The advent of low-cost, customizable, additive manufacturing methods of 3D printing offers promise for applications in mechanical rheometry. By taking advantage of the high in-plane resolution of a consumer-grade fused-deposition 3D printer and using solvent welding, we design and manufacture both standard and customized plastic tool geometries suitable for use in mechanical rheometers. In particular, 3D-printed tools can be designed to match available sample volumes of soft materials, and, while these plastic tools can be reused in many cases, they can also be disposable, especially when certain materials can be very difficult to clean. Here, we demonstrate the versatility of this approach by designing and producing a raised annular parallel plate geometry, which offers a more uniform strain field and a higher torque than a standard parallel plate geometry. We also show that customized tool roughness can be directly printed, and we demonstrate that 3D-printed roughened tools can provide a noticeable improvement over smooth metal tools in mechanical rheometry. Overall, selective design and use of consumer-grade 3D printers opens up many exciting directions in mechanical rheometry. (C) 2016 The Society of Rheology.