Summary

Yet another coin fidget spinner. This one is a tiny three arm version. it uses stacks of four 1 euro cent coins per arm and a 5 mm × 11 mm × 5 mm bearing, called “685”, in the centre.

It’s small enough to palm, which may come in handy when someone doesn’t want you to use one.

Print Settings

Rafts:

Doesn't Matter

                                            <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                        <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>With the rounding, the contact area isn’t too big, so a raft or brim may be useful.</p><p>The <code>.obj</code> file is the newer version, the <code>.stl</code> the previous. I have no idea why the <code>.obj</code> apears standing in image. Slic3r shows in lying flat, and that is, of course, the way it should be printed.</p></div>

How I Designed This

This is slightly parametric. Whit a bit of work you can use your favourite coins, either local currencies, or parts of that little pile of foreign currency that travellers tend to collect. For that i have included the FreeCAD files. They include a spreadsheet called “sizes”. To get a new spinner, do this:

Download FreeCAD and get it running
Load the 685_coin_spinner_3_arm.fcstd FreeCAD file
In the tree view, double click on “Sizes”. You should see the spreadsheet
Measure your coin or look up its size (Wikipedia, search engine, &c.)
Put in the diameter and thickness in B6 and B7. Make sure to keep the = and mm.
Check that you have enough coins. The spreadsheet shows the number needed. Typically 12.
Change other values in the “B” column, like the whole spinner’s size, to taste.
Go back to the 685_coin_spinner_3_arm view
Check that the shown shape looks OK. There are view controls at the top
Check that in the tree view there are no exclamation marks as warnings
If there are problems, it’s easiest to close without saving and to try again. Change fewer values, and only by small amounts.
If the spinner looks good, select the last item, “spinner”. It should turn green in the main view.
Look for the dropdown in the tool bar and select “Mesh Design”
You should now have a “Meshes” menu. Select “Create mesh from shape …”
I have to select the “Standard” radio button. “Mefisto” produces empty meshes.
Click OK
There should be a “spinner (Meshed)” item in the tree view. Select it.
Click on the “Export a mesh to file” icon, enter a file name, select the file type (STL or OBJ) and click “OK”,
Et voilà, you’re done. You have finished your first FreeCAD lesson and can now go ahead and slice and print your customized spinner.

There is also some design history available at my github repo.

I redesigned this a bit, and simplified the FreeCAD file. Hopefully changing the sizes as described works a bit better now.

yacs three arm mini coin spinner