Punching Holes In Cylinder


I’ve looked at about a dozen different tutorials on how to punch a hole through a cylinder and for the most part I get the process. However… For some reason the results are very inconsistent for me and often result in a broken model. In the sample file I have uploaded there are two cylinders. The one on the left is a cylinder that was created using circles with 24 segments while the one on the right has 96 segments. For the left cylinder, I was able to properly punch holes through using the methods in the various tutorials I’ve found. Generally my steps consisted of creating the main cylinder and then creating the bore cylinders and position them in the proper location. Then I would explode the model, intersect faces and start deleting the centers of the holes out.

For the model on the right and with 96 segments, I would try this same procedure I would usually end up with at least 3 or 4 holes that are consistently broken and I cannot remove the centers because it would end up deleting the interior wall of the cylinder. When I look at the intersected line segments it would appear that some of the segments did not join to create a complete circle. Why this would happen on only some of the cylinders and not the others is beyond me. I would appreciate some expertise on how to do this properly and perhaps maybe a bit of an explanation why the process most people seem to use for a 24 sided circle would fail on a 96 sided circle.

For those wondering why I need 96 sides, I have to export my models to solid works as these are parts that will be milled on a CNC machine. I need a very round and smooth cylinder which the 24 sided circles did not provide. If there’s a better way to doing this than trying to create higher resolution cylinders I am open to it.

Sample.skp (144.1 KB)


Your geometry is too small, scale it up (1000x for simple calculations) and it should work…

Maybe this is a solution for your problem?


Thanks, I’ll give both of these options a try!