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DIY CNC Machine: Linear Rails + TinyG Part 1! Widget40

we've got a tiny-g cnc controller we've got some pneumatic cylinders we've got some NEMA 23 stepper motors and we've got some awesome hardware like these ball screws folks let's build a bigger and better DIY CNC machine welcome to another episode of NYC CNC it was amazing to see the success and interest in the DIY CNC machine that we built just a few months ago and the emphasis there was on just how inexpensive and just how easy it is but with the Arduino with the G shield and some really inexpensive hardware I love that machine I think the only one mistake I made which we've discussed in the comments on that video was it would have been a little bit more rigid we were using this type of rail and and barring if I'd used two of these and that would have given it some more stability but nevertheless I think it proved the point that what a phenomenal fun project and easy to get into this really totally different we're going to use the tiny G shield which is more powerful more responsive we're going to have hopefully the limit switches and just more control because I want this machine I want this a machine to cook and we're going to use NEMA 23 steppers hopefully just bigger able to deliver again more speed but the big difference is really going to be the hardware and it's not cheap just period there's it's not cheap I think one of the things I'm hoping that we'll see change in the next [ __ ] in five years or sooner is a more access at our level whatever you want to call that though your DIY or home user to this kind of stuff because right now buying linear rails bind the ball screws and all the hardware for it I think is overwhelming there's too many choices it's not clear what's what and it's expensive you know these all the links are going to be in the video description below but you're looking at you know things like the ball screw set here under $50 these linear rails to three hundred dollars total so it's not inexpensive you're going to have you know I don't know yet but you know easily $1,000 in a little machine like that so what's it for and why are we why do we have pneumatic cylinders well the thought for this machine for me right now is I want a better way to engrave I engrave on the tormach it works and if you want to engrave on CNCs you can even use really cool spring-loaded tools like this from 2l Inc they compensate for minor variations and chip load and lots of things like that that are they're not complicated but you have a long discussion about it but the end of the day the tormach is just not a great machine for engraving it's only a 5,000 rpm spindle and I would engrave with the 20,000 rpm spindle if I had it but more so I've got a great machine that's really capable that's tied up doing things like engraving and it's it's slow or the trade-off is you wear out tools more quickly and we do um we do I don't say a lot of engraving but you know we want to engrave these hitch covers where you can see this one hasn't been painted yet so you see the weld marks but it grooves on the in that mild steel and we like to engrave our rimfire steel targets with our logo right here and it looks nice so the thought was hey I have no problem investing the little machine and hopefully we can have it nice and easy set up where you can just drop a fixture plate on there that lines up these different parts hit go and we're going to use this for now cheapo pen engraver now I will readily admit this will probably be the first thing we upgrade if the whole thing works but this is sort of the weak spot but this was super inexpensive and I figured it's a place to start and we'll try experiment with it later so let's talk a little bit more about what ball screws and linear ways or linear rails are and then let's look at the SolidWorks model and figure out the plane for how we're going to build this thing so what we've got here is a ball screw the ball nut and then a linear rail with a linear rail bearing block let's talk about the ball screw real quick these things are really cool you can buy various grades of the various Precision's and grindings we're not going to get into that of what matters is how this thing works and it works because there's a series of recirculating balls inside of this nut also it makes it expensive if that doesn't make sense take a look at this video and you can actually see there are small ball bearings not dissimilar from what you would see in a regular bearing that we're all a little bit more familiar with that rotates around like you would have in your the wheel of your car tire of your car and they provide a number of things including low friction mechanical advantage you know transfer of power accuracy preload there's just a huge reason why these things are really really cool and they're really fun to play with to buy these right now I actually recommend eBay and here's and they're from China and here's why I think you're going to be best off buying this as a kit you're going to ball screw with the ball nut and then the end blocks and you really want that because if you look this is going to come with a kit which is going to have a ball screw that's been turned down and then threaded and for a nut and then thread or then turn further down for a Oh for a coupler that's going to make to your stepper so it really just you know I don't even think it costs how much more if any and you're really going to save yourself from headaches so you can see here's the exact one that I purchased on eBay and again just if you don't buy the kit you'll have to spend some time making sure you get all the parts that made up okay now let's talk about linear rails these guys are also not inexpensive but I'm actually really happy I found these from automation overstock and as you can see here the bearing block is thirty six dollars and then this rail is five hundred millimeters and that's thirty six dollars so each one of these 72 or 144 for the pair that's actually really inexpensive one of the reasons these are inexpensive is they are only tapped from the back side there's no through holes for countersunk screws that makes a little trickier to work with but we we're going to show you how we take care of that in SolidWorks these things are also amazing the idea here incredibly low friction you can move them around really fast and they just don't twist they are solid as a rock which is really cool how do those work let's take a closer look we've got this barring that we haven't put on yet let's zoom in and look at the balls as we slide this spacer out you can actually see the balls moving inside that spacer and we just carefully do that's all I'm going to do you can see the balls right there so literally they recirculate through that how cool is that so there's the beginning of our rail let's go ahead and slide this guy on here you just use the rail to push the spacer out that way you shouldn't lose any of the balls like so perfect so let's take a look at what all this means with a model and don't laugh but I first thought I would actually consider just designing this in my head and just sort of whipping it up absolutely needed to model it so here is the SolidWorks model and if you take a look you'll see we've got this base plate that was actually sitting on the table a minute ago with the linear rail and ball screw on it and then we are fastening those linear rails to little pieces of one-inch aluminum angle on the sides that'll let us tap into these and fasten them because they're only again threaded on the underside what we have to pay attention to is keeping these two rails pretty darn parallel because otherwise the machine would bind as it traveled along this axis you see we've got the ball screw under there and that's another really important reason you have to model this up as you'll see it matters how you mate the gantry to the ball screw nut because you want to make sure you try to maximize travel of the machine and actually sort of a lesson I learned I should have bought a slightly longer ball screw than I did because you can see we're only going to have machine travel from well and you can see the pen will sit in this piece here from there to right about there so right at the edge of the machine or so not the end of the world for right now but something for you to consider if you're going to design one of these on your own the y-axis IPTS you see here I actually purchased from eBay because it was a I thought a good price and I thought well let's just try that and see I was trying to make this as little machine as I can because not everybody has a machine shop it could make all these parts on their own so this is a twelve and a half you see here twelve point seven five inch slide they call it for a 3d printer it's slightly lower quality than the linear rail stuff but well we're going to see how it works and see how it goes so that's one option is something sort of half pre-made so that's pretty straightforward you can see the one stepper here for the x axis and then the other the y axis stepper would be there and then for the Z or the plunge what we've got is the hole here that's not filled will be where the pen mounts and then these two guys here are those little bimba pneumatic cylinders so when you want to engage the machine to engrave you'll do two things you'll plunge those down with a pneumatic solenoid that I don't have yet but we'll cover in the next episode and then you'll also turn on air to the engraving pen that Allah caused it to be marking the metal and then the machine will start to move so in theory pretty simple right so next up for me I need to make some of these parts whip them up not too many things to do and then we're going to start put it together again as I mentioned the thought here with the alignment of the angle brackets to keep them parallel is to use four dowel pins and have those precisely located I hope that's enough the machine will be it'll be flexible enough that there'll be some give to it but I don't want it to be I want to I don't to fight the wrong battle I want to have it as accurate as practically possible the other thing we could do is mount them on there and then actually machine them square but that's kind of a pain in the butt I'd really rather not have to do that otherwise I think it's going to be hopefully smooth sailing so let's I'm going to go whip up some parts here we'll be back next week for the next episode hope you guys have enjoyed if you have folks thumbs up comments below I'm really excited for this build the tire gray things about the tiny-g board it's supposed to be really powerful responsive like i said adding limit switches and making this into like a little turnkey machine for a very little amount of money you can have a very precise machine it's like a second or third op type of machine and I think I'll build more of these if they work as well as they do this machine is also I think going to be totally rigid enough for some sort of a spindle if you want to actually have a milling or machining op instead of the pneumatic engraving that's the hope at least we'll find out next week take care folks stay tuned see you soon [Music] you

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