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  1. #11
    Quote Originally Posted by jimbo_cnc View Post
    I'm not sure I agree with your theory for putting the legs in the corners, but we won't worry about that now.

    I'm interested in how to make it moveabe and still no twist. Obviously, making it very stiff is a good start. But what you really want is to know the reaction forces with the ground so you can install the machine elsewhere with same contact forces. The reactions don't need to be equal but equal would be sensible.

    If you have screw adjusters on each foot, then the torque is an approximate measure of the contact force, so you would carefully go around the machine and even up the torque on each foot adjuster.

    You want to do this before your epoxy pour.


    Or maybe thick elastomeric pads, where you can measure the deflection as an indicator of reaction force. These might be good for vibration too. What is your plan for fixing to the floor? or does it just sit on the floor ?

    Some numbers would be useful. Have you calculated the stiffness of the frame? eg if all the weight is on 2 opposite corners how much dip at the other 2 corners?
    i am still not sure. When all is ready and un-leveled, we will see if i am right or wrong. If i had made a table and not all on the floor, the frame would be even stiffer, so that would not be an issue. But As you can see the garage is very small, lets say it will be the machine enclosure :-).

    On paper if the table hangs in the air one side and somehow is supported only by one side/cantilever/ the bend will be around 0.03mm or less. In normal conditions with 500 kg gantry in the middle less than 0.03, so for the side twist.
    So basically if i have not made any mistake all must be well under 0.05, which seems quite an achievement to me for 3000x1800frame, having in mind it has only 500kg steel in it.



    Now my wife went a week before to Bulgaria on a business trip. It is our country of origin so i know where to make it cheaper than here, she managed to order the rest of the laser cut parts, the rotating nut parts, collect them , pack the and bring them to me. Meanwhile emptying on the way back all personal things of hers, cause this weight exactly 32 kg with the suitcase. I could only bow to her for the support.







    I wonder how the 2 bearings go against each other? The thick inside ring side should be outside or facing each other? Somebody shed a light please!

    I have to find my bloody caliper in the garage, cause the bearings don't enter without force at all. I called today and they said that they made all so that it must be press fit, something like 0.03mm more. I dont have an idea about that, will see how i fix all inside. First will have to bore the 30T pulley. Though actually i am still in a doubt to use the Chinese aluminum pulleys i bought from ali express or order new from belting online. cause some of the chinese pulleys the 20t ones were not straight, though i kept them for the sake of the price. 10x30t pulleys+10x20t pulleys=~86 euro. Having in mind i could not find cheaper than 13-15euro aluminum pulley 30t, one piece.
    Unluckily, belting online had only steel ones and even they were getting expensive with the machining.


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    project 1 , 2, Dust Shoe ...

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