Drafting Compound Angles 1

[iamerror]

Hello all,

I am new here but have been a lurker for quite sometime, everyone here has been such a great help thanks! I have a question on drafting a compound angle and would like opinions on proper definition. I searched but I could not find my answer in that way, thanks again!

See drawing attached, it's a basic version of what I am trying to do. Assembly will be located with two holes (one round and one diamond pin), a compound angle will be machined with a profile of .020 and an angularity of .010 for refinement, respect to datums B, A, & C.

 

[TheTick]

That's not really a compound angle. It's an auxiliary projection. The projection line ("A-A") is perpendicular to the bend line.

 

[iamerror]

TheTick, thanks for the feedback, yes I agree it is not truly a compound angle my mistake. I'm trying to verify if this is the proper way to define this type of angle.

 

[pylfrm]

iamerror,

The general approach you've taken appears correct. Be aware that the .235 dimension does not actually define a relationship between the toleranced surface and the datum features though. It refers to an edge only.

You might be better off dimensioning between the axis of datum feature B and the theoretical intersection of datum feature A and the toleranced surface. This could perhaps be shown more clearly if the cutting plane for section A-A were coincident with the axis of datum feature B, and the direction of view reversed.

Also, are you sure about the order of precedence for the datum features? I'd be surprised if A isn't a more suitable primary datum feature from a functional standpoint. It mounts against the surface of another plate with the pins, correct?


pylfrm

 

[iamerror]

pylfrm,

Thanks for the information, good points on dimension ".235" and the datum feature precedence. Datum feature A does in fact contact a mounting surface and is located by two pins.

As for dimensioning the relationship for the toleranced surface see attachment, is this the direction you are talking about?

 

[pylfrm]

iamerror,

Yes, that's about what I had in mind. You still need the 6.738° dimension though, or at least something to similar to serve the same purpose. Also, what you now have dimensioned as 1.780 looks like it should actually be .110 or so.


pylfrm

 

[iamerror]

pylfrm,

Thanks for the information and feedback. Yes of course, the basic angle will be added and the "1.780" was not true and just a representation from the real drawing.

 

[iamerror]

Hello all,

I am back to revisiting this concept to gasp. Attached is one example of a defined angled on the assembly, the first basic angle is from the edge and the second is an aux view, wondering if this looks understandable to you guys. Thanks again!

 

[pylfrm]

iamerror,

That looks fairly understandable. It's a little hard to see what's going on with the linear dimension in section A-A because the angle is so close to 90 degrees, but I guess the "ORIGIN" note is intended to clarify that. Not much else you can do unless you want to exaggerate angles on the drawing.

One possible improvement would be to have the angular dimension in the front view relate to a vertical line connecting datum features B and C, instead of the current horizontal line.


pylfrm

 

[iamerror]

pylfrm,

Thanks again for your feedback!