Holes angled to normal

jonathan_mead

I'm trying to draw a cylinder head for a small single cylinder engine. The hole for the spark plug needs to be drilled at an angle of 15 degrees from vertical through the head. I have the position where the hole needs to end up in the combustion chamber side, and need to bore through to the topside of the head.I have spent the past three hours trying to find a way to do this. Can anyone help? 

øyvind_kaurstad

Something like this:



What I did, was first to draw a sketch on the top plane, where I included two construction lines that intersect where the hole should end up (the bottom here being the combustion chamber side). This circle was then extruded to make the solid that represents the cylinder head. Then I made a line angle plane (which is 15 degrees from the plane of the bottom of the cylinder head) from one of the construction lines, and on this plane I drew a circle with the hole diameter, constraining the center point of the circle to be coincident with both of the construction lines. After that I did a extrude remove (though all in both directions) to make the hole.

Please note that the hole is only angled in one direction here (and I also placed it oddly off-center just to show that it can be anywhere). You will of course also want it to be counterbored, but I'll leave it up to you to figure out how.

øyvind_kaurstad

Something like this:



What I did, was first to draw a sketch on the top plane, where I included two construction lines that intersect where the hole should end up (the bottom here being the combustion chamber side). This circle was then extruded to make the solid that represents the cylinder head. Then I made a line angle plane (which is 15 degrees from the plane of the bottom of the cylinder head) from one of the construction lines, and on this plane I drew a circle with the hole diameter, constraining the center point of the circle to be coincident with both of the construction lines. After that I did a extrude remove (though all in both directions) to make the hole.

Please note that the hole is only angled in one direction here (and I also placed it oddly off-center just to show that it can be anywhere). You will of course also want it to be counterbored, but I'll leave it up to you to figure out how.

jonathan_mead

Thank you very much for taking the time to reply. It worked perfectly once I'd figured out how to put a construction line in the right place to align the new plane at 15 degrees to the bottom face of the head. I then was able to construct a second plane parallel to the first but above the head and extrude down the other way to provide a recess for the threaded section of the plug. It still needs some tidying up, but the principle seems to work.

jakeramsley

Another option that fits in with the hole workflow is to use a 'Move face' command after with a rotation.

1. On the point you want to create a hole, add a construction line that goes through it to be used as the axis of rotation of the hole.


2. Make your hole as your normally would and see that it is created without the angle.


3. Turn on the visibility of the sketch you used to make the hole.  Start a 'Move face' command.  Change the type to be rotation, select all of the faces of the hole as the faces to rotate, and then select the construction line as the axis of rotation.  This will cause the hole to be angled at whatever value is entered.