Help Me Understand Some Geometry....

[glencandle]

Backstory: I'm an artist, not an engineer, and I need some help understanding this:

I want to cut a small channel (1/64") into my part, with a 1/32" diameter fillet in the corner.  When I draft this manually all is well except that where the channel 'bends' it gets wider (3/128").  I don't want this.

I know I can adjust this manually, but as I seem to encounter this kind of thing from time to time I would rather understand the math so I can approach this problem with some precision as my skill evolves.  

Cheers.

[glencandle · Accepted solution]

Never mind I figured it out.  And since I can't delete the question (I still can't figure out why Autodesk doesn't allow us to delete our own posts!), here is the answer:

The inner radius needs to the diameter of the outer radius, minus the width of the channel.  In this case the inner radius needs to be 1/64" to maintain the same sized channel throughout the bend.

Cheers.

[davebYYPCU]

Yep, both radii should have the same centre point.

Might help...

[johnptc314159]

FYI

for clarity i like to see circles 🙂

[johnptc314159]

oops

[glencandle]

Ooh I like this. I’ve never sketched this way but it definitely helps. Thanks for the tip!