Problem trimming

This is a problem I come across once in a while. Not often, but I tried this file in Rhino 6 and 5, so it’s not a Rhino 6 problem. Tried various cures (rebuild, explode-join, re-align seam etc.), can anyone help? It’s important to me to trim half, because sometimes it’s time consuming to fillet both sides. I did find a work around by trimming before Boolean-differance centers. Still it would be helpful for the future to know why this happens and what the cure is. Cannot trim half once Boolean centers

trim problem after booleen 5.3dm (1.5 MB)

Hello -
Hm - well, all the below still holds as far as cleaning up your modeling process but it now looks to me like running MakeUniform on the cutters may be all you need to make this work…

it looks to me like maybe the problem is in the construction of the inner faces of the repeated parts in the object to be cut. It looks like you’ve created these bt lofting two trimmed edges:

image

In fact as far as I can see, these are parts, in theory, of a cylinder (Same with the outer faces) and unless there is some reason not to, I would always make these as trimmed bits of a cylinder:

image

In fact that whole inner surface could be and I’d say should be, trimmed from a single cylinder:

image

image

I think making these from more exact and simple surfaces will clean up your workflow a lot. I’d say the tapered surfaces could also be cleaned up.
trim problem after boolean_PG 5.3dm (727.2 KB)

-Pascal

Thank you Pascal. The trim worked on my old file when I “Make Uniform” the lofts used to boolean difference the holes. Never used that command before. When I Duped Border to make cutting lines for the bottom from a simple extrusion from a circle, I could not get it to join without naked edges!xxx.3dm (1.0 MB)
. That was the reason for using the duped border lines for the bottom extrusion. I will work on it some more, simplifying things. One more thing , why could I do a simple fillet om my file

and not yours?
Thank you so much for all the help you have given me.

It’s probably that tapered surface - I still don’t like it much - it should also be much simpler.

trim problem after boolean_PG_2.3dm (491.9 KB)

-Pascal