Again after a delay I would like to continue this topic and hopefully the discussion.
With reference to the post by ulrich1a
https://forum.freecadweb.org/viewtopic. ... 10#p251462
After analyzing I cannot share the perspective ulrich1a
has on the problem, because its too complicated to realise.
In other words I think the problem we are faced in displaying threads in Techdraw, is not a problem of "decorating a surface".
Lets focus the fact that in technical drawings it is not essential
to build a real thread
In contrast to this for a simple approach in Techdraw the main thing is
that threads in technical drawings according to e. g. ISO 6410-1 (Technical drawings; screw threads and threaded parts; simplified representation)
are described in simplified form
My proposal for an easier way in Techdraw could be by means of the already existing functionality bore
in part design wb.
The needed functionality in Techdraw wb must follow the thread manufacturing steps and must be transferred to the programmed bore-parameter mask.
For example following the manufacturing steps for making an inner thread, e.g. M4 thread in a blind hole:
1. step: the core bore of the thread is drilled with classic drill tip angle 118°.
Example: M4 --> here the core diameter is 3,2 mm. The drill depth is e.g. 25 mm
2. step: cutting of thread M4 in core bore is carried out. Related to the existing core bore depth, the depth of thread is 18 mm. The tip is not relevant
So as always in thread manufacturing we receive 2 overlaid cylinders
that are in a fixed relation
For e.g. metric iso threads the values are valid:
M4 Ø core 3,2 Ø thread 4,0
M5 Ø core 4,0 Ø thread 5,0
M6 Ø core 4,8 Ø thread 6,0
M8 Ø core 6,4 Ø thread 8,0
The structural main task is to combine the 2 cylinders
in programming for the preparation of the technical drawing.
I would like to bring up again topics and opinions for discussions and hope that anyone could share this opinion?