels, etc.) for making your own digital patches to send people? Answered

(I'm sure this info is here on the site somewhere, but several searches haven't turned anything up.) Thanks.

Question by Gorfram   |  last reply


How can I measure pressures/strain up to 5000kgf? Answered

I desire a device to measure a weight up to 5000kg. I don't know if this is termed a strain gauge or a pressure plate. my requirement is that the pressure plate itself be at least as small as a washer for a 10mm bolt. I need the device to record the maximum force, as the force is variable over time.

Question by Phil11   |  last reply


How do you "unjoin" a group or community?

I recently joined the homemade firearms community and realized that the group is focused on highly illegal NFA weapon construction and i want no part of it.   I thought this would be a group of mature law abiding amateur gunsmiths building legal single shot, bolt guns or semi-auto rifles and handguns but based on the few posts I read, this is not the case.

Question by GDC   |  last reply


Casting Resin issue?

I'm trying to cast some resin claws for a halloween/convention costume I'm trying to make ( it isn't a Wolverine one .. more a VERY twisted, evil, and blood thirsty Mad Hatter character ) and running into a bit of trouble. I'm following the 5 drops of hardener per 1 oz of resin that is stated on the resin can's instructions. It also says it's supposed to set hard enough to support objects at 40 minutes. I mixed a 2oz batch of resin ( 10 drops of hardener ) and poured it into a rubber latex lined plaster mold that I had sprayed with mold release. I put a bolt down partly into the resin so I can later attach a wire to it and left it alone for about an hour to an hour and a half. I came back to check on it and the bolt was still able to be moved/removed with NO resistance. I figured the mix was bad and threw it out, but noticed it was the consistancy of slime. Did I mess it up and not wait long enough, or did I not add enough hardener or what ? Any suggestions would be great!

Question by Myrr   |  last reply


Van Helsing Crossbow

I just finished watching van helsing for the umpteenth time and the crossbow that carl gives him is one of the only cool things in the movie, apparantly its steam driven works like a machine gun and uses magazines of crossbow bolts. So my question is, is it possible to make something of the sort using technology from that time? Unfortuately I havent had any ideas on its useage or working as yet.

Topic by blckthng   |  last reply


installing a DVD console in a 06 Malibu Maxx?

I have an OEM DVD RSE (Rear Seat Entertainment) console. It is for a 2006 Chevy Malibu Maxx LTZ. The console I have in my car is without the DVD component. I see 4 holes to bolt it into the center. As I will have to remove the one in my car and replace it with the new GM part, will I have to take the seats out? Anything special I should do first?

Question by  


Idea for flip cam "real" steady cam. How about this for a "real" steady cam. The flip cam is tiny in mass and volume.?

Why not use the head motor from a VHS recorder.If the rotational inertia is not enough, perhaps some bolts around the perimeter of the head, the assembly would have some type of handle attached to the camera (bicycle hand grip) the vhs motor attached to the bottom of the handle, battery pack to attach to belt?

Question by naic98   |  last reply


how to make a ride out of scarp wood?

Oh and ment by scarp wood by wood thats like left over and turn it to a thirl ride by the the use par say drills a few nuts and bolts a hammer and some nails the reason why i ask because i do like to play around wih a few and tend to make stuff like a rocket which got way out of my hands a blasted half way to orbit and crash landed the half way to orbit thing is just a saying.

Question by neivadan   |  last reply


repair to a worn out dewalt dw613---C type 1 router? Answered

I need help to my router it started to make a terrible noise,so turn it off and check the brushes and they are fine.Then I try turning the router cutter on the machine by hand it does not turn freely it seems to be catching some thing in the machine.How do you take the main body off the router,I removed 4 long bolts it swivels but does not come of the machine I need to see whats at fault can anyone help ??????

Question by ander19   |  last reply


P.M. D.C. Motor for Treadmill

Hi I am working on an Image 15.0 R Treadmill. As soon as you start it , it shuts down as if the circuit has been interrupted. I unhooked the drive belt so that there was no resistance to it and it does the same still. The speed sensor seems to be working okay so I pulled the controller (board) and tried re-flowing it. as I flip the treadmills switch on not starting the treadmill-just turning the power on the motor runs for about 3 seconds. Because the cover is off while I am working on it I can see that during that 3 second window the motor has a spark (bolt) from one of the bolts to the post (I think stater) the one that if the motor were disassembled the part spinning inside the copper wind. I don't remember what it's called (armature?) Anyway this arching does not re-occur unless I completely unhook the board once more and re-assemble. After re-flow the motor still just begins to load (start) bumps about 1/2 a rotation and stops. I read an article here that Iceng had commented about bringing his P.M. D.C. Motor model # c335483304 back to life......it is the exact motor....my girlfriend has been on me about fixing her treadmill so here I am. Anything would be of great interest and help to me. Thanks a million in advance. Troy

Topic by ill build u one   |  last reply


Head unit not charging iPad

Hey All, In my car i have an after market HU with a usb port that my iPad 3/ iPhone 4s / iPods can connect to. However when my iPad is connected to it is unable to charge. The charging indicator in the iPad has the little lightning bolt going through it, indicating that it is indeed charging however the iPad looses about 7% of its battery every hour. Does anyone have any suggestions on how i can get my iPad to charge through my HU? Cheers  

Topic by wrignj08   |  last reply


Stirling AC, someone tell me why it wouldnt work.

Take a split type airconitioner unit (with heat exchanger / motor etc outside the house) remember that heat pumps have COPs >1 so they remove more energy than you put in. Now take a reasonably efficient stirling engine and bolt it onto the external heat exchanger so there is a gradient between the hot heat exchanger and the warm air outside and use it to pump the refrigerant around the system. Surely a heat-pump stirling engine combo can be made efficiently enough to effectively run itself once it has been started up, maybe with a few watts of electric to run some fans.

Topic by pyper   |  last reply


Milling machine cheep from Harbor freight

Ever wanted a small milling machine to mill aluminum ? Heres a cheep way to do it. It's not real accurate but it gets the job done. and for under $ 160.00. all the parts come from Harbor Freight (Drill press on sale 70.00) (roto zipp bit 2.99) ( 8 inch crosss vice 39.00) some bolts and thats it ! it's slow so take your time and the vice is a little rought but it gets the job done. Run the drill press at the highest speed on aluminim slower on plastic and use small cuts , don't try to hog out the part it will break the bit. have fun !! There you have it.

Topic by motorcoach1   |  last reply


Will a glued acrylic structure hold for a 3d printer ?

Hi,  I'm designing a delta style 3d printer from scratch while trying to use only laser cut acrylic sheets and aluminium extrusions. The entire design is based on the T Bolt construction idea. But there are a few parts that simply need to be glued together. I'm trying to avoid using such joints in load bearing areas but there are a few areas where this is becoming difficult such as the carriage. I'd like to know if i can safely glue the laser cut parts together with out the entire thing falling apart and if yes what kind of glue should I look for? Blckthng

Question by blckthng   |  last reply


I'm making an air cannon and I'm trying to make it automatic. How do I make the timing circuit?

I don't have all the details worked out but it should look like: http://i123.photobucket.com/albums/o290/Strid3r34/EggCannon.pngI just need to know how to make a timing circuit so that the bolt reloads (the servo should retract then detract), and then the solenoid valve is switched on for a split second (so as not to waste the air) and then reloaded again. I need it do this as long as the trigger is held down. I have no idea how to make this circuit, and I'm totally new to this so please explain in detail. pictures would help a lot.?

Question by strid3r   |  last reply


How can I disassemble a dc brushless fan without breaking it? Answered

I've got a couple old fans from computer power supplies. I'm removing the plastic fan to get at the motor. The plastic casings have different designs, but the core seems to be the same. I remove the sticker and pop off this little plastic cover. I'm expecting to see some sort of bolt or screw holding the pieces together, but instead there looks to be some sort of metal rod with a white o-ring. I'm assuming that's the sleeve bearing, but I have no idea how to remove the plastic fan; other then pry it off or dremel. Any ideas?

Question by Vorenus   |  last reply


How to mount a wheel to a weed eater engine (direct drive) when building an r/c car?

I want to use a weed eater engine to make a fast r/c car. I have already stripped the engine down to it's basic components (removed all the plastic leaving only the bare engine) to make it easier to mount to a to the vehicle. I pulled an 8" pneumatic wheel off of a Razor electric scooter which i plan to somehow mount to the clutch system of the engine.The idea is to have a direct drive system to cut down on the complexity of a chain drive (I have the chain drive off of the electric scooter). To do this I'm thinking of bolting the wheel (which has 3 treads that previously mounted the sprocket to the wheel) directly to the bell of the clutch (the part that the clutch engages at a certain rpm and connects to the engine to the driveshaft of the weed eater). Is this a good idea or is the bell not strong enough to bolt a wheel to? For those of you who don't know what the bell is that I am referring to: http://i1.ytimg.com/vi/6FcFkbxhAXU/hqdefault.jpg Once I have the wheel mounted (it will have a single rear wheel), I will use the front end of a spare r/c car for the steering and the drive motor to pull the throttle cable on the engine. This will probably be mounted to a plywood base. Ideally, the best option would be to have servos hooked up to an Arduino controller to control the steering and throttle, but a WiFi Arduino ($80) (could I substitute it for a Raspberry Pi?) + 2 servos ($30) is outside of my price range. What do you guys think of my design? Any suggestions?

Question by epicnoobpwn   |  last reply


DIY Ipod Amp Kits

I have all put together all the parts to make your own iPod Amp as seen in ReadyMade magazine issue 23 and Instructables.The kit includes:Velleman Amp kitSpeakerArmy Surplus Case1/8" Stereo JackWireLEDResistorNuts and Bolts to secure speakerPower Switch6AA Battery Holder w/ snap connectorThe price is $45 + $5 for shipping. You can follow the step by step instructions at: https://www.instructables.com/id/Simple-iPod-Amp/Thanks,-JoeYou must pay with paypal and I will only ship to the US, sorry I just end up losing money any other way.

Topic by joe   |  last reply


How to use a capacitive touch switch with an mp3 module

I have an mp3 / bluetooth module, which I currently use with a set of buttons extended out in parallel from the board ( https://www.instructables.com/id/Bolts-As-Bottons-...). I'd like to make another system using a similar mp3 module and a set of capacitive touch switches ( https://www.amazon.co.uk/SODIAL-TTP223-Capacitive-... )in the original, I just soldered a lead either side of the momentary switches on the board, however the capacitive switches have two power connections, (vcc and ground) and a single output connection so I cant connect them in the same way, how can I connect these switches to be the controls for the mp3 module please?

Question by oragamiunicorn 


How to power a strong Electromagnet?

I want to make a fairly strong electromagnet for general use but I also have a task in mind. I live in an apartment building near some students and someone egged my window. The egg dried in and now I can't reach it to clean it. I've see magnetic window cleaners before but they are cheap, weak and not up to task so I'd like to make an electromagnet to help with the scrubbing action. The windows are double glazed and the neodymium magnets I have are not strong enough. The only electromagnets I've ever made were the basic science experiment type, coiled copper around bolt with a battery to power. For this I assume I'll need a large battery or would it be mains powered? Any suggestions?

Question by nodnodwinkwink   |  last reply


xbx 360 RROD? have tried a hot air gun reflow + x-clamp replacement?

Ok so i bought some xbox's with the intention of fixing and selling them. they all have 3 red rings. i have tried using a hot air gun to reflow the board but it hasn't worked. i also added in bolts and plastic/ metal washers to all of them but still nothing. one of them turns on then beeps and goes to 3 red lights. another one goes on for about 20 seconds (with no picture or sound) then goes to 3 red lights. the other one just has 3 red lights. i was wondering what else i can do? thanks

Question by MANIAC 


Mini Bike Chain Adjustment Trouble? Answered

I recently bought a bunch of pocket bikes all in good shape but all had some sort of problem.  I took the best parts off of them and made one extremely nice bike.  The one problem I am having with it is that the chain likes to come off.  There is a bolt connected to the back axle that tights and loosens and slcks or tensions the chain.  How do I find the "butter zone" where it isn't too loose to come off, and it is too tight to come off?  The two sprockets are lined up really well, but they are a little off.  Would it be possible that that was the problem?  When I say a little I mean like so small its less then 2-3 mm from drive sprocket to driven sprocket.

Question by Electric Spectre1   |  last reply


Project ideas for a MacGyver game?

My cousin is joining the army this summer.  He's going to be a bomb defuser! We're going to give him a big send-off before he goes but we want to send him off with a little training. Another of my cousins is going to weld together a "bomb" shell and we are going to try to make it a puzzle that he has to solve / defuse using nothing but his MacGyver/ MacGruber  bomb disposal kit that we'll give him. He'll have things like matchsticks, tube socks, duct tape, etc.... and he'll have to use that stuff to defuse the "bomb" The most obvious thing I want to build into this thing is a countdown timer.  That's probably what he'll find when he gets all the way into the center. I want it to do two things:  Not activate until a pressure or momentary switch is RELEASED (he'll open a little door or something which will start the clock ticking) and I want the timer to stop when he cuts the correct wire.   Obviously it's just a toy, so it doesn't need to be particularly fancy or functional.  I'm not hunting for diagrams that could be used to build a  real detonation timer.  In fact the cheaper and cheesier the better, especially since my skills in this area are pretty limited. I know how to build an electronics project according to specifications, but I don't know much about designing circuits.  Does anyone know of an instructable out there that fits my description? Or at least gets close?   Have any other awesome ideas for stuff we should include in our MacGruber puzzle?  My cousin has an insidious idea for bolting it shut with a bolt that is threaded half clockwise and half counterclockwise.  you can get the nut halfway off but then it won't turn anymore unless you start turning it the opposite direction, which nobody ever figures out.

Question by UselessTrivia   |  last reply


Auto body help

I need some help here and I hope that there is someone that can answer this question. I have a 2003 Toyota Tacoma and I want to add some bigger fender flairs on the truck, I want to use what are called pop rivet nuts. The pop rivet nuts are inserted just like a pop rivet but it has a nut on the back of it so that you can use a small bolt. The screws that came with the fender flairs are called self tapping screws and they seem to wallow out after time. I need to know what the thickness of a typical fender is so that I can order the right pop rivet nuts. The pop rivet nuts only come in sizes for gauge metal. Does anyone know what gauge a finder is so that I can order the right pop rivet nuts. Thanks for any input.

Topic by fishhunter1957   |  last reply


Variable Speed on a DC motor

Hi everyone, Does anyone have any suggestions on how I can slow down the roatational speed of a 14.4V DC motor? Its come out of a cordless drill and I have another project to put it to use but it rotates too fast at the moment. I have 2 options: 1) Use a variable resistor to slow down the speed 2) Use a gearing system In an ideal world I would prefer to use the variable resistor, as then I could change the speed of the motor quickly and effortlessly. Mechanical circuits are not my best skill and Ive already burnt out a cheap potentiometer (presumably too much current?) so I need to think more inteligently about what the design should be rather than just bolting components on the side of it. If anyone has any ideas please feel free, im open to all suggestions at the moment. Thanks Mat.

Topic by mathewjenkinson   |  last reply


Strange Electromagnet Observation

Hey everyone. I'm fairly new to the hobby electronics world, and today I decided I'd build an electromagnet. I wound my coil around a steel bolt, and I used 3 Duracell AA (1.5V) batteries for a power supply. When I turned on the switch, I found that my beautifully wound coil took a little bit of prying to get it off of the metal base I was working on. I thought "Let's try 9 volts!" So I grabbed a Rayovac 9V battery that I had around and hooked that up in place of the 4.4V (measured) bank. The Rayovac measured to be ~9V. The electromagnet was noticeably weaker. When I tested my magnet with just one of my 1.5V batteries, it felt like it had similar strength to the 9V battery.  Can anyone explain what might be going on? Short of that, could someone tell me how to measure the current coming off of each power source?

Topic by TheMike25   |  last reply


I need advice on selecting a heatsink for a high-power LED driver circuit.

Can someone help me out regarding the proper heatsink to use for Q2 on step six of this instructable- https://www.instructables.com/id/Circuits-for-using-High-Power-LED-s/ My LED (part number 475-2581-1-ND on digikey) draws 1.4A with a forward voltage of 2.5V. I am using a wall-wart that gives me about 10V. My LED runs smoothly, but the two heatsinks I've tried using with Q2 get *very* hot to the touch. I bolted both of them on using thermal compound. Both are TO-220 "U" shaped. One is about 2cm tall by 1cm wide (about the height and width of Q2). The other is about 3cm tall by 2.5cm wide. How hot is too hot for a heatsink? Would a different shape be better? Thank you so much

Question by erikp   |  last reply


Making a lightstand from a mono pod?

Hello all,  This is my first time posting on instructables.  I've found and used so many great photogrpahy ideas on here I figured someone might be able to help me out with a little problem I'm trying to solve.   I got 5 of these:  http://www.newegg.com/Product/Product.aspx?SID=u965992t2606681f30fp45859c0s701&AID;=10440897&PID;=1225267&nm;_mc=AFC-C8Junction&cm;_mmc=AFC-C8Junction-_-cables-_-na-_-na&Item;=N82E16830997069 I got all 5 of them for $5 total because of a $30 giftcard I had.  They were on sale for $7 each.   I'm trying to figure a way I can use these as lightstands for my speedlights.  I've had the thought of building an X type base out of wood with a bolt coming up through the base of the monopod but I was thinking of trying to find somethign that would be a bit more portable an X I could fold down somehow but that would still support the monopod.   I'd be grateful for any ideas?

Topic by bentlax33   |  last reply


Need Data Sheet for old diode laser. RCA SG2001

I have been digging though my assortment of electronic components, stuff that has gathered dust for years.  One item I came across still new in the original package is a laser diode.  RCA # SG 2001.  I have tried searching internet with out much luck other than a PDF about how to drive the diode.  ( short pulses high current ) I see the same part number referenced for other products.  I did find it listed but there is no data showing that I can find.  Yea...it is over 30 years old !  No reason not to know what it is or what it could be used for, perhaps for the pocket engraver? Would much appreciate any information anyone may have about this chip.  I believe it is fairly high power IR diode.   It is stud mount with a single lead exiting the center of the stud bolt.  A bit less than 1/4" dia case.

Topic by stuffdone   |  last reply


Magnetic accelerator coil Answered

Im going to try to keep this short. So a friend and I are both sophomores at our highschool and we are both in chemistry (which is a higher level science) and i built a coilgun for last years project and attempted to build a PWM driven one this year. My friend and I want to build a rather large coilgun using either 10 microwave oven caps or close to 40 or 50 caps from computer power supplies. What i need help on is whether we should use the microwave caps which are high voltage but low capacitance or the power supply caps which are 200 volts and around 500 micro farads. I also need help on what wire to use for my coil and how many turns for the coil. i would like help with a coil for each cap size. We are planning on using either a 3millimeter by 5 centimeter long steel rod or a quarter inch bolt. our goal is to at least shoot it through the wall of the physics classroom and maybe through the door of a car. anything helps. Thank you

Question by budhaztm   |  last reply



Let us assemble power distribution switches at home together.

I am an electronic engineer in the field of power distribution switches. In recent days, I am prepared to make a project for power distribution switches at home together.  The project begins now: Home decoration, the concern of hydropower indispensable. The laying of the home circuit is a crucial link, the home distribution box installation involves the safety of home appliances. Therefore, I specifically summarise the home distribution box installation knowledge, as well as home distribution box wiring diagram to make the relevant finishing, for everyone to take precautions, the home distribution box has a clear understanding. Home distribution switch installation points 1, Household distribution switch sub-metal shell and plastic shell two, there are two kinds of mounted and concealed, the box must be intact. 2, The household distribution switch of the cabinet wiring assembly should be set up to zero line, to protect the ground wire, phase line, and to be intact, with good insulation. 3, The installation of air switch seat should be clean and there is enough space, should be installed in the dry, ventilated parts, and no obstruction, easy to use. Never install the distribution box in the box to prevent fire. 4, The household distribution switch should not be installed too high, the general installation of the elevation of 1.8 meters, in order to operate; into the distribution switch of the electric tube must be fixed with a lock nut. 5, If the household distribution switch to be open, the edge of the hole to be smooth, smooth, distribution box buried in the wall should be vertical, horizontal, edge left 5 to 6 mm gap, distribution box wiring Should be rules, neat, the terminal screws must be tightened. 6, The loop into the line must be sufficient length, no joints, after installation marked the name of the use of the circuit, the installation of household distribution box to be completed after the removal of the distribution box residue. How to assemble power distribution switches at home ? 1, The installation of electrical box, distribution box installed on the wall, should be used bolts (expansion bolts) fixed, bolt length is generally buried depth (75 ~ 150mm), the thickness of the box floor, nuts and washers Of the sum of the thickness, plus about 5mm of the "margin". For smaller distribution boxes, it is also possible to embed a good brick at the installation site (in the form of a distribution box or a panel mounting hole) and then use wood screws to secure the distribution box or power distribution board. 2, Dark assembly distribution box, distribution box embedded in the wall installation, in the wall when the hole should be reserved than the length and width of the distribution box about 20mm, the depth of the distribution of the thickness of the distribution box with the wall Plaster thickness. In the masonry distribution box, the box and the wall filled with concrete can be fixed to the box live 3, The distribution box should be installed firmly, horizontal and vertical, vertical deviation should not be greater than 3mm; concealed, the distribution box should be around the gap, the edge of the panel should be close to the wall, the box and the building, Part should be coated with anti-corrosion paint. 4, The distribution box installed in the spiral fuse, the power cord should be connected to the middle of the terminal contact, the load line should be connected to the threaded terminal. In this way, in the loading and unloading fuse will not be electric shock. Porcelain plug-in fuses should be mounted vertically. 5, The distribution box of AC, DC or different voltage levels of power, should have a clear sign. Lighting line, should be set to zero line (N line) and protect the zero line (PE line) bus, zero line and protection of the zero line should be connected to the bus, not twisted, should be numbered. 6, The wire leads to the panel, the panel line hole should be smooth without burrs, metal panels should be installed insulation protective cover. Metal shell distribution box shell must be reliable grounding (then zero). Ps: Excuse me if I was wrong in words or expressions as I am a green hand in the field of power distribution switches. I need continual learnings. What is your idea ? Do you agree with my ideas ? Any of your ideas would be highly appreciated. May someone would like to help ? thanks in advance.

Topic by maryzhu   |  last reply


Help with building a tesla coil? Answered

I want to build a tesla coil, but I want to verify with the instructables community that it won't blow up, burn down my house, turn into skynet, etc. Here's my plaaaauuuuuuhn: For the transformer, I'll be using an old negative ion generator thing that takes in 120VAC and outputs 7.5kv(pic). For the primary, I'll use old speaker wire in  a cone shape (possibly using acrylic). For the secondary, I'll use 32- gauge magnet wire (pic). And for the spark gap, I'll use two bolts in a box, possibly with a computer fan cooling it. And for the capacitors, I'll just use an array of Leyden jars. My questions: 1. What diameter should the coil form be? I have some random white tubing which has an OD of 1/2 inches, 1/2 PVC piping (which actually has an OD of 7/8 inches), and 3/4 inch PVC piping. And is there a better alternative to these? 2. Should I use chokes on the input/output of my transformer? For those, I think I'll just wrap a bunch of wire around a pen. 3. Should I varnish it? 4. How powerful will the EM be from this thing? Exploding computers aren't that good. If I have made any errrors, please tell me.

Question by Shagglepuff   |  last reply


Calling all small engines mechanics!

I have a problematic Ariens YT12 tractor that I have been meddling around with all summer trying to make run perfectly. If I make a video and post it on youtube, to show what it's been doing lately, can someone help me out??!?? I got kinda drunk one weekend and I think I revved the sh*t out of it, the weird things is, I can cut grass with it at full throttle for 2 hours but as soon as I go to rev the engine higher with my modified gas pedal or when I'm adjusting the carb, it just revs up then it starts to sputter and it wants to stall. It's really weird, and although I think I could use a new crankcase gasket, I know the engine is not blown, I'm wondering if maybe I've melted something in the carb, considering how close the carb is to the exhaust pipe on this machine, and the fact that it's a hot running machine (I remember shutting it off one night when it was dark after cutting grass for two hours, the bolts the hold the exhaust on the engine were glowing bright orange.) Anyways I won't bother explaining too much of it, but I'm wondering what I did to my baby and I know a video would probably clarify things a lot better. Something needs to be replaced on it, I know for a fact, it's just a matter of what. I figure even a new carb kit to replace the gaskets and the needle and pin would probably help oodles.

Topic by Punkguyta   |  last reply


How can I make a water level indicator panel for an RV fresh water tank?

I'm rehabbing an RV.    It has a 100 gallon fresh water tank made out of plastic (polyethylene). The tank has four built in sensors on the side of it, 0%, 25%, 50%, 75%, I assume these sensors are just a bolt sticking through the side into the water. How can I make a simple indicator panel which will light up an LED for 25%, 50%, and 75%? I doubt I'd just be able to use the electrical conductivity between the 0% sensor and the other three, as the electrical resistance would be too high to send any usable connection through the water, am I correct? But maybe something based on capacitance?   Anyone know how to build something like that?   My skills are too rusty to think that through. Maybe I could cannibalize the sensor out of one of those touch sensitive table lamps and use it as the basis for my indicator panel? I'd prefer not to use an arduino or pi for this, I need something incredibly simple and robust.   I realize those would do the job but I need the quick and dirty solution. Thanks in advance for your help. EDIT:   Here is a webpage that talks in depth about the standard tank monitors and how to upgrade it with an Arduino.   Unfortunately, this seems incredibly over engineered for this task and I don't have the liberty of spending the time to do this, as I am working with a tight deadline.  But it does discuss the resistor network which was originally used with the sensors on the tank.   Since the original display panel on mine was too damaged to save, I thought it wouldn't be too hard to rig up something simple to replace it.  http://www.thorforums.com/forums/f27/diy-capacitive-tank-sensor-1177-2.html

Question by JimTheSoundman   |  last reply