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THRU, THRU ALL and Continuous Feature

THRU, THRU ALL and Continuous Feature

THRU, THRU ALL and Continuous Feature

(OP)
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

RE: THRU, THRU ALL and Continuous Feature

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: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: THRU, THRU ALL and Continuous Feature

Ditto Kenat.
Out of the box SolidWorks default uses THRU ALL.

Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion

RE: THRU, THRU ALL and Continuous Feature

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.

RE: THRU, THRU ALL and Continuous Feature

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.

RE: THRU, THRU ALL and Continuous Feature

Talk to a machinist, it should never be assumed a hole is THRU or an angle is a right angle.

Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion

RE: THRU, THRU ALL and Continuous Feature

(OP)
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

RE: THRU, THRU ALL and Continuous Feature

14.5-1994 1.8.9

Quote:

Where it is not clear that a hole goes through, the abbreviation THRU follows a dimension

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: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
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RE: THRU, THRU ALL and Continuous Feature

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.

RE: THRU, THRU ALL and Continuous Feature

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.

RE: THRU, THRU ALL and Continuous Feature

(OP)
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

RE: THRU, THRU ALL and Continuous Feature

Link to the Yahoo! group please?

RE: THRU, THRU ALL and Continuous Feature

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

RE: THRU, THRU ALL and Continuous Feature

haha - thanks. :)

RE: THRU, THRU ALL and Continuous Feature

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.

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RE: THRU, THRU ALL and Continuous Feature

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

RE: THRU, THRU ALL and Continuous Feature

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." - Robert Hunter
 

RE: THRU, THRU ALL and Continuous Feature

Does anyone have a view on whether the abbreviation 'THRO' is an acceptable alternative to 'THRU' ?

I notice most people refering to ASME Y14 so just to add another spin ... according to BS8888 there are two points I can glean.
1. One should assume that a hole is 'through' unless specifically shown otherwise. It is however acceptable to use additional 'notes' if the design intent would otherwise be ambiguous.
2. It is strongly advised that the use of abbreviations be kept to a minimum. If necessary they prefer that one should write the word in full to avoid ambiguity. The principal behind this is that a technical drawing should transcend language barriers.

Be interesting to hear you thoughts on my first post!!!
Cheers, Jon

RE: THRU, THRU ALL and Continuous Feature

Jon, I'm pretty sure we used to use THRU back when I was working in the UK.  BS8888 is essentially a compendium of the relevant ISO and similar specs so they'd probably emphasize the language barrier issue more.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: THRU, THRU ALL and Continuous Feature

So that strong advisement for min. abbr. is coming from a BS spec and not thru  ISO or ASME? winky smile

 

RE: THRU, THRU ALL and Continuous Feature

fcsuper,
I would like to know why they didn't just go with CZ (common zone) like the ISO have been doing for years.
Are we really interested in standardization or not?
Frank

RE: THRU, THRU ALL and Continuous Feature

(OP)
:)  I'm not sure.  But ASME and ISO are both lacking in different areas.  It may seem that ASME tends to err on the side of caution from a litigation standpoint and ISO from the standpoint of inspection/quality-systems.  But there's plenty of areas that are good regardless those, which either standard would do well to adopt from the other.  

Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion

&

RE: THRU, THRU ALL and Continuous Feature

Use of the word THRU is redundant because when a hole specifies no depth it is understood to be through.  In situations where hold penetrates a single wall with another wall behind it a section view is mandatory.  I think you'll find that the word THRU is not even defined in Y14.5!
 

Tunalover

RE: THRU, THRU ALL and Continuous Feature

A hole with no depth callout is a through-hole.  In situations where there may be a secondary wall behind the first penetration then a section view is a must.  The word THRU is defined nowhere in ASME Y14.5M-1994.
 

Tunalover

RE: THRU, THRU ALL and Continuous Feature

Cant' argue with that, other than to remind that old habits die hard.  While there may not be an explicit definition for "THRU" in Y14.5, it is used in some examples, at least in the '94 version.

"Good to know you got shoes to wear when you find the floor." - Robert Hunter
 

RE: THRU, THRU ALL and Continuous Feature

Quote (ASME Y14.5-1994 1.8.9):


Where it is not clear that a hole goes through, the abbreviation THRU follows a dimension

Maybe your copy of the standard has a page missing tunalover.  Heck, I already posted this above at 22 Oct 09 11:23 you guys aren't even trying.winky smile

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: THRU, THRU ALL and Continuous Feature

Thanks for that, KENAT.  I see that it is also in the '09 version.

"Good to know you got shoes to wear when you find the floor." - Robert Hunter
 

RE: THRU, THRU ALL and Continuous Feature

(OP)
It is hard to miss specific topic in the ASME standard when just skimming through.  The index of is no help on most searches too.  Maybe this is a good reason to by the PDF version of the standards?

Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion

&

RE: THRU, THRU ALL and Continuous Feature

KENAT-
Good catch.  Thanks for straightening me out.
 

Tunalover

RE: THRU, THRU ALL and Continuous Feature

Per Kenat is how I have always noted thru holes. If the part has another feature in the way of the hole that I'm also going thru, I indicate "Thru All".

Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion

RE: THRU, THRU ALL and Continuous Feature

I didn't find it first look, fcsuper had to point it out to me.

I still haven't been able to find where in 14.5 it says that "A hole with no depth callout is a through-hole" even though I've often heard this said, and used it myself.  

In fact 1.4b kind of implies this wouldn't be the case "...nor assumption of a distance or size is permitted...".

Maybe I'll actually increase my use of 'thru'smile.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

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