I designed a soft blow hammer that fits my needs.
Its designed from the ground up but heavily influenced by Mr. MegaTronic THWACK [https://www.printables.com/de/model/46099-thwack](https://www.printables.com/de/model/46099-thwack)
 

The handle is hollow to get the balance right and not have to fiddle with different infills inside one model.
If you have an AMS I recommend using the AMS profile with PLA and PETG as interfacelayer for easy support removal.
ABS might be the best material for the handle part, but PLA is easier to print and sufficient.
With 150g the hammer is pretty substantial.

There is a version with changable TPU caps.
[https://makerworld.com/en/models/520528#profileId-436944](https://makerworld.com/en/models/520528#profileId-436944)