The device in front is a pretty standard tool for slashing dough for baking. I did not like it at all.

The blade sits out in the open and you lose the little sheath that comes with it.
It doesn't give you control. If you want to do a big slash it's fine but if you want to get ornate small cuts it sucks.

So I started trying different designs in the woodshop. So far I like the second from the bottom first. It's better for my hand size. The blade can be stored in the device when not in use. It allows for fine movements where you can control pressure and angle.

The third from the bottom is just large enough to hold the blade inside when not in use.
It's too small for a lot of hands.
It requires complete disassembly to store the blade instead of just tucking it inside after loosening the wing nut. Each time you have to touch a blade increases the hazard.

The top one is a mix between two and three. I made it just a hair too small to allow for the blade to just swing inside but it does offer a wide profile for easy control.

These were all made with scraps (maple, cherry, white oak) and stainless steel nuts and bolts. Sealed with Watco butcher block sealant. Cost each was about $2 for hardware because I went with stainless instead of zinc. Going with zinc would get the cost down to under a dollar but for kitchen use I recommend stainless or brass.

The dough was leftover from a week of pita eating. I'll need to find a use for it other than its current status of experiment fodder.