Radius Gauge (RadGauge)

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🌀 RadGauge – Radius Measurement Tool

Radgauge is an innovative device designed to quickly and accurately measure the radius of a curved surface. Currently, various designs are available depending on the measurement range and function, and the characteristics of each design can be checked in the table below. 

(Click on the letters in the table to go to the page where you can print the design.)

RadGauge Family

RadGauge NANO is ready for those who need to measure inner corner radius or want to carry everywhere.

RadGauge MEGA is ready for those who need to measure  larger radius.

RadGauge GIGA is ready for those who need to measure even larger radius.

For those seeking even higher precision, the Radgauge-X is available. Each component is tightly packed and uses a bearing.

The RadGauge-Dual is a unique device that can measure both outer and inner radii up to 50 mm with a 1:1 linear scale.

If you love old games, or something cute for keyring, R-MAN is ready for you.

🔧 How It Works

RadGauge starts measuring from the 50mm mark.
When the arm is pressed against a curved surface, it rotates inward, which in turn drives an internal gear.
This gear is connected to a dial, where a pointer moves to indicate the measured radius.

After measuring, the pointer holds its position so you can bring the device up to eye level to check the result.
A reset button on the back returns the arm to its initial position (50mm) for the next measurement.

I initially considered an auto-initialization feature using a spring, but decided against it as I thought it might actually be a hindrance to accurate readings after measurements.

📏 Specifications

• Measuring range: R1mm to R50mm
• Scale interval: 1mm (What you read is Radius.. no calculation necessary. The scale is enlarged to a larger scale than the actual scale for much better readability.)
• Mechanism: Sliding arm + gear-driven dial
• Form factor: Compact, one-handed operation

• Reset method: Manual rear-button reset

   

📐 On Accuracy

You probably think that card gauges are the most accurate. That's true, but only if they match the card you're using, such as 5mm, 13mm, etc. The advantage of measuring with a scale is that you can estimate a more accurate number by reading between the scale marks, such as 5.5mm, 12.3mm, etc. This device allows you to do just that. Plus, the scale marks are spaced farther apart than the actual distance, making it even easier to measure.

The gears and scales are mathematically calculated and designed to minimize assembly tolerances and minimize measurement errors. However, due to the nature of 3D printing, there may be measurement errors depending on the quality of the output. But you will be amazed at the high accuracy.

If you are not satisfied with the accuracy of this model, I recommend the RadGauge-X, which uses a bearing and guide spring system to improve measurement precision.(CLICK)

✔ Before print this

Since this model is a measuring tool, the tolerance is quite tight (0.1mm). Please make sure to use sufficiently dry filament, as you may experience difficulties in assembly if you use filament that is not sufficiently dry.

If the build plate has insufficient adhesion, the scale may not print accurately. (The scale will be printed on the first layer first.)

✔ Assemble layout. (Important)- Super easy and quick assemble.

Assemble at 50mm measure setting

After aligning the parts as shown below, place the front cover horizontally in the correct position, cover it with something wide and solid like a ruler, and press firmly to allow easy and accurate assembly without damaging the parts.

1. General Licensing Statement

This model is copyrighted and its commercial use is strictly prohibited.
This falls under the Non-Commercial (NC) condition of the Creative Commons license.

2. Specific Prohibition on Reproduction Services

PROHIBITION OF PRINTING SERVICES: Providing this model file to any third party for the purpose of paid reproduction (printing) is strictly prohibited.
PERSONAL USE ONLY: All reproduction must be conducted solely on the end-user's personally owned 3D printer.
This license condition forbids the use of printing services, even for a single personal copy.

⚠️ Official Notice Regarding RadianLab™ Model
This model is exclusively manufactured and distributed under the RadianLab™ brand.

The unauthorized sale of this product by any other individual or entity is strictly prohibited and constitutes a violation of my brand rights. I require that any instances of unauthorized distribution or sales be reported to me immediately.

Product Information:

While the products currently sold maintain the fundamental design, they incorporate additional proprietary structures engineered for superior accuracy and usability (user experience). Furthermore, every unit undergoes a rigorous quality control inspection before being offered for sale.

🔬 Measurement Test

This 3d printed design(Butterfly four Cups) has 80mm Diameter… means Accurate.

This is the model I used for testing while designing the RadGauge series.
Test the accuracy of your RadGauge model. (Click)

Thankfully, many people have uploaded various print profiles. However, please note that only the profiles I provide include the most recent and updated models.

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12/22/2025 Model Update

Modified the modeling and profile to ensure cleaner printing of the scale and text.

11/12/2025 Model Update

1. For better visibility, the indicator was changed from a fan-shaped to a pointed needle shape.
2. The indicator's rotation axis was modified to maintain proper pressure.
3. The number size on the scale was enlarged.
4. Assembly tolerances were adjusted.

5. The gear meshing tolerances were revised.

6/19/2025 Model Update

1. Adjust the profile so that the scale and characters are printed more clearly. 

2. Change the triangle pointer to a straight line.

6/15/2025 Model Update

If this update is well-received, I plan to reflect it in the MEGA version as well. So give me your feed back.

1. Reduced the number of parts from 5 to 4. (Made the gear and pointer into one part.

2. Made the pointer symmetrical.(To prevent the pointer from going out of range and for visual stability.)

3. Changed the model of the scale part. (When changing the pointer from positive to negative, the height of the graduation corners was lowered to prevent misreading due to height difference.)

4. Added scales for measuring the length of the right angle corners on the back panel. (Why not?)

5. Made some modeling modifications for smooth movement.

6/12/2025 Model Update 

Updates for improved precision
1. Gear alignment adjustment
2. Tolerance adjustment
3. Scale adjustment
4. Internal chamfer for precise operation

For clear text printing, the multicolor models have the character engraving set very shallow. (At the profile for AMS)
In addition, external character positions have been changed.

6/10/2025 Model Update

For better readability of the scale, the direction in which the scale increases has been reversed.

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Hope you Enjoy this model.

As always, I welcome your feedback.

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