On Tue, Aug 4, 2020 at 7:11 AM Gene Heskett <ghesk...@shentel.net> wrote:
> On Tuesday 04 August 2020 05:23:49 andy pugh wrote: > > > On Tue, 4 Aug 2020 at 09:49, Gene Heskett <ghesk...@shentel.net> wrote: > > > And the > > > hole size isn't shown in freecad, or I don't know how to display it. > > > > You might need to measure it. As it is STL that will end up being > > vertex-to-vertex so may take a few attempts to find the maximum. > > In fact that could be part of the problem, STL will by its nature tend > > to shrink concave shapes. How many facets make up the bore? > > Freecad doesn't show me that from the step file input either. > Yes, the CAD file (.step file) models the hole with a circle. Only after you output the part as an STL, is the circle converted to a polygon. STL files only have straight lines, no curves. To see how many sides, you need to look at the STL file. If there are few enough sides on the polygon to count by eye then it is a problem. The software SHOULD choose the number of sides such that the error in approximating a circle is below some specified tolerance like 0.001mm or whatever. When Fusion360 exports to STL there is some fine control over the process and I can set the allowed errors. I assume your CAD system has this too. It might default to something you don't want. I'd check this but I doubt the default is unreasonable. Likey the problem is shrinkage, And the unavoidable problem of inside (concave) surfaces having too much plastic As said, boring the hole is the best option if you intend to press-fit a bearing but likely sandpapering the hole is good enough Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
