Compound mitre cuts

SketchUp
1

I hope this is the correct place to post this.

I need to create a “duct” for dust collection on my mitre saw. Its a 6 in tall box that has compound mitre cuts on the corner and I am struggling. I have searched for videos on youtube and found things that are close but I can’t get it right.

I have the in side dimensions and material thickness. Top opening is 19" x 10" and the bottom opening is 11.75" x 6.75" and I am using .75 plywood.

I thought I had the angles at 30 and 15 but when I cut them with 45 degree in the corner the angles in the corner is too steep.

if there is a tutorial that would help I would like to learn this for future projects.

3

Looks pretty close. I am confused by the 45.6 vs 49.6

image
image1734×820 16.4 KB

4

I feel like the angles on the ends will be different from the angles on the long sides.

6

inside dimensions. I have a plastic piece for the short end that connects to my dust collection.

8

There’s no need to model the panels with thickness to merely find the miter angles and lengths.
Simply model the exterior Faces only.

There is a (free) plugin which will yield the dihedral angle.
The miter angle = the dihedral angle / 2

Angle Between Planes v1.0 — SketchUp plugin by Clark Bremner

Read the plugin documentation and then experiment with it.
http://sketchucation.com/forums/viewtopic.php?p=137656#p137656

Here’s what it does.
Right click on the common edge of two faces.
The dihedral angle is immediately displayed in the context menu.

Angle Between Planes
Angle Between Planes1472×859 86.3 KB

1 Like
9

Awesome thanks

1 Like