My Fiat 500 Abarth has welded seam jack points. This is a simple adapter so I can lift the car without bending the seam. The SCAD file is setup so that you set the puck diameter then define its max dimensions. For example, if one of your lift points is too close to another rail it can clip the sides or ends. After I measured everything I ended up not clipping off any corners but the code is still there.

Pros:

• Exact fit
• Magnets to hold it in place while placing jack
• When the car is on the puck it is millimeters away from the jack itself. In the event of total failure of my printed part the car will still be on my jack.
• The car stays centered over the jack very well. Commercial pucks are much taller and look less forgiving if there are any lateral forces.
• Lifted several times with no visible damage to the car

Cons:

• Cast pucks won't shear like 3d printed parts can. My biggest fear is getting enough sideways force on the puck that it shears off one side and the car comes off the jack. Working on a clean smooth garage floor vs the street has eliminated those concerns.

Updates:

• Round outer edges
• Screws from bottom to reduce the risk of shearing off one side
• Embedded magnets (10mm round x 10mm) so I can stick it in place then guide the jack to it
• Cleaned up code
• Added raft for easier printing in nylon

Updates tested! The PTCPE performed beautifully. See my jack stand adapters https://www.thingiverse.com/thing:2948734 for a better example of the PCTPE flexing. The only problem is the magnets need to be stronger.