Advice for drafting/printing an odd, asymmetric plate for a repair?
Hi all, i'm trying to print a replacement back for a vintage porcelain clock. The original is a badly warped piece of mason board or something and i'm trying to get a workable trace of it in fusion360. I took a second jab at it last night, taking a pic of it on my mk3s print plate so i can use the grid to calibrate it as a canvas in f360 and it once again came out stretched in a weird direction. I really wish it could be as easy as just getting one side right then mirroring it but unfortunately its not symmetrical to begin with. Last time it was too wide, this time its too tall and somehow narrow at the bottom.
Any tips before i burn a whole spool on test fits?
RE: Advice for drafting/printing an odd, asymmetric plate for a repair?
This is a tricky problem to get right as there is hidden parallax error in the photographic method. A few things that have helped me when doing this:
1. Lay a scale (metal ruler, preferably a machinist's scale or the like for better precision and as long as you can fit (the longer the scale the less conversion error)) on the surface of the object. This is a far better reference to scale the canvas in Fusion and since you will be tracing the top surface of the object you need the scale in the same plane as that surface. Orient it as precisely as you can along one of the axes of the part for a convenient rotational reference in Fusion as well.
2. Get the camera as far away from the surface of the object as practical, use the zoom function of the camera to "fill" the viewfinder. This is important as the closer the lens is to the object the greater the parallax error due to the object having physical height above the surface.
3. Try to get the lighting as uniform as possible and as directly above the object as practical to avoid shadows around the edges which will make tracing the canvas more difficult.
I hope this is of some help, good luck.
Regards,
Steve
RE: Advice for drafting/printing an odd, asymmetric plate for a repair?
Evan, I work on old clocks and masonite board IMHO is not really vintage.
Anyway, your photo shows the circumference or shape symmetrical enough for the back of a clock, which will not be seen normally.
The only non symmetry is the 3 hanging ? holes.
You can always print this part in 2 pieces, and tape together if your print bed is not large enough.
RE: Advice for drafting/printing an odd, asymmetric plate for a repair?
thanks, i figured it had to be some kind of angled photo. It looks straight on, and my pixel has a gyro kind of thingy when the camera's up that tells you when you're aiming straight-on at the subject, but its definitely not perfect. I'll give these a try tonight
RE: Advice for drafting/printing an odd, asymmetric plate for a repair?
its tricky and it took me some time to notice it myself thinking it was symmetrical but if i stand up the back cover so its resting on the 2 lowest points, the peak of it will be centered but the two left and right-most points are at different heights. Its a strange shape - old clock from the 50s, kind of cartoonish. All else fails maybe i can do the 2 halves thing and just drill the holes where they needs be i suppose.