attempting to no avail to replicate a trimming sequence with the latest WIP I’ve used often with Rhino 8; don’t know if it’s the geometry, operator, or a unrecognized WIP feature. conceptually I’m attempting to trim a thread surface with a countersink surface; delete the excess thread surface from the trim; and then trim the countersink surface with the remaining thread surface to yield a common edge that can be joined… a slide showing the geometry is included as is a copy of the WIP file.
This worked fine for me after I untrimmed the thread. The trimmed thread end in your file did not intersect with the blue countersunk feature. I’m not expecting it to go through the blue surface once trimmed but in order to trim the blue cone, the boundary needs to be exactly on the blue surface.
You can also do this as a boolean operation if the cone fully contains the end of the untrimmed thread polysurface.
back with continuing “thread” problems; clearly the operator! I’ve previously created a thread surface that closes; can’t figure out which switch is needed or not needed. checked pitch and “thread form”, both 0.03125; ie: 32 threads per inch… nothing in “Help” anyone see or know what I’m doing wrong?
Thanks; sweeping two lines and joining works much better than one!!
new challenge… how do I encourage/force the intersection perimeter of a 10-32 thread surface and a co-axial inverted 45 degree cone surface to close? think the chamfer of drilled and tapped hole; most of have chamfered a tapped hole and know the intersection of the thread form and a counter-sink yields a closed surface…
That said, your illustration looks reasonable. If I boolean subtract a solid cone from either a block with a threaded hole, or a threaded rod, I get a similar intersection. In both cases the resulting objects are closed.
If the spike at the end of the rod is throwing you, that is the correct intersection, however if physically making this we tend to break it off with the tool and/or file it down.
I’m unable to “subtract” the cone surface from the thread surface; the intersection curve doesn’t close as shown in the previous post. the game plan is subtract the cone surface from the thread surface to, subtract the resulting thread surface from the cone surface, and join the differenced thread surface to the upper portion of the differenced cone surface… the only thing required when all is said and done is a “water tight” surface so I can get parts made; the tapped holes will be specified the old fashioned way
If you remove the existing trims from the thread surfaces you will then be able to split them with the cone. However you will then find you are stuck with naked edges along the outer helix.
Rather than go in circles with that construction, I have generated an internal thread cutter using the Boltgen plugin and used that with boolean difference to make threaded holes in a copy of your part. I then scaled up your cone (so that the base doesn’t coincide with the face) and boolean differenced it from your part. You end up with a closed polysurface and no naked edges. You also have roots and crests on the thread which is more realistic, but may not be what you want, of course.
