Hands-free Forearm Deadbolt Turn

Deadbolt locks are another door feature that require hands to operate. This project log discusses a 3D printed hack that allows you to turn the deadbolt lever with your forearm. This design was developed in response to the Covid-19 pandemic. Any opportunity to avoid touching a shared surface in a public space with your hands is an opportunity to prevent the spread of the disease.

The greatest challenge of this hack was designing around the large variation in deadbolt geometries. Deadbolt levers have different widths, heights, and lengths. Some are located in the middle of the deadbolt cover plate while others are offset. Because of all the geometry variations I wasn't able to develop a universal forearm deadbolt turn design. This design will likely only fit one deadbolt design.

Two cutouts on the face of the rotating disk to fit the user's forearm for right handed and left handed motions. The deadbolt lever is visible through the assembly so the user can see it's orientation and determine if the door is locked.

Supplies

• a 3D printer capable of printing a part of size 50x120x80mm (LxWxH)
• two large 19x92.7mm (WxL) damage-free wall hanging adhesive strips, rated to hold 5lb
• two M4x16mm button head screws
• two M4 nylock nuts
• petroleum jelly

Step 1: Check If It Will Fit Your Deadbolt

Use the attached images and .step solid model file to determine if the hands-free deadbolt forearm turn design will fit your deadbolt.

Step 2: 3D Print the Parts

STL files for 3D printing the disk and ring parts are attached. Use 0.2mm layer height, 30% infill, 0.6mm wall thickness, and disable support material. Orient the parts on the print bed according to the images of this step. Total print time for all three parts is five and a half hours.

Use a knife to deburr any sharp edges on the 3D printed parts.

Step 3: Assembly

Apply petroleum jelly to the contact surfaces between the disk and the ring halfs. Connect the two rings around the disk with the M4 screws and nylock nuts. Attach the adhesive wall-hanging strips to the bottom of the ring half as shown in the image. Position the assembly over the dead bolt and secure it to the door with the adhesive stirps.

Step 4: Hands-free Deadbolt Turning Achieved!!

Never use your hands to turn the deadbolt again!