Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations Danlap on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

THRU, THRU ALL and Continuous Feature 1

Status
Not open for further replies.
fcsuper

fcsuper

Mechanical
Apr 20, 2006
2,204
I recently asked this quest in the Y14.5 yahoo group and got some interesting answers. Here's the question: I was just curious in seeing what is currently being done by others with the use of "THRU" on cut features. When is it necessary (if at all). What is the difference between "THRU" (whether necessary or not) and "THRU ALL". And, has anyone starting useing the boxed CF symbol (continuous feature) from ASME Y14.5-2009 (and how)?

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
 
Replies continue below

Recommended for you

Sort by date Sort by votes
THRU - I'd say necessary when it's not otherwise obivious that the cut/hole goes thru the entire part. I'm perhaps a bit generous in my use but having been the idiot searching a drawing for the hole depth only to finally realize it was a thru hole I use it a lot. So even if I have a top and bottom view of a part which hence shows both sides of the hole I still tend to add THRU, even though technically it's not needed as it is clear from the drawn geomery.

To me THRU, unless qualified, means through the entire part. Occasionally I've seen it qualified with 'THRU ONE WALL' or similar but don't like this, I prefer to show a section that explicitly defines such matters. As such THRU ALL is not something I think I've ever used, if in doubt I'll show a section.

Not using 2009 yet. I could have sworn I'd seen THRU in 14.5-1994 but I can't find it now.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
Upvote 0 Downvote
That's it, and obviously I think the way I use it complies.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
Upvote 0 Downvote
I think the CF symbol is used to show the extent of an interrupted datum or geometrically controlled feature as a single entity. I've used it in an example in some drawings for a class.

So, suppose you have a shaft with a radial groove in it for an o-ring. If the shaft OD is a datum feature or geometrically controlled surface, the CF symbol shows that the datum feature or geometrically controlled surface is of a length that's as if the radial groove were not there. There's an example in the standard. I don't have it in front of me at the moment.

It's doubtbful that it's a proper substitute for "Thru one wall" for "Thru All" in a designation for a hole.
 
Upvote 0 Downvote
In my opinion, use of THRU, should be rare. In any view, as long as there are no lines or features which indicate otherwise, a hole should be considered THRU. Just like how right angles are implied to be 90°, so too should any feature be considered THRU, U.O.S.

But where I work now, it's common practice to indicate THRU where a depth would normally be in the hole note.
 
Upvote 0 Downvote
Well, if you call out ASME Y14.5, you can safely assume a right angle (within the specified tol on the drawing). But I'm not sure it is save to assume that a hole is through. The standard doesn't actually say that it is through unless otherwise specified. It simply says to use THRU when it is not clear otherwise.

As for CF, I'm noting the wording in Y14.5-2009, and it doesn't use the term "interrupted" at all. It only states that multiple features are treated as continuous. This is why I'm looking into how others are reading this.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
 
Upvote 0 Downvote
14.5-1994 1.8.9
Where it is not clear that a hole goes through, the abbreviation THRU follows a dimension
Click to expand...

As far as I'm aware it doesn't say to assume THRU unless otherwise specified. If it did then why would it have the above statement? However if ModulusCT or someone can tell me where it says that I'm willing to learn.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
Upvote 0 Downvote
If it's not safe to assume THRU on a hole, what do you assume if you should come across a print where no thread depth is specified?

I guess you might just throw that print in the trash.

This is a supposition on my part. Maybe due to a lack of understanding of the standard. But the standard says, "Where it is not clear that a hole goes through..." and the example (fig. 1-34) shows a hole with a diameter symbol and no depth information next to it (upper left). To me, this says that a hole CAN be assumed to be thru as long as it's depth is clear inferred in the view. Any question, perhaps due to other features on a part, and specifying THRU is the right thing to do.
 
Upvote 0 Downvote
I don't see any way to edit my post...

My thoughts got truncated previously.

What I wanted to say was, when reading the spec, the language used there ("Where it is not clear that a hole goes through...") seems to indicate that there is definitely a situation where it could be clear that a hole goes through. If not, than I think it would have been worded differently.
 
Upvote 0 Downvote
To mean, "THRU" should be used consistantly. There doesn't appear to be consistant use or understanding of it from the standard. However, I guess maybe it doesn't need to be all that consistant since we don't say "For entire part" or overall dims of a block because the drawing is clear enough.

Hey, I'm getting some interesting comments about CONTINUOUS FEATURE (or CF) on the Y14.5 Yahoo! group board. Anyone with thoughts about it here?

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
 
Upvote 0 Downvote
Upvote 0 Downvote
I've always interpreted "Thru" to mean that it is cut until the hole reaches a different piece or air. So a "Thru" hole in the side of square tubing would indicate a single wall only. "Thru all" to me indicates that the hole should continue until there are no more pieces left. So "thru all" would indicate that the hole goes through both walls, along with anything else beyond the tubing.

Even in cases where the holes could not be practically drilled in a single operation. If I had a set of studs for a building and indicated a hole "thru all" in the side of the studs, I would interpret that to mean a hole thru each stud through the whole length of the wall (or however many of the studs appear on the drawing indicating the hole).

However, my company doesn't reference any standards and I'm not familar with them. I can't say why that is how I interpret "thru" and "thru all".

-- MechEng2005
 
Upvote 0 Downvote
The varying interpretations of THRU, THRU X WALLS, THRU ALL is why if in doubt I like to add a section.

If it's a simple hole through solid material with no cavities etc then I'll use THRU. However, if there are walls/cavities I'll tend to add a section so it's unambiguous.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
Upvote 0 Downvote
MechEng2005,

For what it's worth, I have always used the same interpretation as you described.

Joe
SW Office 2008 SP5.0
P4 3.0Ghz 3GB
ATI FireGL X1
 
Upvote 0 Downvote
The problem with that is using it that way without an "official" definition.
Taken literally (as most info on a dwg usually is) THRU means totally through the part, not just until you hit air. Thus THRU ONE WALL and other variations are often used.
When in doubt, draw it out.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

jnelson33
  • Locked
  • Question
Internal Planar Continuous Feature 2
Replies
6
Views
259
Burunduk
Burunduk
supergee
  • Question
threaded hole depth feature of size?
Replies
16
Views
4K
Burunduk
Burunduk
CTengIS
  • Locked
  • Question
Irregular Feature Of Size as Datum Feature on CMM
2
Replies
20
Views
8K
CTengIS
CTengIS
jassco
  • Question
How to use profile of surface feature control frame to control max. protrusion?
Replies
15
Views
3K
mfgenggear
mfgenggear
Gaganaut06
  • Question
How to properly show compound angles of a feature using GD&T?
Replies
9
Views
4K
jassco
jassco

Part and Inventory Search

Sponsor

Back
Top Bottom