roll crimp question

[slopoke]

I want to do some roll crimping on 12ga. slugs on a drill press. How do you hold the rounds secure and straight?

 

[Spacegold]

I used to roll crimp paper 10 ga. shells on the drill press just holding the shell in my hand on the drill press table. It is important to run the crimping spinner at a slow speed so it does not overheat the material or sieze the case.