Unofficial gripper modification based on the original NormaCore Parallel Jaw Gripper.
This is not an official NormaCore design. It is a personal modification of the original gripper developed by NormaCore.
This version keeps the general concept of the original parallel jaw gripper, but introduces a more modular mechanical design focused on easier 3D printing, faster iteration and interchangeable jaws.
The gripper was redesigned using Onshape, where the original concept was adapted into a modular assembly with separate printable parts, a larger jaw support base and interchangeable jaw interfaces.
Update: I have created a new adapter for this gripper that is compatible with the custom flexible jaws generated using FingerMod.
This adapter allows the modular gripper to use the flexible jaw geometries generated by the FingerMod web tool without redesigning the complete gripper. The adapter connects the generated flexible jaws to the existing interchangeable jaw interface.
The new adapter was integrated into the CAD assembly and is provided in both STL and STEP formats.
You can generate compatible flexible jaw geometries here:
The following image shows the redesigned gripper integrated into the robot assembly in Onshape.
One of the main modifications I made was to divide the gripper into several parts instead of printing the complete body as a single piece.
Printing the entire gripper body was relatively expensive in terms of printing time and material. The geometry also included several overhanging areas that required supports, which increased the total printing time and made the manufacturing process less practical when testing different versions.
By separating the gripper into different components, it is possible to reduce the amount of material and supports required for each print, simplify the printing process and replace only the part that needs to be modified.
This redesign also made it possible to increase the size of the base that supports the jaws, providing a larger and more robust mounting area.
Another important modification was the introduction of interchangeable jaws.
In the original type of integrated design, changing the geometry of the gripping surface can require printing a large part of the gripper again. In this version, the jaw is an independent component that can be removed and replaced without reprinting the complete gripper body.
This makes it possible to quickly create different jaw geometries depending on the manipulation task.
For example, the gripper can use:
- Flexible jaws
- Rigid jaws
- Short jaws
- Long jaws
- Narrow jaws
- Wide jaws
- Curved gripping surfaces
- Textured gripping surfaces
- Task-specific jaws for particular objects
This approach makes the gripper more modular and allows the end-effector to be adapted to different objects without modifying the complete mechanical structure.
The modular jaw system requires M3 threaded inserts for plastic. The inserts used for this design are available here:
A total of 8 threaded inserts are required:
- 6 × M3 threaded inserts installed in the 4.4 mm diameter holes of
Gripper_Jaw_v2. These inserts are used to secure the interchangeable jaws to the gripper jaw assembly. - 2 × M3 threaded inserts installed in
Gripper_Base_Motorfor the motor-side mounting points.
The six inserts in Gripper_Jaw_v2 allow the interchangeable jaw modules to be mounted and removed repeatedly without threading directly into the printed plastic. This makes it easier to change between flexible, rigid or task-specific jaw designs.
Important: The holes intended for these inserts have a diameter of 4.4 mm. Check the dimensions of the inserts you use before installation, especially if you replace the linked part with a different M3 insert model.
The modular design was mainly introduced to improve the manufacturing and prototyping process.
Compared with printing the complete gripper body as a single component, this design provides several advantages:
- Reduced printing time for design iterations
- Less support material
- Easier replacement of damaged parts
- Faster testing of new jaw geometries
- Lower material consumption when modifying only one component
- Larger jaw support base
- Easier maintenance
- More flexibility for experimental manipulation tasks
The idea behind the design is simple:
Gripper body
|
+---- Jaw interface
|
+---- Flexible jaw
+---- Rigid jaw
+---- Short jaw
+---- Narrow jaw
+---- Custom jaw
Instead of redesigning and printing the full gripper for every new task, only the jaw geometry needs to be modified.
The mechanical redesign was carried out using Onshape. The CAD assembly was reorganized so that the gripper body, jaw base, jaw interface and replaceable jaws can be modified independently.
This makes it easier to modify individual components, create new jaw geometries for specific manipulation tasks, export only the parts that need to be printed and maintain editable STEP models for future modifications.
The STL files are ready for 3D printing:
- CameraMount_square32mm.stl
- Gripper_Base_Motor.stl
- Gripper_Base_Jaw.stl
- Gripper_Jaw_v2.stl
- Flex_Jaw.stl
- Flex_Jaw_1.stl
- flex_jaw_mount.stl
You can also browse the complete STL directory.
Editable STEP models are included for further modification or import into CAD software:
You can also browse the complete STEP directory.
A demonstration video of the gripper is available on YouTube:
This modification is mainly intended for robotics research, prototyping and manipulation experiments where the geometry or mechanical properties of the contact surface may need to change frequently.
The interchangeable jaw concept is especially useful when testing manipulation of objects with different:
- Sizes
- Shapes
- Surface materials
- Rigidity
- Fragility
- Contact requirements
normacore-modified-gripper/
├── README.md
├── images/
│ ├── gripper_onshape_assembly.png
│ ├── gripper_original_style.png
│ ├── gripper_interchangeable_jaws.png
│ ├── gripper_modular_body.png
│ └── so101_flex_adapter_fingermod.png
├── stl/
│ ├── CameraMount_square32mm.stl
│ ├── Gripper_Base_Motor.stl
│ ├── Gripper_Base_Jaw.stl
│ ├── Gripper_Jaw_v2.stl
│ ├── Flex_Jaw.stl
│ ├── Flex_Jaw_1.stl
│ ├── flex_jaw_mount.stl
│ └── SO-101-Flex-Base.stl
├── step/
│ ├── Lineal_Gripper_v2.2.step
│ ├── Lineal_Gripper_v2.2_Flex.step
│ └── Lineal_Gripper_v2.2a.step
└── Videos/
└── Pinguibot.mp4
This is an unofficial gripper modification.
The design presented here is a personal modification derived from the original NormaCore Parallel Jaw Gripper concept. It is not an official NormaCore release and is not maintained or endorsed by the NormaCore project.
Original project:
- NormaCore repository: https://github.com/norma-core/norma-core
- Original Parallel Jaw Gripper: https://github.com/norma-core/norma-core/tree/main/hardware/pgripper
Please refer to the original NormaCore repository for the original design, documentation and licensing information.
Original gripper design and project: NormaCore.
This repository contains an unofficial redesign created in Onshape, focused on modular construction, easier 3D printing and interchangeable jaws for rapid prototyping and robotics experiments.