Break sharp edges

[UchidaDS]

What do you call this? Break sharp edges? It is a round part.

Okay, if it is break sharp corner and I specify max. .010, is the final dimension be
1. Dia. 8.638" -(2X .010, consider reach to maximum)+/-.005"?
2. OR 8.638"+/-.005" will be the final dimension?
Consider the default tolerance is +/-.005"
using ASME Y14.5-1994.

 

[drawoh]

UchidaDS,

Your standard drawing note should state that sharp edges are to be removed. The machine shop will file your edges down. My standard drawing mote specifies the maximum radius. The minimum is not important to me.

You have a tolerancing issue. You need a profile tolerance on the 45[°][ ]face. The diameter and angle should be basic dimensions. A tolerance on the Ø8.638 dimension is useless.

--
JHG

 

[ctopher]

You need to consider which final dimension you want.
Is it "8.638"+/-.005" ?
If this is what you want, adding the note "break sharp edges" may get you a dim less than 8.633.
If you need this dim, remove the "MAX .010", and "break sharp edges" notes.

Chris, CSWA
SolidWorks 14
ctopher's home
SolidWorks Legion

 

[UchidaDS]

If 8.638"+/-.005" is what I want, and it is allowed to have a range of .002" to .010" vertical wall, how should I call this out in the drawing?

To drawoh: if the machine shop file it down per your note in the drawing, what would be the final dimension?
To ctopher: do you mean just leave it as it is, no note at all?


Thanks for the input!

 

[ewh]

I agree with Chris... if you need to maintain Ø8.638, you either need to note on the drawing that it is a sharp corner or specifically dimension the height of the "edge break". If "SHARP CORNER" is added to the first example, either method will work.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[UchidaDS]

ewh: do you mean if I indicate ".010 max edge break" should be good enough and the final dimension will be 8.638"+/-.005"?

 

[ewh]

Yes... 8.638 ±.005 is a drawing requirement, whatever the size of the edge break.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[ctopher]

I agree with ewh last comment.

Chris, CSWA
SolidWorks 14
ctopher's home
SolidWorks Legion

 

[JNieman]

I would draw it with the 8.638±.005. I would draw the 45d angle such that it stops short of a sharp corner, with the 'vertical' wall drawn. I would dimension the vertical wall .002-.010. The 45d does not have a minor diameter on the drawing, so I assume it's unimportant. I wouldn't dimension "break sharp corners" or any other such note, and let the .002-.010 do the work. I would examine just how important the .002-.010 is, though, and open that up as much as functionally allowable.

My two cents.

_________________________________________
Engineer, Precision Manufacturing Job Shop
Tool & Die, Aerospace, Defense, Medical, Agricultural, Firearms

NX8.0, Solidworks 2014, AutoCAD LT, Autocad Plant 3D 2013, Enovia DMUv5

 

[CheckerHater]

There always is the last resort - verbal note.

Makers of Flat head screws use it just fine

 

[drawoh]

UchidaDS,

The standard way for a machinist to break sharp edges is with a file. This is not an accurate process. Unless you have a requirement for an accurate edge, you should not call up an accurate edge. GD&T profile, angle and run-out FCFs will control your angled face, and allow the machinist to break your sharp edge in thirty seconds, with a file.

If you actually need the accurate diameter, then you need to specify the geometry of the "sharp" edge.

--
JHG

 

[ewh]

... which is why I suggested adding the "SHARP CORNER" note. Better have gloves handy!


“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV