My friend called me to replicate a 1940’s Norton motorcycle bracket.
It connects the motor and transmission.
He is going to transfer the holes, so he needed the outline.
I tried taking a photo and tracing it, but that quickly turned into junk.
So from the sketch I made from the failed photo try, I planned out the points that I would need.
I selected all the tangent points. I should have added a few intermediate points on large arcs.
I put a 1/4 dowel pin in the SP5, eyeball leaned the pin against the taped down bracket and recorded the points.
I tried connecting the dots directly, then offsetting the curve, but that produced curves that were not tangent to each other.
So I added 1/4 dia circles to the points and created a sketch with curves that were tangent to the 1/4 circles. That worked out much better.
I used my old drafting circle templates to get the radii of the bracket curves.
Cut the results in 1/4 hardboard to confirm. I still had some issues, but not too shabby.
I gave him the DXF file which he will send to SendCutSEnd .
It took too much time, but I got a reasonable process out of it.
I need to get a drafting curve template with radii larger than 4"