Originally Posted by Kebowers

Like pictures. You obviously thought a lot about how to make this tool. Only suggestion is to use a much shallower 'groove' or thicker bar stock. It looks like you have a lot less than 50% of original thickness left in the groove. A better solution is to add additional thickness to center section of the bar stock so the spring is centered by the 'raised portion' rather than a groove.

There is tremendous energy stored in the compressed spring.