Help with D1.1 2010 Figure 5.2

Date 02-10-2013 00:12 Edited 02-10-2013 00:15

Help! I’m not understanding D1.1 2010 figure 5.2

D1.1 2010 Figure 5.2, Optional Method For Making Corner Radius, I understand the top tangent line and the 3/8” radius on the access hole. I don’t understand the bottom tangent line intersecting the radius line, because if I go to:

D1.1 2010 Clause 5.17 “Weld access holes shall provide a smooth transition that does not cut past the points of tangency between adjacent surfaces….”

Then I flip pages to:
D1.1 2010 Figure 5.2, OPTIONAL METHOD FOR MAKING CORNER RADIUS. There is a statement “NEED NOT BE TANGENT”

Would someone "splain" to me what I’m reading. :cry:

Or do I go by the Figure 5.2 drawing ?

Thanking all, in advance for the help that I know is coming. :smile:

By newinsp (**)

Date 02-13-2013 14:19

Easy one. I've done hundreds of these in shipbuilding. The optional method gives a mechanically perfect (smooth) radius. Just as the image of the optional method shows, the bottom cut line is coming from within, or inside, the radius.

The whole point of not cutting beyond (below, or outside) the point of tangency is to avoid creating what we called a 'stress riser', a place for 'tearing' to start. We had 'tearing' problems from a couple of re-powered vessels. I worked at a backwards yard, but we did learn some things there--the hard way.

Not sure if I'm 'splainin' it correctly, so I'll attach a drawing. It just so happens that I'm studying another code that has images of this very thing.

Attachment: PointofTangency.jpg - Point of Tangency (162k)

By jdrmmr

Date 02-13-2013 15:11

new,
You did a wonderful job of 'splainin'.

I guess I was hung up on the “does not cut past the points of tangency” in clause 5.17 and didn’t read the “past” until seeing your sketch of different bad ways to cope.

This site is amazing and a wonderful learning tool.

Thanks for taking the time to teach.

By jwright650 (*****)

Date 02-13-2013 15:13

One of the ideas is to keep your extra cut over in the wasted material and not leave that point of tangency in the material to remain(as was splain'd)

By welderbrent (*****)

Date 02-13-2013 17:37

I would agree, he did great. I would like to also refer you to the commentary for section 5. Look towards the back at the Figure C-5.2 examples of acceptable alternatives when cutting and grinding copes as well as Figure C-5.1 examples of Unacceptable reentrant corners. Some of the pics are basically the same as 'new' attached.

Have a Great Day, Brent

By newinsp (**)

Date 02-13-2013 14:34

We would also drill a hole at each end of a crack before beveling and welding it up. This would be applying the same principal.