"Uni-kun", Japanese Uni (sea urchin) opener (updated)

thingiverse

A 3D model based upon the ubiquitous **"Uni-kun" sea urchin opener favored by Sushi chefs**. Stateside prices for this tool on the internet seems to hover **around $70 while this can be printed for ~$5 worth of plastic**. Since I had no access to the original tool I used as a model pictures of it on the internet. It is not meant to be an exact reproduction of the original tool, but certain features such as its overall shape and length are expected to be close. The **pivot hole has been designed to take a 5/16" diameter bolt**. A **recent update** added spring retainers on each handle to accommodate a compression spring. I used a **2-3/4" x 3/4" OD x 0.062 compression spring** found at my local True Value hardware store. **For those that have already printed the older design**, separate STL files are provided here so you can print just the spring retainers themselves, saving you valuable print time. Just use your favorite glue or epoxy to attach them to the handles. Note that due to slight geometry differences between the two handles that the spring retainers (left and right) are not interchangeable with each other. I've uploaded **five different STL files** of the same design. Two of the STL files represent each of two handle pieces w/the spring retainers while the third STL file is if you'd like to print the entire tool as an "assembled in place" print. (The design incorporates 0.5mm of clearance between their mating surfaces. Please ascertain if that is enough clearance to work for your printer.) The final two STL are the spring retainers (left and right) to glue or epoxy into the handles if you have already printed the older design. Note that I have yet to use this tool so cannot say if it is sufficiently strong enough for the task, but by all appearances it does feel extremely rugged...