I quickly modeled a replacement knob for the toolpost release handle on a Knuth DM1000A lathe. Thread is M12-1.75. Dimensions in image.
Print in your choice of oil/heat resistant materials. I printed this one in ABS+GF. We'll see how long it lasts before it breaks. Then it will probably be printed in Nylon.
The author marked this model as their own original creation.