Hi Harold,
A quick reminder: I have not built a physical prototype, whether out of acrylic or metal. The entire design of the STCM was completed strictly in manuscript form by hand in September 2025 and officially certified in February 2026. I only used a pencil, a compass, a ruler, and a 10-cent coin to layout my sketches on paper.
To remain completely honest with you, I must point out that without the help of an AI to structure the explanations that follow, I would have never known the technical terms to formulate this response. I truly hope these answers make perfect sense given the context of your tests, and if they do not, please let me know as soon as possible so we can figure it out together and correct it!
If your community is experiencing binding issues with your laser-cut acrylic tests, it is a structural rigidity problem. Acrylic flexes too easily under continuous torque, which misaligns the perpendicular dual-axis and creates severe pivot friction, seizing the hub. The STCM requires rigid metal fabrication so the weights can properly apply their forces. If the pivot anchor points, a DM lever arm, or a relay are even slightly out of place or not the correct length, the system will not rotate properly.
Please keep in mind that my original measurements were taken by hand, flat on a table using a standard ruler. They could easily be off by 1 mm for many understandable reasons, which is why thoroughly understanding the geometric logic of drawings 2, 5, 6, and 7 remains critical for your digital adjustments.
The true mechanical foundation is established on Page 6, Figure A. By identifying the center of the two masses, you will find that the nominal distance is 6.5 cm, which dictates DM pivot arms of exactly 3.25 cm. Figures A, B, and C on Page 6 clearly demonstrate this basic principle and its rotational effect. Once this conceptual basis is understood, Page 7 addresses the obvious kinematic binding by introducing the articulated relays. If you understand the reasoning behind this solution on Drawing No. 7, specifically calibrated using the dimensions frozen at the 9 and 3 o'clock positions, the core of the system is mastered, allowing you to establish and apply your own dimensions based on your desired overall diameter. Everything that follows is simply the logical sequence of this foundation.
Finally, on Drawing No. 10 (Ceiling View), please note that each pair of DM has its own independent central axle, positioned side-by-side. On my hand-drawn layout, they are shown very close to one another. Make sure to widen the spacing between these two independent axles in your 3D model to better visualize the structure and prevent any mechanical collision. Furthermore, the rod serving as the axle must allow the DM pivot arms to rotate completely freely, for reasons that are visually obvious when looking at the overall movement of the assembly.
Your 3D software needs to be set up to visualize and differentiate what conventional engineering tools rarely calculate: a mass on the right which, by being pushed away from the center hub, exerts exactly more torque at the center than the left-side mass that stays close to the hub.
To guide your CAD modeling and prevent flawed cuts, use these exact geometric proportions from my drawings:
1. Basic Lever Principle: The baseline radius is 7 cm in my early conceptual drawings (scaling up to 12 cm for torque optimization). Treat this as an overall scaling guide, as the dimensions adapt depending on your build size.
2. Dynamic Guidance (DM) Shift (Drawing No. 7): The strict theoretical center-to-center distance is 4.2 cm, matching the logical 2.1 cm spans on figures A and B.
3. Technical Honesty Note (Figure C): On figure C of Drawing No. 7, j'ai écrit 2.2 cm. This drawing should have logically yielded 2.1 cm, but I refused to forge the data or cheat just to make the numbers match perfectly. I noted down the exact measurement of my hand-drawn layout.
4. Articulated Mechanical Relay & Chain Reaction: This single millimeter deviation on the drawing pushed the relay length to 5.5 cm. If you model it with the clean theoretical value of 2.1 cm for the DM, your horizontal linkage must measure exactly 5.4 cm for its harmonious rotation aiming to eliminate passive suspension and transmit the gravitational difference of these two identical but differently arranged weights to the axle and central pivot.
Hoping this additional information helps ensure the success of your testing, speak soon.
Best regards,
Benoit-Collin