by mattb » Wed Dec 12, 2018 1:10 pm
Here are the initial results of a 3D printed frame tongue to fit the Dynamic cast motor mounts from the 60's. Paul Miller took time to measure and design a tongue and used that program to print a couple. I put one together yesterday and gave it a test
Here is the prototype. It may be better to thicken up the guide hole extension to be flush with the bottom of the tongue body and then it will be stronger and can be sanded to give correct guide height. That would eliminate the step shown on the stock tongue. The tongues are upside down in this picture.
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Fit was correct and all stock parts worked great.
Lighter and more flexible than a stock tongue. I added 4 Dynamic weights and it settled in the track fine. Usually I put a piece of brass underneath to add weight and improve handling. That is the best way to improve all Dynamic chassis. In this case it would also make it more rigid, although flexiblbility didn't seem to be a problem.
I usually put a spacer between guide post and frame hole to move the guide down in the slot. This is not always needed and depends on front wheel size and chassis setup. I think it might be better to make the bottom of the guide extension flush with the bottom of the tongue. Stock tongues have a small offset to the top. By making it flush on the bottom, it would strengthen the guide extension a bit and it could be sanded to make a step and move the guide upward, if needed.
Here's some pix and Paul can weigh in with more info. I am impressed with the whole process and appreciate Paul taking time to experiment with this. I purposely did three wall shots to see if it would break. It held up OK.
Here is the built up chassis with weights attached.
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Here is a brass plate attached as I usually do, which would add weight and rigidity.
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