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Rebuilding NordicTrack ski machine drive rollers

Many people still buy and use a NordicTrack Ski Machine, although these machines are not as popular as they once were. I have talked to people who say they just plain wore out a ski machine. The part that wears is the one-way clutch inside the drive rollers. NordicTrack makes the one-way clutch sound very mysterious. In reality it is a one-way needle bearing and is available from Amazon or locally from a good bearing shop. The internal diameter of the one-way needle bearing used in my machine (Challenger, similar to a 303) is 5/8 inch. The outer diameter is 7/8 inch. The width of the one-way needle bearing from end to end is 5/8 inch. I originally had hopes of being able to install new one-way needle bearings, myself; but, they together with the bronze sleeve bearings on either side of the one-way needle bearing inside each drive roller are pressed into place. Pressing bearings is not a job for the average home tinkerer but requires a bearing press capable of exerting tons of pressure in a very precise manner. You can often have a local machine shop press the bearings in your machine's drive rollers. Or, you can send them away to Nordic Track Guy and have them rebuilt for about $33 with a one week turnaround. The core of the rollers really does not wear out, but new rollers are available on the Internet from $65 to $95, depending on the vendor. From what I can find, some models used an alternate size. Check to be certain you order the correct rollers, if you choose to replace. One of my drive rollers suddenly began to hiccup. It seemed that the clutch did not always release immediately when I pulled my foot forward. Then I noticed a little mush in the response when I began to bring my foot back on the push stroke. Before you rebuild or replace your rollers, try this: Remove one side of your Ski Machine. See the second photo and check the exploded diagram in your manual. Four nuts and two screws, all plainly visible, need to be removed. Slide the washers and the roller off of the top side. The shaft and flywheel can be wiggled out of the other side without removing anything from that side. Remove the washers and the roller from that side, too. Flush the one-way needle bearing by squirting some penetrating oil, like Liquid Wrench, into the bearing. Work it both ways with your smallest finger. Push a facial tissue into the shaft hole in the roller and sop away the penetrating oil and any metallic dust it lifts. Do this several times. Let the rollers air dry. A little lubrication is good. People who comment on lubrication for one-way needle bearings use Tri-Flo (I am not familiar with it.) or they use a little ATF transmission fluid. You want enough to lubricate, but not so much that the bearings slip. (But, see the comments below where the oil impregnated bronze sleeve bearings are supposed to supply enough lubrication for the needle bearings.) Put the rollers back in place on the shaft. Check to be certain they grab on the rearward stroke and release on the forward stroke. Reassemble the machine. Do not forget the washers between the roller and the side board. My machine works again as it should. The day will likely come when this simple fix does not help, and I will need to rebuild or replace the rollers then. But, for now, my rollers have a new lease on life. What follows is for your information. The first photo is of a portion of the back cover of the manual that came with my machine. It shows a cutaway image of the drive roller. The black printing is mine. Notice the three cylinders inside the drive roller. The outer two are bronze sleeve bearings. The center one looks like a roller bearing, but is a one-way needle bearing. A one-way needle bearing is essentially a roller bearing, but the rollers are able to move forward and backward a little in their cage. There is a wedge shape for the axle of each roller that causes the rollers to bind between the bearing cage and the shaft when the rotation is in one direction, but they are free in the other direction. Here is a description of how they work with graphics. This link is for an Instructable about a number of modifications I made to our NordicTrack ski machine, including how it can be stored vertically in a closet. If you do not have a digital monitor for your skier, or need to replace one, here is an Instructable on how to make your own from a digital bicycle speedometer.  Check NordicParts for any parts you need, also Nordic Fitness Ski Machines. Danny at Nordic Fitness Ski Machines has some very nice new rollers for sale.

Topic by Phil B    |  last reply


Wireless Radar

I am trying to make an arduino based 360 rotating radar system ..the issue is entangling of wires and to resolve this i want the arduino to send data of stepper motor and ultrasonic sensor to processing 3 wireless via hc05 bluetooth module ..what all changes will be required in the arduino sketch and the processing 3 program to make this happen ..if anyone can provide me some link or material on the same ... i am using an already made instructable to make the radar.....i just want to change the radar to a continuous 360 rotating wireless system i am using 28 byj stepper motor with uln2003 driver ,hcsr04 ultrasonic sensor ,hc05 bluetooth module, processing 3 ide for radar output

Question by mukulmagotra98    |  last reply


Are there maker/tech/work shops/spaces in or near the Portland Oregon area ?

With how big being a “maker” is in Oregon, I’ve been unable to locate any workspaces here.

Topic by Sgtcombs    |  last reply


How to build a POP-O-MATIC dice roller

I would love to know how to build a custom pop-o-matic dice roller.

Topic by zombiesatemygoldfish    |  last reply


Tesla coil/Slayer Exciter not working! PLEAAAASSSSEEEE HELLLPPPP! Answered

I have been working on a tesla coil/slayer exciter for a couple of months now, and recently did my first tests, which didn't work, and I couldn't figure out the problem. above is the pictures of the breadboard my circuit is on, the coil itself, and the schematic I based it on. Instructable that I used/followed

Question by Cheesey125    |  last reply


Inexpensive way to grind plastic bottles?

Greetings, I am looking for an inexpensive way to grind individual plastic bottles into particles for easy melting in molds. I tried a blender. It just scrapes it very loudly and burns it. It doesn't break it up. Thanks

Topic by NeuroPulse    |  last reply


What are the benefits to Premium Membership? Also, do redeemable memberships expire?

I recently was rewarded 2 coupons for 3-months of free Premium Membership. What I want to know is what's exceptional about Premium, and if Premium coupons can expire.

Question by Ethan1023    |  last reply


Casio pocket Tv: Tv-1900B info/suggestions on uses?

I just received a casio pocket television model: Tv -1900b, produced somewhere in the late 80-mid 90's(cannot find year) as a gift from my sister, purchased for 2.99 from goodwill, she bought it because I like vintage electronics, and thought it was useable as she was not aware of the difference between dtv and analog, and took the label heading that it received working channels for true, from my research it appears to be functioning but is receiving no signal due to the dtv transition. this is my problem, I am trying to figure out ways around not having an available analog broadcast to pick up, and can not find much info for this tv model online, not even part labels manuals or specs, Im wondering what my options for use or connecting it to another device are.. There is what appears to be an extra headphone sized jack/connector at the top next to the speaker, and a headphone plug does fit into it... but the label for it is long gone, so I do not know if it is an external antenna connection, external composite video in port, external video out port, or a service port of some kind, as it is right next to the rod antenna  screw connection, what exactly is it, and can it be used for an external video/sound input connection?, I see that  on other models before and after this one it can be used as a video/audio input, when utilized with a rca to headphone adapter cord but that does not tell me for sure if mine has that ability. What are my options with this?, I have some technologic know-how, but could not build my own signal transmitter, oscilloscope, built in jack, etc from scratch. is this model capable of easy external connections?, is the extra hole for an antenna input, video input or both?, can a box, dvd or vcr be connected, also is wrapping wire around the antenna and then connecting to the coaxial output on an external device feasible? Iv seen it work on other pocket tv's on the internet but dont know about the true signal quality/effeniency I would be able to make most physical external connection adapters myself, or, are adapters other then the headphone to rca adapters sold to remedy the problem of having a rod antenna and little to no external hook-ups? p.s I am not opposed to having it constantly wired/tethered to a much larger device, as it would be used for a novelty or in a small area where a larger unit would be to big or unweildy, like next to a bed, spot at the table, etc, also I would probably not use it for cctv or similar as I have little to no use for such things the picture included is not of my actual item, but the same model and version, for reference purposes I appreciate any help, as it appears to be functioning it would be a shame to not find a use for .

Topic by spiky84    |  last reply


Reversing Direction of Power Tool

It would be nice to be able to reverse direction of angle grinder, mototool, and similar tools. Sparks may be flying toward ones face in certain positions. The tool also may also tend to kick due to wheel direction. These tools arent made to reverse. How can one change this?  How can one keep the wheel from unscrewing and flying loose once the motor is reversed? 

Topic by Toga_Dan    |  last reply


How to? timed latch release

I want to make a box with seperate compartments with doors that will open to release a dog toy, treat etc. at timed intervals. I don't know how to use a timer to unlatch a door. Ideas? thanks - SpleenMa

Topic by SpleenMa    |  last reply


How do you know that you are imagining things?

Funny question, I know...And usually I could not be bothered less about thinking that something might be a bit odd.I have a permanant job, drive the same car now for over 12 years and live in a crappy rental.Nothing special at all.Most people don't have a landline anymore, I still do for some reason and actually use it when I am home and not a mobile phone.So you might not know anymore when I explain the first weird thing I started to imagine...Ever picked up your phone and got no dial tone?Happens quite often here now....I try a few times and suddenly I got the familiar humm letting me know I can punch in a number.All good then...Then some friends claimed that sometimes I would have a delay from my end and during this delay there is no sound at all, not even the usual static you can hear.Ok, they use mobile phones, no big deal, crap happens.But I thought I might ask my provider for detailed phone records of the past 2 or three billing cycles instead just a summary.Some calls appeared a bit odd with the length of the call.Had a few where I ended on the voice box and hung up but the bill showed several minutes for the call...One local call really stood out though - 3.5 hours.And I know this one can't be right because I people here and actually made the call a quick one...The second weird thing that must be totally unrelated is that an Email account I used for well over 20 years and basically only to receive Emails got blocked by my provider based on claims it is used for spam.Emails to fix it and provide me with a password to log into my account got ignored.So I wasted about $30 for an overseas call to their service department.I explained that my client still receives all advertising Emails from the account provider without any need for a login or password.But all other Emails are kept in my online inbox with no access as my password got changed due the spam claims.As my records would clearly show that during the 20 or so year maybe a handful of Emails were sent from this account the normal procedure for a spam suspicion would have been to follow policies and inform me about it while blocking the OUTGOING part but not the incoming one!Funny enough I got not interrupted once trying to explain the problem but when I ended I got a shell shock.I was informed that my account must have been hacked and used online - however I could not find a single outgoing Email in my online account or Email client.When I asked about this fact and wanted to know details about these Emails I was told they were deleted to protect my account....As a lst attempt I explained that used a 24 digit and quite complex password and highly doubt anyone would have been able to hack it, so I would like my access restored or at least the accumulated incoming Emails forwarded to my verfication account.Apperantly since the spam was stopped by blocking my account there were no new Emails that reached my.Means all those Emails I know my friends sent and those I sent myself to test the account access were just a thing of my imagination.When I asked why my account is still active and provider Emails and notifications still arrive in my inbox on the PC I was told this is not possible as the account is inacative....In case you wonder what the usage for this account was: Pure personal, information and document exchange only.However most of the content in the received Emails relates to what we misleadingly call "free energy".Things like anti gravity propulsion, Scalar drive systems or just plain and really old stuff relating to patents that are almost 100 years old - or older...The last thing that now makes me wonder how active my imagination really is:Ever had the feeling you are being watched?Since about October last year every single parcel from overseas that did not originate in China or Malasia arrive repacked and with an inspection notice from our customs department.And according to some senders I seem to have lost quite a few printed documents in the process...But again, biosecurity is a big thing here, same for trying to figure out how so many drugs make it into the country on the postal or shipping way....However, when my neighbour came over after xmas and asked if I would know the guy in the tiny hatchback that is parked up the street I had to say no, I don't - Why?Appearently the same guy arrives there a few minutes after I get home from work and usually sits there for 2 or 3 hours.Well, not my problem, not my house up there, so why bother.I took a good look at the car and driver though when I went for a quick trip to the shops.I got back home and sure enough the guy was gone, so nothing to worry about.Until I started unloading my shopping and the guy came back, parking in his usual spot.I finnished my unloading, had something to eat and a shower, then took my bins out - and he was still there.Time to have a meet and greet.Don't know about you guys but I find it odd if someone does not react, does not look at you, not even when you knock on the window - just staring out of the windscreen as there was something magical happening in front of the car.And while I kept trying he just drove off...Have not seen the car or driver since anywhere in my street and I guess a car that now constantly parks with a driver in a dead end road with clear view into my road does not count...And yes, I tried the cops and yes the actually came twice until I was told they would not bother anymore.Appearently the poor guy finnishes work now and is waiting for his mate to get back home from work as he does no want drive home and a few minutes later down here.Makes a lot of sense, even if there is never anyone arriving and the guy never leave the car, just drives off once bored enough.It is so good to know that you only imagine things that are not real but just coincidences...However, I would like to know if there other people still using a landline and noticing odd things with it.And how often do you have international shippments inspected by customs and repacked?Ever got your Email account made inaccessible for no reason at all and no chance to ever get access again to it, despite proving your identity and no evidence of any wrongdoing available?If so, did it happen by any chance while you were waiting on some really important documents arriving in this inbox?

Question by Downunder35m  


Sega game gear recap.

I have been repairing Sega game gears for a week now and i seem to be having a consistent problem with the VA1 single ASIC boards. i recap them and none of the work. Ive recapped tons of the twin ASIC boards with no problem i was wondering if anyone could help me figure out why i cant seem to get them working. the power comes on so the power board is good. no sound but the backlight CFL comes on. any help will be greatly appreciated. I am a Blacksmith by trade and happy to trade smithing knowlage for electrical

Question by ScottH384    |  last reply


How do I convert a pair of aeroplane headphones to be used with a normal 3.5mm jack? Answered

The pair of headphones are from QANTAS business class. They have 3 prongs: 2 x 3.5mm and one 2.5mm The two 3.5mm prongs are for left and right sound but the 2.5mm is (i think) for power for the headphones and the noise cancelling ability. I'm not sure how to incorporate the 2.5mm prong into a normal jack or whether it's even possible. I want to use these on an mp3 player or if the power needed is too big then on a laptop. Your help or ideas is appreciated! Cheers, Tal

Question by talco92    |  last reply


Replace LED indicator on charging pack of cordless drill

I have a B & D model RD1440 cordless drill. I recently had new cells put in the battery pack and it works great. My charger is FS14C and it has an LED charging indicator light which no longer lights. I would like to know the correct specifications to replace the LED. Can anyone tell me what is the proper replacement part and the correct way to replace it?

Question by guitarzan214    |  last reply


creating a surface in Invesalius?

Hi there! We want to produce an stl of a heelbone from DICOM files to print and use in an operation. The edible Chocolate Brain was the inspiration to use Invesalius - meshlab I already know so this seemed like a good option. there are, however, limited manuals in english and infos to figure out certain steps in the Program ... like creating the surface for the stl - the mask has already been taken care of and everything else looks right, just this one step isn't yielding the expected result. a link of the document in question to look at - https://www.dropbox.com/s/3oinuz5goz15mws/Fersenbein.inv3 I would appreciate any help a great deal. thank you & snowy regards from Vienna, Eva Tucek

Question by evatucek    |  last reply


how to choose the proper power supply to ESC? Answered

Hello , it's my first time posting here and i hope i have help i have a brushless motor with ESC rated as 30 A max i tried to connect it to a 12V- 125 A power supply but the ESC was burnt i wonder why did this happen ? i was told that the ESC will take the current it needs from the power supply and there are no problem to connect them together can anyone explain what happened to me?

Question by mmokhtar2    |  last reply


'Car FM transmitter to spy bug'

Hello, i am looking for some tips on how to transform an FM mp3 transmitter to a spy bug.. i have that transmitter you plug into the lighter in your car, put an aux cable or an usb in it, and it then trasmits to a set frequency so you can tune in with your radio.. i was wondering would it be possible to just get rid of the jack, and solder a microphone instead? If not, how would I go around that?

Topic by dsirotic    |  last reply



74HC574 VS 74HC595

Can anyone help me understand when you would use one over the other? I am reading the spec sheets and I am not understanding the difference. I am gathering parts for two different projects. One is making an 8X8X8 LED Cube and the other is making a plaque using 8X8 matrix cubes. The plaque will have 11each of 8x8 matrix cubes red and 4each of 8x8 matrix cubes that are RGB. Thank you in advance for your help.

Question by reckerd    |  last reply


Zipfizz Containers

I have a bunch of empty Zipfizz containers. I don't want to toss them in the trash (no plastic recycling in my area). What in the world could I make with them that would be useful?

Topic by jwade19    |  last reply


Separate network for 5 Slaves 1 Master 1 server

I've build a home thermostats system with PIC18F27K42 in each thermostats with LCD, for 5 rooms, 1 master in kitchen and 1 server in the basement, working on a bit-bang i2c. The server only send data to i2c at every seconds as it have a RTC (Chronodot) plus freezer and external temp sensors. The kitchen has a bigger LCD and can send data to the server to send to a dedicated or all thermostats using an ID in the data stream. I have read some docs on the net and bought a ESP32 DevKit V4 with WROOM-32D (changing later for a WROOM-32U external antenna for the downstairs server) and 6 ESP8266 ESP-01S module to include in each thermostat. My goal is to use the wifi instead of the i2c. So I'd like to have some guiding on how to achieve this. Maybe later I may use this wifi to use internet to change some settings in one or all thermostats. But for now do I really need to use the house wifi or can I use a kind of "thermostats wifi", separate from the house one, mostly for heating security. If so, how can I do that, since I'm kind of new to network and wifi. Many thanks to all.

Topic by djdan_23    |  last reply


Post your best jokes here!!!

Whoever posts the best damn joke there is (judged by me) will win a free patch.(not a huge prize, but I hope you still try) Note: The jokes should be appropriate, with no bad language. (8+) The comp has been won! ilpug won with his hilarious panda joke! I hope you all enjoyed each others jokes!

Topic by HMice    |  last reply


Single PCB manufacturing sources

Hey all, So I found a project on here that will fit my needs for issue I have. It has scematicats and a board design. Are there services that make up these items? I really only need one or two made so not sure the big PCB guys will take it on. Any leads appreciated!! Thanks PPVSteve@Gmail.comProject: https://www.instructables.com/id/Simple-manual-control-of-stepper-motors-without-a-/

Topic by SteveW306    |  last reply


How to view the view of a SQ8 camera on your computer?

So I got this SQ8 camera just for fun. Right now I'm wondering if I can show the the camera's view on my laptop? The SQ8 say it can connect to TV and show it's view, can I do the same with my laptop? Here is what I conclude: The USB port of the SQ8 provides 8 wires. However, the cable is split into 2 wire, 1 to the USB head (which have 4 wires) and 1 to the plug for the TV (by the look of things, there is only 2). I have no idea how data is transferred, but here is my guess. The USB head will provide power for the camera to charge and the last 2 wire may have to do something with shutting the connection (If I press the on/off button on the camera, my laptop signal the device has disconnected/reconnected to my laptop).  The 2 wire that transfer the image to the TV is the yellow head, which I have 0 clue how it works cause I haven't learn about it. My question is: is it possible to take this 2 wire to connect and display my camera's view? Here are pictures that I took. In the pics there is the port that the camera has and the 2 end of the cable. 

Question by Shizen    |  last reply


How could I tell if someone installed a phone tap, camera, or voice recorder in my room?

When I leave for work, I sometimes leave my bedroom window open. There is a medium sized gap between the screen about the size of your fist. Is there a way I could tell if someone has tapped my house? Recently my Samsung Flat-Screen has been very snowy and I remember that you could tell is something has been tapped because they interfere with your tv. The house I just moved into also has a wire panel outside my window which you can reach. My room is first floor, please help. I cannot sleep. I also read that you can tell just if you can pick up RF signals coming from the device. Can someone give me a schematic for an RF Signal detector? I can't afford the commercial ones, I once read a stat that if you suddenly wake around 2am or 3am there is %80 chance of someone staring at you. Your body naturally senses this somehow. Well, when I looked at my window, I saw a light then after a few seconds it was gone. I went outside and I heard a couple of cans fall over and my fence my shaking like it was moved. My gate is usually locked but it is a reletively short fence. I haven't slept for days. I can't stand it. I'm going today to buy some black curtains as these cheap plastic blinds aren't cutting it

Question by halo99    |  last reply


i want 2 make a project by using ic 741.. coz it is given by our colg... plz help me...?

Project shud nt b complicated n expensive....

Question by sandyee501    |  last reply


Anyone want to Co-Create the future?

Hi all sydney instructables and indestructables - i just love all this stuff and i am sure some of you are just as passionate. i am running a futures festival and currently in open innovation/open production mode - ie., we all get together and just make a really cool festival. Its called Live Futures 2020: A World of Opportunity. We are creating interaction spaces for the public, particularly young people, futurists, scientists, inventors, researchers, designers, artists, performers, architects, engineers,.......to co-create the future. covering things like nanotech, biotech, health, robotics, education, climate, retrofitting cities to be sustainable, etc... only limited by all our imaginations. If you have something cool to share or just like the idea of co-creating the future join us to create the festival and share the loveat last year's festival we had a young guy who made the coolest electronic musical instruments out of junk and old toys and the crowd loved it. I am sure we now have upcoming electronics whizzes in sydney because of him, i hope tim'll be with us this year too. maybe you have something inspirational too...

Topic by j9j    |  last reply


Increase the speed of an electric motor? Answered

My electric bike, seen here, was built for my senior project. I was limited on motor choice, and had to go with the best I had, an old powerchair motor. After 2 successfull attempts at building an electric bike, I have discovered that it is impossible to go faster that 25 mph with with one of these motors. As you can see on my instructable the bike has 6 speeds, with a top speed of 20mph in first gear. however, when I shift gears, the motor rpm's decrease instead of the speed increasing. I have heard before that it is possible to run an electric motor at higher voltages than it is rated, so I was wondering, if i could add a seperate switch and a "booster battery" of sorts, that as long as I monitered the voltage so as to not let exceed 24 volts, if this would be feasible. My only other option would be to add a second motor in parallel with the first, and on the same drive belt. The first option would be the easiest, if it could work without damaging the motor. Any help would be appreciated. Thanks, iloveairsoftstuff

Question by the mechanical engineer    |  last reply


how to clear up foggy fish tank water using house remedys?

I have a 5 gallon tank and would like to clear it up any suggestions?

Question by pianolover10124353    |  last reply


Micro sstc trouble Answered

I am trying to build the micro sstc by steve ward. My circuit  behaves like there is a short somewhere, but I checked  all the connections. The mosfet isn't connected yet and the 555 timer is getting hot, any ideeas?

Question by theVader75    |  last reply


Food Saver Model V3835 won't open for cleaning?

I was trying to seal a food bag and the vacuum wasn't working so I decided to clean the tray that collects moisture. However after pressing the 2 release buttons the food saver wouldn't open up for cleaning. I have been unable to find what is holding the unit closed. I removed the bottom cover and found the right hold down gear/"hold down" paw not engaged. I re-engaged the paw but still can't open the unit.

Question by glmartin    |  last reply


How do I separate gold from surrounding ores

I live near the site John Marshall discovered gold in 1848.  There is gold dust and particles everywhere!  Problem is that the gold is dust or fine powder form and the gold strongly adheres to it's surrounding ores.  Panning is tedious and not effective.  How can I separate the gold dust/powder from the other minerals?  I have heard using Auger Regis is effective, but cannot find anything on how to use it, purchase it, or make it myself.  Any suggestions/instructions on making or using auger regis; or any other more effective method of extracting the gold from the other minerals is greatly appreciated.

Topic by Ruthless0240    |  last reply


Tesla's earthquake machine - was it just a practical joke?

Nicola tesla, in his early years, was not shy when it came to use science through direct contact.Most of it we would call today playing practical jokes on students and friends alike.His harmonic balancer got the nick name earthquake machine.I won't go into the story how all came together, you can read the story on Wikipedia or other sites to the fullest of your imagination.Howver, I would like to go into some details of this invention.Or better: I will try to explain my view on why this machine might have actually worked close to what the story tells....Studying old paents and other documents is no fun and not always you can reach any valid conclusions from any of it.I mean, if you coud then you wouldn't need a patent for it.Some things however are so good, so special that they never get a patent, the company keeps it as an iternal secret.Same way a brewery won't tell you the exact recipe for the beer they make ;)The harmonic balancer has very little to go with except stories and some comments Tesla scattered here and there.So let's start by some claims Tesla made about this machine:1. It has a free swinging mass.2. The mass is balanced using "air springs".3. It usues very little energy.4. It finds the harmonic frequency of the object attached to automatically.If you think about the above you could say right away it is bogus.But think about the terms and language of the old days ;)Add the fact that Tesla never really gave any direct answers to how his inventions actually work and you see where I am going here.Point 1 and 3 are easy to imagine in many ways.Number 2 on the other hand contradicts itself at a first glance.But, if you place a piston with a good mass and good seal into a cylinder nd close both ends while the piston is in the center....A bit like these to shake emergency torches and flashlights.With that idea in the back of a head one can imagine shock absorbers and more.And a "mass" "swinging" in such a sealed tube would certainly be subject to the "spring" force of the air being compressed in front and the forming low pressure on the other end.The last one however had me stumped for almost two years with me getting nowhere.A mechanical system can't adjust itself to the harmonic frequency of anything....Then I saw a collection of funny videos.One of the clips had about 100 metronomes standing on a board.The board was place on two rollers so it cold move freely from side to side.All the metronomes wre set to about the same timing.But of course you just can't start them all at once or even so they swing in sync.After just a short while though, one by one found a matching partner on the board.Faster ones slowed down, ones totally out of sync seemed to miss a beat here and there.And then it hit me!Hundret swinging masses on a board and the board moves together with them!Once all were in sync and harmony the board moved basically exactly the same way sidewas as the single pendulums above.Number four finally solved :)How though could one try to replicate this impossible invention these days and without knowing any exact details anyway?We know it used one or two electromagnets.These moved the mass back and forth horizontally in the machine.However, it was more formed like a T wih a fat base.Tesla needed a dead simple way of doing with electricity what the metronome does just mechanically.If you have a little mass on a spring and one contact on the spring plus another on a tube that is around the mass - what do you get?No, not the trigger for something really nasty when you pick it up...Right! You get a motion detecting switch.A bit like our gyroscopic sensors do now in our phones....And if you cut the tube lenghtwise you end with two opposing contact to switch two magnets on depending on what side of the tube is hit by the mass (contact) swining on the spring.Try it out with a spring from old pen and a screw inside as a weight - quite sensitive if you get the weight right.Some drawing suggest he height was about the same as the width of the machine.This would suggest the contact was actually hanging upside down, so it could swing in the wider base.A bit of fine and very flexible opper braid with a weight would make a nice pendulum here....Do a little experiment first though ;)Make a sturdy frame or if you have none try a truck. ;)If you place the frame on wheels and a pendulum with just a string and some sinker at the end - what would happen if you move th frame sideways instead of swinging the weight?Inertia keeps the weight in place while the top mount of the string moves away.And if the weight stays in place for just a fraction of a second before starting to move with the frame?Correct! since the angle of the string changes, the ball appeas to move up.Not really by much but enough for an electrical contact to open....We have some ideas now on how those electromagnets might have been triggered by Tesla, what about the mechanics of the moving mass that claimed to have created earthquake like results?Precision is no problem these days, just check these toy kits to build your own Stirling engine or you trusty old Swiss Army Knife.And even a second hand air cyclinder and piston can be modded to act like a free swinging air pump.Only question that really remains would be how to match the mechanical system with the electircal?We have two seemingly independent masses, one to make things move violently, the other to energise the part that make the first mass move - or to be precise to give it a tiny push in the right direction.What does mean you wonder...Let me try to simplify it down a bit.....If you push someone on a swing you can have a very hard time by working against the mass of the person sitting and enjoying the ride.Or you could give the person just a tiny push - right when the swing starts from the highest point to go back.Could that mean it is really as simple to build as Tesla claimed?If the top mass is limited by how far it can swing FREELY before the air pressure works against this movement then we would only have to set the length of the pendulum so the contact happens right at that point on the x-axis of the top mass.Ok, and how would that make anything swing at all?If the top mass is first energised there is nothing to stop or influence the movement, except the "air springs".So it totally overshoots like those metronomes on the board.It swings back and closes the contact on the other side of the movement way early as well.Now the electromagnetic impulse from the second movement actually works against the moving top mass.And this swinging of total non-control continues while whatever the thing is mounted to also starts to move, even if it is just fractional.Over time both swings, from the machine and the object, will get to point where they influence each other in a "positive" way.For Tesla's experiment one would say negative though as it was quite violent in the end.Little by little both swing will get closer to being in sync and with that in resonance.The electromagnetic push however continues....Only that now the top mass of the machine is in sync with the thing it is mounted to.The machine became you standing behind a big swing and trying push someone higher and higher....It is all just a theory though and any minor earthquakes that might register around my area are pure coincidence ;)

Topic by Downunder35m    |  last reply


What to buy?

Hi Guys,I would like to make small wooden boxes, it's my first time would you advice which table with saw should I buy? Greets ChrisPs It should be small and not super expensive.

Topic by ChrisRydzewski    |  last reply


How do I Make a Quiet Book?

I wanted to make a quiet book for my toddlers.

Question by shrikrishnasawant    |  last reply


Rate my art

Hey, I recently drew a portrait of Lady Gaga, and I have then added some colour to it using photoshop. I would love if you guys could give me any critques or positives about it, so that I can improve it! And then I can start working on other drawings I have done too. Thanks :)

Topic by rebeccah18    |  last reply


Our puppy is losing a tooth. Do I pull it?

It's a side tooth and handing on by the skin. Do we pull it or let it fall out? I tried to pull it a bit but it's not giving.?

Question by sekrt8gnt    |  last reply


Please help me identify this Silver signet ring

Found it stashed away in my grandpa's house after he passed, he was a polish immigrant, so it might be from there

Topic by lauracz62    |  last reply


Mariko Kusumoto

I have been trying to create color stripes in the same manner as Mariko Kusumoto. Cotton and silk thread have not worked. I think I need a different tool to apply polyester dye or different thread. The second image is messy but it was to test the strength of the dye on the bubbles. I think my problem now is how to draw the lines using polyester dye before steaming. 

Topic by jeremyzschau    |  last reply


Want to build a automatic opening drawer? Answered

could i use a dvd tray as the actuator if it is under a light enough load? what is the max it could probably open? thanx for any help you can offer

Question by JustinJalapeno    |  last reply


AMEX card not working?

Ive been trying to buy a lab pass for a game Im addicted to. I click the one month option, enter in the info, but it says my credit or debit card is declined! Im using a $50 dollar American Express gift card, but whenever I enter the information it says its declined. So i check on the website, it says everytime I tried (and failed) to use it, it deducts $1. Same for my Visa Gift Card. My mom opened a paypal account for me, but whenever I try it, it says the amount is too great for the card. (its $5.95 ) Does anyone have anyway to fix this?

Topic by wolf555hound    |  last reply


Error

Hi everybody, i need some support in developing this circuit.I'm making a ping pong ball launcher and I just need a servomotor with a switch and 3 dc motor.One should move quite slow and I wanted to use a potentiometer. The other two move together or alone but at the same speed. I want to control the 2 motors and the servo with Arduino. I don't know how much volt I should apply. Should work this way?May anybody give me some hints? Thank you so much.If u may want to change something https://www.tinkercad.com/things/aPDSlGBukDM-epic...I left here my code: #include Servo servo_2;int counter;void setup() { pinMode(8, OUTPUT); pinMode(10, OUTPUT); servo_2.attach(2); }void loop() { digitalWrite(8, HIGH); digitalWrite(10, HIGH); for (counter = 0; counter < 10; ++counter) { servo_2.write(45); delay(3000); servo_2.write(0); delay(3000); } }

Question by vincenzoga    |  last reply


Be Nice Policy

Hi, I have created "Be Nice" memes for everyone to share here on Instructables. I thought it would be a fun way to share your thoughts using the Instructables Robot. You can download the images I created HERE. I will add more as I think of them or through suggestions from YOU. I have also added templates for you to create your own images. If you do create your own and wish to share them, please add them to this community post or to my original Instructable. Thank you and remember to Be Nice. Tater

Topic by Tater Zoid    |  last reply


Cleaning up STL files for 3D printing properly?

Every now and then I find a nice model on Thingiverse or such places that I would like to print.Quite often though these models come with errors.No clue why people upload them for 3D printing if the printing software can't print them....Anyway, there are quite a few online place that fix a model and make it watertight, remove flipped faces and more.Usually with quite good results unless the model is really crappy.What I miss though is a program or online service, preferably free of course, that can actually simplyfy a model to match a printers capabilities.For example a scanned object of just a few cm in size can come with over 100mb in file size with ease.There are programs able to modify a mesh, shrink it or even reduce the triangle count.However those usually still fail to address the problem at hand.Required details go missing and sometimes entire shapes change in important spots.A normal FDM printer comes with a 0.4mm nozzle and is capable of 0.1mm layer hieght with realitve ease.There must be program or service that utilises this properly to create new and in size reduced model.It is just a total pain to use 3 or 4 different programs to modify a simple lithopane just to get some custom text onto the stand.Same for creating multiple print jobs for it as it often results in bad adhesion.What I really would I guess is something where you enter your prefered layer height and max resolution based on nozzle size to get an optimised STL in return.I know your nagging question already: Why bother?1. If you have a STL file of less than 1mb and make some simple modifications with Blender, Meshmixer or whatever, then you can end with a file of way more than 20mb in size and with a complexity that was nowhere in the original."Fixing" a bad file with these apps is easy but again result in massive file sizes or massive loss of detail.2. Mechanics...It really makes no sense at all trying to make your printer create structures finer than 0.2mm - you just won't see it with your naked eye anyway.Especially complex, scanned objects often result in perimeters that enlarged look like someone was holding a running jack hammer while making the perimeter.In return your printer can create quite similar sounds and most importantly the print time goes up for no good reason at all.3. I just prefer simple and clean models.I want to be able to make simple adjustments to a simple object without the need for 32GB of RAM and a server tower to house several CPU's.Is there any such app or service already out there and I just missed it?

Question by Downunder35m  


How can i connect Ardunio uno and rc480 receiverreceiver

Hi if got a ardunio uno board and rc480 receiver with remote and mks stepper controller need to move a gantry up or down using the remote using a nema 23 stepper motor can any one help

Question by Theunisnortje48  


12v battery low voltage disconnect with relay? Answered

Could i make 12v battery low voltage disconnect with relay and resistor? I was thinking if put resistor in series with relay coil i could lower current so relay would barely work on 12v but when it drops to 10v voltage after resistor would be so small that relay would disconnect

Question by Cekpi7    |  last reply


how to extract gold from pcb?

Question by john AR    |  last reply


TR-8 Aftermarket kit, TR-36 "Overkill"

I know this works for cars, so I decided to put an extreme spin on KILLERK recent TR-8. The majority of the body is based of the TR-8, but as you can see I added a little different styling to the handle which is also used to support the heavy turret. I added a bit more of a stock to the original but kept the mechanics the way they were. (can't mess with perfection) The turret itself has a ratchet, similar to the TR-8 which allows the turret to only "wind up" in the correct direction. The turret is also attached the same way as the TR-8 with a socket joint in the grip of the gun. I threw some tactical rails on the sides of the gun to try to hint at capability with attachment but the turret is kind of blocking any attachment you would put there. Overall the TR-36 Overkill feel awesome (heavy) and with that phenomenal power and range you would expect from any turret gun. Tell me if you're interested in an ible' and I'll start working on making one.  Thanks for looking! JonnyBGood

Topic by JonnyBGood    |  last reply


Washing machine motor on an electric vehicle?

Hello, i already asked a question about a car starter as a Motor for my Electric bike project. I got bad news from the answers, so I wanna use a washing machine motor.  My question is, do i need 240V to power it? Or it has like a transformator in the washing machine that makes the voltage lower? I never opened one..

Question by dsirotic    |  last reply


Can I hook a home theater subwoofer to my cars stereo system?

I have a 1999 Jeep Grand Cherokee Limited with an aftermarket Jensen VM9512 in-dash DVD receiver. Can I hook up my subwoofer (Sony SA-W2500) to the receiver and use it successfully? I don't want to buy another sub. What I have to work with is a long enough cable to connect the sub and the receiver and a 12-volt DC - AC inverter. I'm not sure if the 12-volt plug in the back of my Jeep is turned on and off with the ignition or not, but the subwoofer has an automatic on and off mode and the power inverter is just ether on or off. Help? :]

Question by mooseman93    |  last reply