×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Thru To Bore Note

Thru To Bore Note

Thru To Bore Note

(OP)
With the change to symbol based hole notes does anyone know if the note "Thru To Bore" is still the accepted way to describe the depth of a hole that intersects another hole but does not go all the way thru?

RE: Thru To Bore Note

That is still an accepted use of the terminology. I would check the ASME web site for further info.
Regards,
Namdac

RE: Thru To Bore Note

I would call out a depth. It would reduce errors of a machinist drilling through.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

I think calling out a depth would be more confusing to the Machinist.  They may think you did not intend to go into the hole and made an error.  How do you measure that anyway?  My experience is that any of the following are clear to a Machinist.  Thru to Bore, Thru to Cross-Hole, Thru One Wall just a few examples I've seen used.  For further clarity you may want to put the note in spanish as well...just kiddin'

RE: Thru To Bore Note

(OP)
Does ASME have anything to say about this? I am in the process of convincing my company to purchase a copy of the y14 series but I haven't been able to get my hands on a copy yet.

RE: Thru To Bore Note

If you say 'Thru To Bore' you are assuming that the 'bored' hole is in the part before the hole being defined as 'Thru'. What if the machinist puts in the 'Thru' hole first and the 'Bore' hole second?

The hole to a depth will work no matter how the machinist makes the part.

A drawing is to be a standalone document without sopecifying manufacturing processes.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
Sr IS Technologist
L-3 Communications

RE: Thru To Bore Note

How can you apply any tolerances to the depth of such a hole?  How can it be inspected to determine if it is WITHIN TOLERANCE?  Do you make the depth a reference dimension so that tolerances would not apply?  What then if the hole is not thru to bore, or kisses the other side of the bore?  It would still be to the drawing, since there would be no depth tolerance involved.  Do you make an exception to the standards for this type of dimension?  I realize that I'm getting a little anal about this, but it is one of those gray areas that doesn't have to be.
Machinists have to be able to do simple math.  It should be no problem to determine the hole length based on the bore locating dimensions.  A simple work around that I have used is to call out "THRU TO BORE" and include a reference depth.

RE: Thru To Bore Note

The hole can be a max dim or a loose tol. Inspection can measure that. To have the hole say "Thru to bore", the bore has a tol and it is more difficult for the machinist to know exactly where the bore is. Drilling a hole can be measured and drilled at the same setup regardless where the bore is. It is up to the drafter, designer or engineer to figure out how depp to make the hole and have the proper callout on the dwg.
We don't know the details of the design. The hole could have ref dim's or have a tight tol, I don't know.
aardvarkdw, can you show us a pic of the detail?

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

(OP)
A reference depth dimension sounds like a good way of doing this. That way the overall goal is clear but you are not telling the machinist how to do his job. If ASME doesn't address this, why? This seems to me to be something that engineers deal with every day.

RE: Thru To Bore Note

At one time it was not proper to specify the process to achieve the required geometry of the part.  Therefore, if you would indicate the diameter and the required depth in a clear manner that would eliminate part of the "Bore" problem, no?

RE: Thru To Bore Note

Thanks for the pic.
Sorry to be picky. But ...
Since you show hidden lines for the internal geometry, there isn't a need to say "thru to bore". It is also possible to just say "2X ... thru".
The same for the .620 dia hole. I would call out "thru".
For aligned section, no need to have "section A-A", only section line. I would also call out FCF's and tol for dim's or a in a note.
This is not telling the machinist how to do his job, just good drafting practice.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

My argument about tolerancing and inspection still stands.
(getting on soapbox)
You could call out the hole as .50 deep +/-.25 and it would still be uninspectable.  You can't inspect something that isn't there, and the bottom of that hole would not exist.  It would be impossible to confirm that the hole depth fell between .25 and .75.  It may be drilled .23 deep, be fully functional, yet be uninspectable, negating ANY inspection or definition value of that tolerance callout.  If the dimension has no value to the part definition, it has no place being called out as a hard dimension.  As the designer, you don't care WHAT the depth is, as long as it is thru to bore.  Isn't that what a drawing is supposed to do- define the part, not the way to make it?
(Getting off soapbox)
There are exceptions to this, as most things.  A deeper, smaller hole intersecting with another hole of similar size would need to be tightly controlled.  But that does not involve a bore, and is another situation all together.

RE: Thru To Bore Note

(OP)
I realized after I poted the pic that that wasn't a good example. Imagine the holes don't come out the other side...

RE: Thru To Bore Note

I was busy writing my previous post, and then got to read what has been posted since.  Chris is right that the hole is SHOWN as being thru to bore, and therefore should not require a depth callout.  For that matter, technically it could be called out 2X thru entire part, if the alignment of the smaller holes is of importance.

RE: Thru To Bore Note

Ah, behind again.  Please ignore the last part of my previous post;)

RE: Thru To Bore Note

Normally what I would do in this case is, "2X THRU ONE WALL". I have never had any question with this When I have called out "... THRU TO BORE", sometimes I get "Which bore?".

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

I don't like "thru to bore", and prefer using "thru wall".  To me, "to bore" is too open to interpretation:  is a hole with just the point of the drill penetrating "to the bore" acceptable?

In ANSI nomenclature, a hole that is "thru" must pass completely through the part, having a cylindrical form of the noted diameter (plus or minus tolerances).  Thus, "thru wall" indicates that a hole of the noted diameter must pass completely thru the "wall" indicated (it should be obvious from the print which wall is intended, or else you'd better redraw the view to make it obvious).

That said, I think in 99.9% of all machine shops, either callout will be understood and correctly interpreted.  In the remaining 0.1% of shops, this callout will be the least of your worries.

RE: Thru To Bore Note

(OP)
Sorry again for the bad examples. Neither of these are my drawings they are drawings made by our engineers who are still drawing to Y14.5-1982 and I got tasked to go through them and clean them up.
http://i2.tinypic.com/11bjl0z.jpg

RE: Thru To Bore Note

Using THRU TO BORE, you could not get just the drill point breaking thru, it is the full diameter which would have to be thru to bore.
I've had managers not allow "THRU ONE WALL" (but they weren't exactly experienced in part detailing to begin with).  I have used that method often.
That is a good point about the shops knowing what is required, and if not, that would indeed be the least of your worries about any parts that they are making.

RE: Thru To Bore Note

Also, your dwg shows the holes going a depth in hidden lines. It is confusing since you indicate thru to bore. There could be a question from the machinist. I prefer THRU ONE WALL.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

aardvarkdw,

I just did look and your drawing and was wondering what and how you are tolerancing the patterns.

RE: Thru To Bore Note

A designer I knew would call out the depth to the centerline of the intersected hole. I don't know if that was his standard or a company standard, but it sounds workable and doesn't depend on which hole is put in first. We had inspectors that would pick with nits, but it never came up as an issue.

RE: Thru To Bore Note

I think it would be a lot of work for the machinist to drill to the centerline of the intersecting hole. Seems like personal preference for your designer.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-05)

RE: Thru To Bore Note

I tried opening the link to the drawing but had trouble.

I agree that giving a depth as anything other than reference makes no sense as you can't inspect it. A ref dimension to the centre of the hole you're going to might be a good idea tho'.

I was always taught that hidden detail is non preffered and sections are better but I know in some situations hidden are still useful.

Still in any situation where defining the hole using standard methods/callouts is awkward I tend to put a section.

Would wording like 'Thru to ØX.XX hole' be a way of clarifying it? Especially if accompanied by a section and reference dimension.

RE: Thru To Bore Note

Quote:

Would wording like 'Thru to ØX.XX hole' be a way of clarifying it?
That would be clearer, but now you have another problem. If the large bore ever changes size you have to remember to change all the dimensions that have that diameter referenced in them.

RE: Thru To Bore Note

The question of how to call out the depth is answered indirectly in ASME Y14.5M-1994;
"Section 1.8.9 Round Holes: ... Where it is not clear that a hole goes through, the abbreviation THRU follows a dimension."  In other words, where the geometry is clear, further detailing is not required.  In this case, the section clearly shows a tapped hole from the outside wall to the inside bore, so specifying the pre-drill and tap size is all that's required.  Machinists should know how to read an engineering print, so they would see the intersection, note the position and size of the cross-bore and do the math to ensure that the holes fully intersect.  Adding notes such as "Thru to Bore", "To Bore", "One Side Only" are redundant at best if the drawing shows the geometry correctly in section or in phantom lines, and may confuse inexperienced machinists at worst.

The only inspection to be done on the depth of a hole thru to the bore is visually verifying that it completely intercepts the cross-bore and does not enter the opposite face of the bore.  It wouldn't be an issue in this sample because there is another bore on the other side.  

SoapBox time: I would be concerned saying that this drawing somehow conforms to Y14.5M-1982.  There are no datums, no positional tolerances, no general size tolerances to cover the non-toleranced dimensions...  Without a positional tolerance on the tapped hole, the feature could be significantly out of position which would theoretically allow the tapped hole to nick the tangent of the cross bore and exit the other side of the outside diameter.  Sounds "impossible", but "legally" that part would pass inspection.
Stating that a drawing conforms to Y14.5M (any edition) sets a legal precedence that can bite you if the engineering isn't correct.  End SoapBox.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development

RE: Thru To Bore Note

(OP)
Jim,
 The drawing orignialy had a general tolerence block and such but it was removed along with notes and title block at the request of my company prior to posting. It was simply an illustration (albeit a bad one) of a note in context that I had a concern about.

 That being said, I agree with you. If the hole is shown in section a note specifying depth would be redundant, but in cases where a clear section veiw is not an option the reference depth dimention that was mentioned earlier would be the best option.

RE: Thru To Bore Note

Tks Aardvarkdw.  I was a little concerned there.

Jim

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development

RE: Thru To Bore Note

MechNorth,
I agree with your post with the exception of "specifying the pre-drill and tap size is all that's required".  The only tapped hole information required is the actual thread designation and depth of thread (as req'd), except for special situations such as where the pilot depth is critical.  The drawing should not tell the fabricator to tap, or what size pilot drill to use, as these are per existing specifications and would be redundant on the drawing.  Every machinist should have access to the Machineries Handbook.

RE: Thru To Bore Note

Fair enough, ewh.  I don't have ANSI Y14.6 or Y14.6aM (the standard for specifying and dimensioning screw threads) onhand.  I've usually used the tap call-out and depth (as needed) as directed by company stadards.  Specialty taps like SpiraLok typically need a pilot drill called out or the taps may be easily broken (from experience).

tks
Jim

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development

RE: Thru To Bore Note

You're right that this rule is not set in stone, as there are situations where more detail is involved.  As a general rule though, the machinist should know how to proceed.  It is just a pet peeve of mine, as I always seem to be bleeding on drawings because of it (and other similar mistakes).  I've had one designer brag that he had never taken a drafting course in his life.  He was a good designer, but often said "that's the way we did it at (insert any previous employer)" when it came to drafting.

RE: Thru To Bore Note

Finally got the drawing to open and you’re right that with the cross section you don’t really need the ‘thru to bore’ or variation there on, the cross section is my preferred way of doing it from my knowledge of the standards.

I'm with ewh on only calling out the thread, not how to create it/tap drill size but have also been guilty of giving more details on 'specials'.

One case I can think of though (which comes up quite often here in pneumatics) is where the thread only goes down part of the length and then the ‘tap drill’ dia continues on down to intersect with another bore or something.  

We have a problem here because by default our CAD system only has the nominal and minor dia data for screw threads in it.  So the tap hole ends up being the diameter of the screw thread minor diameter, not the true tap drill size.  To do it properly you end up creating 2 separate holes which then leads to other problems, but there you go.

Can I just say that after looking at various engineering news boards & talking to CAD users etc it’s refreshing to come across a group of engineers that actually know & care about standards etc.  I knew they existed but sometimes they seem few and far between.

Ken

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources