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  1. #11
    Quote Originally Posted by JAZZCNC View Post
    I spread a layer of Epoxy putty on the bottom plate. Then I put layer of plastic between rails and plate then lightly tighten together pushing some excess out then set the rails on same plane and parallel etc. The putty gives plenty of time for adjustment and dries hard has metal.
    It has dampening quality's has well so helps with vibes transferring thru frame. It drills and taps easy and fills any voids, I can shape to match radius etc and it easy grinds and sands if needed.
    When set 24hr later I have a perfect hard surface that sets rails exactly on same plane. The rails can be removed and go back exactly on same level so no messing around with shims etc.
    To be honest, as my english arent good , i dont understand excactly what you did
    When you say "I put layer of plastic between rails and plate" what you mean? what kind of plastic ? and when you say "between rails and plate" what do you mean? Your rails rest on a plate or on a square beam ? Sorry for asking but i dont get it

  2. #12
    Quote Originally Posted by ba99297 View Post
    2. For the rails support beams I am between these profiles
    80X80 4 mm
    80X80 5 mm
    100X100 4 mm
    100X100 5 mm
    and for the table structure
    80X80 4 mm or
    80X80 5 mm
    i want your advice
    Any of those will be fine. Personally If mainly wood use then I'd go with 80x80x4 and save some money has it will be plenty strong enough.

    Quote Originally Posted by ba99297 View Post
    Jazzcnc when you say "MUST surface the table to be sure it's parallel to Cutter" you mean that the spindle should make a full pass over the cutting table and milling the table surface ?
    Yes exactly.

    Quote Originally Posted by ba99297 View Post
    1.when you say "adjustable top rail and careful measurement" you mean the X ( long) axis rails should be adjustable right?
    Yes exactly.

    Quote Originally Posted by ba99297 View Post
    2.when we talk about self leveling polyester epoxy, is it specific epoxy or common marine polyester can do the job. Should i need a primer in order the epoxy to bond with the metal?
    It must be solvent free epoxy to avoid shrinkage. No primer is needed just very clean oil free surface also best if rough surface so epoxy binds to it better.

    Quote Originally Posted by ba99297 View Post
    When you say "digital drives" you mean the motor drives. I reminds you that i will use 400watt yaskawa servo motors Sigma II generation
    Yes sorry forgot you where planning to use servos.


    Quote Originally Posted by ba99297 View Post
    My main concern of using epoxy is the aging and the temperature effect to the table. I am talking about contraction expansion. The machine will be placed at my basement where i have temperatures from 8 ( winter ) to 26 ( summer ). Would that be a problem?
    I've not had any problems with heat/cold, My workshop can go from -8 (winter) to 30 (summer thou rare here in UK) so don't think you will have a problem.

    Quote Originally Posted by ba99297 View Post
    What will happen if one day i decide to move the machine to another place.
    Nothing will happen everything will remain the same. Remember the Epoxy is not to level the machine.!! . . . It's just so the two rail top surfaces self level on the same plane.
    To give an massively over exaggerated example.!!
    Imagine the rails or the full machine before applying epoxy are not on level surface, lets say 10deg slope. When you apply the epoxy to rails they will self level on the same plane. Looking at the epoxy From the side it will have 10deg taper.
    If you then move the machine to a level surface the rails will slope 10deg . . BUT . .They will still be on the same plane provided the frame is stiff and doesn't twist when you move it.
    This is why My machine works in vertical position(15deg angle) because doesn't matter if the rails or bed are at an angle only matters that the two rails are on the same plane.

    Quote Originally Posted by ba99297 View Post
    The truth is that epoxy look a good and easy solution, on the other hand i don’t fell good if i don’t have the ability to adjust.
    The idea of epoxy is so you don't have the need to adjust.! . . BUT . .If you want the best of both worlds then have adjustable top rail and epoxy the surface has well. . . This way you can fine tune using shims if you feel the need.

    Quote Originally Posted by ba99297 View Post
    Also do we know how epoxy reacts. It is more than sure that epoxy doesn’t have the same contraction expansion ratio as steel. I have heard that pro builders that use cast iron, leave the metal for aging for 10 years...
    I've been using the Epoxy method for 3-4yrs now and I've not had any issues but if you want to be 100% sure and follow tradition then leave it to set for 10 years. . .Lol . . .( By which time we will have moved on to making DIY Star trek Replicators . . )

    Quote Originally Posted by ba99297 View Post
    To be honest, as my english arent good , i dont understand excactly what you did
    When you say "I put layer of plastic between rails and plate" what you mean? what kind of plastic ?
    The layer of plastic is just a barrier to stop the top rail being bonded to the mounting plate so it can be removed. When the Epoxy putty has set hard the rail is unbolted and plastic barrier is removed and thrown away. The plastic can be any type, old carrier bag anything. Someone suggested to me taping the rail with parcel tape which I did try and does work ok.

    Quote Originally Posted by ba99297 View Post
    when you say "between rails and plate" what do you mean? Your rails rest on a plate or on a square beam ? Sorry for asking but i dont get it
    Look at the picture Eddy posted and you will see the plates which the rails bolt onto. Epoxy putty is then spread on these plates, then piece of plastic placed between rail and epoxy to stop bonding together.
    I then set the rails on the same plane and parallel with a combination of temporary shims and adjusting bolts. Effectively the Epoxy putty is acting has a Permanent shim when dry.

    Hope this makes more sense.?
    Last edited by JAZZCNC; 17-10-2013 at 12:37 AM.

  3. #13
    Quote Originally Posted by ba99297 View Post
    First of all thanks everybody for the participation to the thread.
    Next i would like to introduce some of my conclusions and ask some things about all these that i have already read

    1. I beam will not be used
    2. For the rails support beams I am between these profiles
    80X80 4 mm
    80X80 5 mm
    100X100 4 mm
    100X100 5 mm
    and for the table structure
    80X80 4 mm or
    80X80 5 mm
    i want your advice
    Look from what you started and where you jumped- 100x100x4 and 100x100x5

    Read again what Dean /jazzcnc/ told you, first be sure for what you use it mainly and then decide on the thickness. Go to your local metal shop and check for your self about the 100x100x5 and 80x80x5. This is way too much. Ok, people use them but for builds that intend to cut mainly aluminum and so.



    Quote Originally Posted by ba99297 View Post
    My main concern of using epoxy is the aging and the temperature effect to the table. I am talking about contraction expansion. The machine will be placed at my basement where i have temperatures from 8 ( winter ) to 26 ( summer ). Would that be a problem? What will happen if one day i decide to move the machine to another place. The truth is that epoxy look a good and easy solution, on the other hand i donít fell good if i donít have the ability to adjust. Also do we know how epoxy reacts. It is more than sure that epoxy doesnít have the same contraction expansion ratio as steel. I have heard that pro builders that use cast iron, leave the metal for aging for 10 years...
    Thanks again everybody. If anyone has something to suggest i am anxious to hear
    Don,t get me wrong, but your main concern should be squaring the rails in one plane. And choosing square supported rails, not roundish.
    I assume you don't have even a straight edge and you worry about contraction and expansion. First think do you need such an accuracy, then do you have the actual means to measure it, then how much is the cost of the tools to measure it...
    For wood and plastic and occasional aluminum you need much lower accuracy than you are contemplating.

    I mean relax, and be careful not to make some obvious mistake. Like making a cnc for another kind of job. remember the old saying: " The machine is strong as its weakest part". I constantly meditate on this when i catch myself overbuilding

  4. #14
    Just grabbed these out of a video I saw if any use

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    details are here 3D Model of CNC Router c4d, obj, 3ds, fbx, dxf, skp, iges
    and it looks like they had to add some triangulation to the legs after these photos
    Last edited by EddyCurrent; 19-10-2013 at 02:39 PM.

  5. #15
    So far thanks everybody for your answers
    Your advices keep me away from mistakes that i think could cost me money time and poor final result
    After all these answers, i decide

    to use part of Silyavskis' table plan ( for part of the table that the X rails rest on) .
    Not to use the I beams
    Not to use adjustable beams for the X axis rails and go on with the epoxy solution.
    This choice means that the table is solid as rock. So before i go on with the 3d design i want your advice about the table diagonal reinforcing.
    Here are some autocad plans. They represent side view of X axis. I design 4 solutions ( A,B,C,D )
    The upper yellow line represents profiled rails, and the green color is adjustable legs
    Tell me your opinion.
    I haven’t decide yet if i will go with 80X80 or 100X100 box section. It depends from the cost. The following plans are made with 80X80 box section
    Thanks for your time


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    Last edited by ba99297; 27-10-2013 at 10:15 PM.

  6. #16
    I like B but not everyone will

  7. #17
    I like A but if i were you, would turn the 4 diagonals 180 degree/ mirror them upside. That will separate on smaller sections and support even further the X rails support + when pushed from upside will make a stretching force to the lower beam, not pushing, as it is now.
    I mean instead of MM WW

    If full height is desired, as Eddy says B is best, simple and strong + the diagonals will stretch again the lower beam, if pushed from above. And we all know steel can not be stretched
    Last edited by Boyan Silyavski; 28-10-2013 at 05:14 PM.

  8. #18
    Silyavski before i check for any new post at my thread i design in autocad this

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    and then i read your post
    I think that we are thinking in the same way
    To be honest you inspire me for my table plan ( especialy for the rail support beams ) thank you.
    Aslo thanks everybody else like Eddycurrent and of course Dean for their ideas
    Day after day, thread after thread post after post i feel that the knowledge and the experience of people that willing to help, give me the ability to make a solid machine. You know it is very important to make a step and have no question to be answered. That is what i almost fell now about the table plan. May be some small changes will be done, but the basic consept i think is this.
    I will post 3d plans soon
    PS A machine that is having rail height at 70 cm from the ground, has any disadvantage compared to a machine that is having rail height at 90-100 cm from the ground?
    I will be happy to hear any other advice.
    The only question that is waiting for answer is the beam dimensions 80X80 or 100X100 and of cource the thickness
    And here i have some 3d plans.
    I will come back with another plan a little bit different
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    Last edited by ba99297; 29-10-2013 at 01:43 PM.

  9. #19
    It will work both with 100x100x3 and 80x80x 3 or 4mm. Depends on how strong would be your gantry, what spindle you will like to mount and how further you will like to push it.
    I suggest you make your gantry from 2 pieces of the same profile you will use soldered together, hence 200x100 or 160x80 or do it from aluminum, the way Dean makes his machines, with a ball screw hidden in the gantry, depends what means you have.

    The drawings look very good. Now if you aim at certain weight or to be able to pass through normal 1m wide door, don't make it higher . if you want to make it higher and at the same time light, just make the legs longer. Also if length, weight is a problem, you can lift the 4 lower beams to the middle of the M , and remove the middle leg below this point, this will not compromise the strength.

    If you aim aluminum and hard stuff mainly, maybe a gantry like Jonathans will be better, look at his exemplary build

  10. #20
    I suggest you make your gantry from 2 pieces of the same profile you will use soldered together, hence 200x100 or 160x80
    The gantry will probably made as you say from 2 pieces of 80X80 or 100X100 profile, covered with 10mm laser cut aluminium plate just for acuracy for the holes distances. This plate will be bolted on the gantry box section and may be adjustable in order to achieve paralelism with the table.

    depends what means you have.
    As for the means, i dont have mill i dont have lathe

    maybe a gantry like Jonathans will be better, look at his exemplary build
    I have read many times Jonathans thread. So many in order to understand what i am reading. NO COMMENT. What else can i say. I cant follow this plan beause it is out of my budjet, and i dont have the means and the knowledge to do such job. For now the only think i can do is design 4-5 type of tables and ask the polite guys of mycncuk to give me their advice and make their corrections
    Last edited by ba99297; 30-10-2013 at 10:54 PM.

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