Simple Ball Foot

thingiverse

In many cases it is necessary to equip small pieces of furniture and equipment with additional feet which allow them to be moved easily. In other situations, it is necessary to allow a surface resting on a table to rotate, without altering the objects resting on it. In all these situations, a series of 3, 4 or 5 ball feet can be useful, which allow easy translation/rotation. They can also be fixed to the bodies to be moved using screws or a layer of double-sided tape. My first intention would have been to make the complete foot in parametric design and with the tecnique of the "print en place". The parametric design of the foot was quite easy in Fusion 360, however the problems arose at the time of printing: making two almost complete spheres in "print en place" did not give the desired results, due to the inevitable "welding points" that are created when printing the profiles of the two endo-contained spheres (hollow sphere and full sphere), and unless exaggeratedly increasing the value of the interspace which detracted from the functionality of the finished whole. Therefore I decided to redefine the project, unpacking it into three pieces: the base and the closing cap, which is screwed onto the base itself, as well as the plastic sphere. For the robustness of the whole, also subjected to considerable loads, I recommend using the following printing parameters in the slicer: - minimum number of perimeters: 6 - minimum number of lower and upper layers: equal to the above number of perimeters - layer height with 0.4 mm nozzle: 0.16 mm - minimum filling: 20% - preferable material: PETG - supports: wherever necessary. Pay particular attention when removing supports from the printed parts so as not to cause damage to surfaces and moving parts. - positioning on the printing surface: as in the attached illustrations For greater durability I suggest to try to print the pieces with harder Nylon filament. If available, you can use a sphere of metal, glass or plastic, instead of a 3D printed sphere (diameter 20 mm - tolerance plus or minus 0.1 mm). Bearing in mind that this design has a 20mm ball and a 2x0.40mm slip tolerance, it is possible to scale the base and cap to fit any high ball available (such as a squash ball or golf ball ...) using as scale factor the ratio of the diameters of the actual sphere (in mm) divided by 20 mm. You will find attached two sizes of the 20 mm sphere, which differ in the level of tolerance, which you can choose according to the printing capabilities of your printer and the greater adherence to the spherical seat of the foot. In the case of using a 3D printed sphere, an initial running-in period is recommended to allow for the leveling of the mutually sliding surfaces. DISCLAIMER It is your responsibility to determine suitability for the intended operating conditions, especially in view of the fact that the pieces are subject to considerable loads and wear phenomena, therefore use them with caution and evaluate the case-by-case applicability, performances and risks in advance!