Compound angle milling?

Mar 28, 2008 6 Replies

I want to mill a 10* angle on the leading edge of a skid fin for my model boats. The lead angle of the fin is 30* and I need the 10* "wedge" parallel to the water line so the fin doesn't cause lift.



I think there's compund angles involved but I just can't see the setup, here's some pix of what I'm trying to do:



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Here's what it looks like in action:



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The fin is that bit hanging off the right front sponson.



Any ideas?


--Well the two things that come to mind are grinding it freehand (the way surfers make fins) or making a mold with that shape already in it. Neither one is trivial, but it's a whale of a lot easier than trying to mill that kind of shape without a cnc..

=2E..

How about drawing a line on the part parallel to water flow and tilting that line to 10 degrees?

It might be easier to place a 10 degree angle gauge on the line and level the top.

Jim Wilkins

Thanks for the reply's guys, not sure I follow though...

...

How about drawing a line on the part parallel to water flow and tilting that line to 10 degrees?

It might be easier to place a 10 degree angle gauge on the line and level the top.

Jim Wilkins

Is this like a knife edge, or just 10 degrees on one side? By 10 degrees parallel to the waterline, I assume you mean the angle intersecting the waterline is to be 10 degrees included.

"> Is this like a knife edge, or just 10 degrees on one side? By 10 degrees

It's just 10* on one side, a wedge really.

I think I figured it out. If I tilt the head on the mill 30*, set the turn fin up with it's LE parallel to the table then tilt it 10* in the "y" direction, it should work if I cut in the "x" or longitudinal direction.

I'll post a pic. when I get to it tomorrow or Monday...

Here's the setup:

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Now I've got a perfectly flat 10 degree wedge, just what I wanted! :)

Thanks for the help!

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