That’s curious. Is that a bug? I’ve never noticed that before but then I’ve never had any need to measure that sort of thing. Measure from the midpoints of the edges. I think you’ll find those distances match.
At least for my use, that method of drawing a countersink is more than accurate enough. It gets the point across. If someone was going to make the part I drew with the countersink, they are going to use a countersinking bit to recreate that. Even for a 3D printed part, I would machine the countersinks instead of printing them…
My post was in no way meant to be critical of your sketching or woodworking methods. It was more about me learning why the offset tool does this. If you draw this with two concentric circles it works fine.
I agree that this tolerance is small. No woodworker and likely few machinist would ever notice it.
I didn’t take it as a criticism. I can reproduce the result you got. I suppose the difference is that the radius of a circle is measured to the vertices and the offset is measured parallel to the edges. those distances would have to be different, wouldn’t they? I can see there might be some cases where one method makes more sense than the other.
Edited to add: Here’s an explanation of why they’d be different.
I was drawing some countersunk holes today with the Wudworx plugin and went to check the countersink angle. It doesnt appear to be correct. Is anyone else seeing this issue ?
The piece I drilled with Wudworx is on the left, a 5mm hole diameter, 25mm depth with countersink angle of 90deg. The included angle should be 45deg but measures 26.6 deg.
On the right, I used the method described by Dave in this thread with concentric holes 5mm and my desired outside 8mm diameter, then did a move with autofold down using the offset of 1.5mm, the included angle is measured correctly as 45 deg for a total 90 countersink.
Dave,
Thanks for the reply. You confirm seeing the same thing ? Wondering if this is a Mac only issue. Wouldnt be the first time.
Actually I have used Wudworx before for showing countersunk holes for screws but never had a need to measure or include the countersink angle on construction drawings.
If I need to make the exact countersink angle I have the choices shown earlier in this and other threads.
