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IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > Purchasing the right linear rails for a home made cnc router table
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  1. #41
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by MajorTendonitis View Post
    Sorry as my terminology isn't this great yet . When I refer to the X axis , I mean the main beam that's holding the spindle . I refer to the sides as the Y axis


    A concern I have is trying to get the centre of gravity right for the spindle . I like how cncrp has the horizontal 3060 of the gantry secured on top of the vertical sides .
    In my case I was going to secure the 3060 to the front of the vertical extrusion, but secure the vertical extrusion towards the back of the plate , which will help a bit .
    I need to fire up my laptop and use sketchup to illustrate better .
    Naming the axes depends on how you set it up in your controller. Usually the longest axis is called X, with the shorter axis Y and the vertical axis Z. Sometimes however, the gantry is the longer axis and the part is loaded facing the gantry, and the machine is set up such that the gantry is the X axis. It doesn't matter one bit. If you really needed to, you can make a profile for each orientation. It's a lot easier, however to just rotate the part in CAD or CAM!

    As long as you have the spindle center somewhere between the footprint of the gantry bearing blocks, I think you'll be fine. You may find that getting the CG over the center of the bearing blocks moves the spindle past that bearing footprint, which would increase the amount of rail needed to get the travel you want.

    Looking at the CNCRP PRO kits, it looks that Gerry's spot on about that gantry beam being 80160... If you held a piece of 3060 in your hand it would become patently clear that it won't do for a 5' span.

    One thing to consider when designing your machine would be to incorporate raised rails on the long axis; that is, the extrusion, linear guides and motion components are above the surface of the table. This would eliminate having to engineer the uprights, which should lead to a more stable and rigid gantry. Reach-in to the machine may prove a little more challenging, but the overall machine height could be lowered slightly to accommodate that.

  2. #42
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    164

    Re: Purchasing the right linear rails for a home made cnc router table

    Ok guys I stand corrected , 80160 is available where I was going to purchace it .
    Metric T-Slot Technical Data | Rocky Mountain T-Slot Aluminum Canada

    I didn't realize that was the metric version , and I'm liking the fact that it's a little bigger . Thanks again all ,as I wouldn't have caught that , and I will be ordering it instead when the time comes

  3. #43
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by louieatienza View Post
    Naming the axes depends on how you set it up in your controller. Usually the longest axis is called X, with the shorter axis Y and the vertical axis Z. Sometimes however, the gantry is the longer axis and the part is loaded facing the gantry, and the machine is set up such that the gantry is the X axis. It doesn't matter one bit. If you really needed to, you can make a profile for each orientation. It's a lot easier, however to just rotate the part in CAD or CAM!

    As long as you have the spindle center somewhere between the footprint of the gantry bearing blocks, I think you'll be fine. You may find that getting the CG over the center of the bearing blocks moves the spindle past that bearing footprint, which would increase the amount of rail needed to get the travel you want.

    Looking at the CNCRP PRO kits, it looks that Gerry's spot on about that gantry beam being 80160... If you held a piece of 3060 in your hand it would become patently clear that it won't do for a 5' span.

    One thing to consider when designing your machine would be to incorporate raised rails on the long axis; that is, the extrusion, linear guides and motion components are above the surface of the table. This would eliminate having to engineer the uprights, which should lead to a more stable and rigid gantry. Reach-in to the machine may prove a little more challenging, but the overall machine height could be lowered slightly to accommodate that.
    I consider the X axis to be the one that has the spindle on it going from side to side traveling along the gantries main beam, which in my case I'm shooting for 50" of cutting area . I consider the Y axis the side carriage plates that hold the gantry up, and was going to go a little longer , like around 60" of cutting area .
    Sorry if I'm confusing everyone , as now I'm really confused lol.
    And yes I read you can configure them each way in Mach3/4 , UCCNC etc . As per Ger21 I'm going with UCCNC.

    I would have sworn the Y axis on cncrp 4x8 table , was considered the 8' of travel ?

  4. #44
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by MajorTendonitis View Post
    I consider the X axis to be the one that has the spindle on it going from side to side traveling along the gantries main beam, which in my case I'm shooting for 50" of cutting area . I consider the Y axis the side carriage plates that hold the gantry up, and was going to go a little longer , like around 60" of cutting area .
    Sorry if I'm confusing everyone , as now I'm really confused lol.
    And yes I read you can configure them each way in Mach3/4 , UCCNC etc . As per Ger21 I'm going with UCCNC.

    I would have sworn the Y axis on cncrp 4x8 table , was considered the 8' of travel ?
    There's no confusion... if you set your part up in CAM with the long side along the X axis, then you set up your machine the same way. Generally, however with a machine like a 4 X 8, it's almost always programmed that the X axis is the long axis. Some people here care for whatever dumb reason, but guess what? The machine doesn't care. Take the smallest form of gantry router, a desktop router or 3D printer or laser engraver. Left and right would be X, toward and away would be Y, and up and down Z. Whichever way you orient your part and load the workpiece onto the machine usually determines how you name each axis.

  5. #45
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by louieatienza View Post
    Left and right would be X, toward and away would be Y, and up and down Z
    That's the way I interpret it to . Now just to convey that when I talk about my build

  6. #46
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by MajorTendonitis View Post
    That's the way I interpret it to . Now just to convey that when I talk about my build
    To avoid confusion, just call it the gantry the gantry! The Z axis can be called the carriage. The table can be called the table or bed.

  7. #47
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    Re: Purchasing the right linear rails for a home made cnc router table

    The convention is (generally) when you are standing in front of the machine:
    X moves side to side
    Y moves front to back
    Z moves up and down

    This is because of how you do things in CAM.

    The reality is that you can arrange it however you like.
    7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)

  8. #48
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by louieatienza View Post
    To avoid confusion, just call it the gantry the gantry! The Z axis can be called the carriage. The table can be called the table or bed.
    Sounds good

  9. #49
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    Re: Purchasing the right linear rails for a home made cnc router table

    I know a gentleman who happens to have a bunch of size 20 linear rails and bearing blocks for sale. And he's located in Canada. I sent you a PM with the info in case you're interested.

  10. #50
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    Re: Purchasing the right linear rails for a home made cnc router table

    Funny I also know a guy happens to have about (20) size 35 HD Hiwin bearing blocks and about 10 matching rails!

  11. #51
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by Paul-JB View Post
    Funny I also know a guy happens to have about (20) size 35 HD Hiwin bearing blocks and about 10 matching rails!
    35mm , well that's just overkill lol . I think I'll stay with 20mm


    Quote Originally Posted by Paul-JB View Post
    Funny I also know a guy happens to have about (20) size 35 HD Hiwin bearing blocks and about 10 matching rails!
    Paul I'm tempted to phone him . Ill probably procrastinate to long and they will all be gone .

    I'm tempted to buy a 4x4 Pro from CNCRP after looking at the costs of all my parts . I really wanted to build my own though

  12. #52
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by MajorTendonitis View Post
    35mm , well that's just overkill lol . I think I'll stay with 20mm
    True that

  13. #53
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    Re: Purchasing the right linear rails for a home made cnc router table

    If you're not sure, I'd say, don't do anything. Take some time to consider your options.

    Is this for a hobby or for a business? If part of the fun is the build, then I'd say you should take that route.

    The pitfall I think comes when people build things but don't know what they are doing and don't ask advice, or they get the wrong advice or they get cheerful enthusiastic comments and not enough criticism. Then at the end of the day they can end up with a pile of expensive parts that is worth very little. There are so many horrid designs I've seen, but also, there are some really fantastic ones. Also, even commercial manufacturers get things wrong some times. Some of the worst designs I've seen are from commercial places actually. I'm not talking about CNCRP, please don't assume that, but I don't want to name names of the ones I am thinking of.

    If I had to do my first build over again, which I am kind of doing now, I would not use any T Slot. Big steel tubes bolted together for adjustability. There are probably some available at a scrap yard near you. For 1/10th of the cost of T Slot. You can get the mounting surfaces flat by using epoxy. In fact you can use the epoxy sandwich method I thought of. 6x6x0.25 tubes should be plenty better than T-slot. Can you weld (It would be handy but you can probably get by without it if you think it all through)? Do you have a mini mill or at least large drill press? Are you hand at cutting, grinding, painting steel? Would you describe yourself as a patient person? Can you draw this whole thing up on your computer before you start construction? Are you willing to learn that stuff and is it something you would enjoy? It's not hard really. Anyone can learn it if you don't already know. I have no idea of your experience level so I mean no disrespect by saying that.

    The other option is to wait for something great to come along. Last year I saw an add for a Biesse Router, a really nice big one, supposedly fully functional, the guy bought it and then realized he didn't have the power needed to run it. Only $2500 CAD bucks. Well I know I could retrofit that to run off single phase 220, perhaps not with all the bells and whistles working, but still......I had no where to put it. I am working on my new build in a small room in the basement of where I live now. No shop or garage to speak of, and how would I move it, it weighs 6000 lbs or something like that. So I hesitated, and it was gone the next day.

    Someone on here has some Seiko Robots he might sell......there's another option. Use the linear stages from something like that. I don't know. Take your time and be sure of what you want before you buy, that is, if this is for a hobby. If it's for a business, buy something that works and get on with it.

    And I don't think 35mm rails are overkill if they come at the same price. Ballscrews, that's a different matter because there is spinning inertia to overcome. But rails, meh, if you can get a sweet deal on 35s for the same price as 20s, there's no harm in that!

    Perhaps you could start by making some drawings of what you want to build and go from there. There will always be deals to be found.

  14. #54
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    Re: Purchasing the right linear rails for a home made cnc router table

    Thanks again for all the info guys . NIC 77 , you make some great points . This is for hobby , and after seeing how the mechanics work, it doesn't seem to be rocket science , close though .

    I have a 22" General drill press, router table , metal chop saw , and a 210 Lincoln welder . Wish I had a cnc mill and new how to use it .
    I agree with your idea of the T slot not being the best choice , but I think I will have to use it for the bed sides and gantry at the very least , as I'm sure it's the only way I'm going to get any accuracy assembling the rails and gear rack .
    I'm also in no rush , as I'll work on it as I get time this winter . I joined Joes cnc forum and I've been looking at Joes Evolution design , and wanting to use some of its measurements, but use linear rail as I'm not liking angle iron . I'm not very good with sketchup yet , but would like to show you guys some of my ideas before I proceed .

  15. #55
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by NIC 77 View Post
    If you're not sure, I'd say, don't do anything. Take some time to consider your options.

    Is this for a hobby or for a business? If part of the fun is the build, then I'd say you should take that route.

    The pitfall I think comes when people build things but don't know what they are doing and don't ask advice, or they get the wrong advice or they get cheerful enthusiastic comments and not enough criticism. Then at the end of the day they can end up with a pile of expensive parts that is worth very little. There are so many horrid designs I've seen, but also, there are some really fantastic ones. Also, even commercial manufacturers get things wrong some times. Some of the worst designs I've seen are from commercial places actually. I'm not talking about CNCRP, please don't assume that, but I don't want to name names of the ones I am thinking of.

    If I had to do my first build over again, which I am kind of doing now, I would not use any T Slot. Big steel tubes bolted together for adjustability. There are probably some available at a scrap yard near you. For 1/10th of the cost of T Slot. You can get the mounting surfaces flat by using epoxy. In fact you can use the epoxy sandwich method I thought of. 6x6x0.25 tubes should be plenty better than T-slot. Can you weld (It would be handy but you can probably get by without it if you think it all through)? Do you have a mini mill or at least large drill press? Are you hand at cutting, grinding, painting steel? Would you describe yourself as a patient person? Can you draw this whole thing up on your computer before you start construction? Are you willing to learn that stuff and is it something you would enjoy? It's not hard really. Anyone can learn it if you don't already know. I have no idea of your experience level so I mean no disrespect by saying that.

    The other option is to wait for something great to come along. Last year I saw an add for a Biesse Router, a really nice big one, supposedly fully functional, the guy bought it and then realized he didn't have the power needed to run it. Only $2500 CAD bucks. Well I know I could retrofit that to run off single phase 220, perhaps not with all the bells and whistles working, but still......I had no where to put it. I am working on my new build in a small room in the basement of where I live now. No shop or garage to speak of, and how would I move it, it weighs 6000 lbs or something like that. So I hesitated, and it was gone the next day.

    Someone on here has some Seiko Robots he might sell......there's another option. Use the linear stages from something like that. I don't know. Take your time and be sure of what you want before you buy, that is, if this is for a hobby. If it's for a business, buy something that works and get on with it.

    And I don't think 35mm rails are overkill if they come at the same price. Ballscrews, that's a different matter because there is spinning inertia to overcome. But rails, meh, if you can get a sweet deal on 35s for the same price as 20s, there's no harm in that!

    Perhaps you could start by making some drawings of what you want to build and go from there. There will always be deals to be found.
    There ARE concessions to be made by using the 35mm rail. I happen to have a matched set, I believe 1200mm OAL, and the box weighs over 75lbs. I don't think you'd ever truly take advantage of them as everything has to scale up - frame, drive syatem, motors... even fasteners such as screws and t-nuts (for t-slot frame.)

    They're nice to have if they can be utilized, otherwise it's a waste of money and time regardless the price. You're far better off with a stiffer frame with a more reasonably sized LM rail.

  16. #56
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    Re: Purchasing the right linear rails for a home made cnc router table

    Major - Read through the thread and had one thought concerning extrusion- vs - steel: Extrusion helps you get the rails on straight, with steel you'll have to figure out a way to mount your rails straight and flat. I made one machine out of extrusion on top of a steel base that I leveled with epoxy. The epoxy became my base and my reference surface for setting everything even and parallel.

    And ref 20mm vs 25mm rail: Like Ger21 says, you're never likely to approach the loading capacity of the 20mm rail let alone the 25mm. But if they are very similar in cost I would go with the 25mm if you plan on using extrusion. I think Jfong referred to this... The 25 mm rail will bolt better to the extrusion because its wider. The extrusion lip is bent inward at about 2 degrees. When you tighten a fastener into the slot, the fastener tension pulls this lip outward/upward flat to your rail. A wider rail will bridge this depression better than a narrower one. How much better???? ... hard to say. But if they are essentially the same cost there's no drawback.

  17. #57
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    Re: Purchasing the right linear rails for a home made cnc router table

    1Jumper10 , I have gone threw some of your threads , well almost every page of your 2nd build for a friend . It was the blue frame with black epoxy , and I was absolutely blown away !
    It just doesn't get any better than that

    I never even thought of using epoxy , and thought it was genius , as how can it be any more precise than that is beyond me . Dam I wish I was one of your close friends lol .

    Regarding linear rail , how it sits on T slot was a concern , so I won't go smaller than 20mm . I was thinking of making a metal base as you did , but instead of epoxy , I was thinking about shimming the t slot on the metal base .
    But of course epoxy is the ultimate. I tried to find the page where you mentioned the price for the epoxy , but couldn't find it again.
    I would have sworn it was around 700 bucks , but I could be way off ? Ger21 has found a link for me where the prices were much better than I thought .

    I don't know how you figured out the height required of those steel vertical plates that stick out of the epoxy in order for them to bolt to the T slot in the exact right spot? Nice work

  18. #58
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    Re: Purchasing the right linear rails for a home made cnc router table

    Thanks.
    The epoxy was $300 delivered.
    The anchors you're referring to we located by temporarily placing the extrusion frame on the base with a half inch spacer to account for the epoxy, clamped them to the extrusion where we wanted them, and welded them to the base. Afterward we just lifted the extrusion off and eventually poured the epoxy around them. When we placed the frame on the base after the epoxy was cured, the fit was great but a meniscus formed around the anchors that needed to be removed.

    Sent from my Pixel XL using Tapatalk

  19. #59
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by 1Jumper10 View Post
    And ref 20mm vs 25mm rail: Like Ger21 says, you're never likely to approach the loading capacity of the 20mm rail let alone the 25mm. But if they are very similar in cost I would go with the 25mm if you plan on using extrusion. I think Jfong referred to this... The 25 mm rail will bolt better to the extrusion because its wider. The extrusion lip is bent inward at about 2 degrees. When you tighten a fastener into the slot, the fastener tension pulls this lip outward/upward flat to your rail. A wider rail will bridge this depression better than a narrower one. How much better???? ... hard to say. But if they are essentially the same cost there's no drawback.
    I don't know why no one has used, let's say, 3/8" by 1.5" aluminum flat bar between their rails and the T slot hole. It seems to me that this would make using T-Slot a better set up platform for proper rails if you're concerned about having enough surface area on the outside of the T-Slot Slot.

    Flatbar is inexpensive, conforms to the surface you bolt it to, and all you'd have to do is drill a few through holes.

    Quote Originally Posted by MajorTendonitis View Post
    I would have sworn it was around 700 bucks , but I could be way off ? Ger21 has found a link for me where the prices were much better than I thought .
    Alternatively, if you're still set on using T Slot for the sides of your machine, you could consider an underframe and table that was carefully made using braced wood 4x4's.

  20. #60
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    Re: Purchasing the right linear rails for a home made cnc router table

    Quote Originally Posted by NIC 77 View Post
    I don't know why no one has used, let's say, 3/8" by 1.5" aluminum flat bar between their rails and the T slot hole. It seems to me that this would make using T-Slot a better set up platform for proper rails if you're concerned about having enough surface area on the outside of the T-Slot Slot.
    It's actually been done on a few builds here, though I suppose many that build here with t-slot, in practice, see deviations in flatness less than .005" which would be good enough for most stock linear rail, under the loads put on them in the "DIY" world....

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