l'astuce pour que la sphère ne dépasse pas le bord extérieur de la poulie est que j'ai fait une 1/2sphère en mettant l'angle de rotation à 180°

le sketch des nervures , je l'ai dessiner sur le plan YZ , Pad et polar x6 puis la Demi sphére je l'ai faite au milieu avec l'outil pour créér des forme primitive , mais de 180° degre d'angle , puis avec "Attachement" je l'ai fait bouger de 49mm et polar x6 une sphère soustractive pour la ...

you are new so the possibility of attachments was not allowed, now that your post is successful you can
at the bottom of the table to answer there is "Attachments" then further down "attach a file" you have 5 files of 1 MB maximum

when I say that it is the best method, there at the T moment of the D day
if you have to sweep all the parameters: center, TNP, Space, Universe, and eclipse days, you can do better, and since we spoke, you already have a lot

in the case of a construction anyhow, this is the best way

voilà , ça feras un franc

Bance you gave the right answer
now allow me to correct a big source of problems: avoid like the devil making sketches referenced to faces, do them on the general plans and use the "Inverted" flag if necessary
Avent that others tell you that they do this in 2 sketches

I think of the Step format you will have the saving of the finished object, importable into CAD which reads the STEP format
you will no longer see the tree structure or the sketches used, but you will be able to continue working on it via your other CAD

This is an important feature to know
full name is DatumPlan
it is the equivalent of one of the 3 main planes but adjustable in all positions
have a look in the Wiki: Google > Fc/tuto/Datumplan

seeing the underlying image, I suspected this reason
Furthermore you can use the main axes and when everything is finished, move the body using its placement
the disadvantage is that in the event of a copy or clone, it will return to its origin
you can also use one of the assembly workshops