A crinkle cutter like this one is really nice for pickle slices. The crinkle cut, like in store-bought hamburger pickle chips, seems to add some extra texture that makes them seem crisper.

Some other tips for crisper sliced pickles:
1. Pickle Crisp. Add it to each jar before filling.
2. Add a bay leaf to each jar. The tannins help crispness.
3. After slicing, put the chips in a colander, toss with some salt, and put in the fridge over a larger bowl for ten minutes or so. The salt will draw water out of the pickles, and the fridge chills them. Both help with crispness.