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Technical Tapping Symbol

Technical Tapping Symbol

Technical Tapping Symbol

(OP)
Hello All,

I am relatively new to draftsmanship and am having some amount of confusion with how to specify a tapped hole.

I am currently using the solidworks hole wizard does a great job of specifying depth, csk,and radius - however it seems to make no effort to describe the tapping of the hole.

I am have done a little research and all i can asume is that there is no designated symbol for this action.

Can anyone shed any light on this?

Many Thanks

RE: Technical Tapping Symbol

I think your question belongs in the the Solidworks thread, but...

Are you using Hole Wizard to make your holes? If so, are you selecting tapped holes instead of drilled holes? If so, the callout should include the thread spec, such as "1/4-20 UNC".

Solidworks refers to a text file for the callout format for all hole wizard holes. Check Options, File Locations, Hole Callout Format File for its location. It is editable if you are truly adventurous.

RE: Technical Tapping Symbol

(OP)
Thank you Jboggs thats exactly what I wanted to hear. By looking through the calloutformat.txt file I have extracted all the tags that can be used in the hole callout text.

I havent been so adventurous as to edit it yet! but maybee soon.

Many Thanks

RE: Technical Tapping Symbol

extrudedfeature,

Actually, this is not a SolidWorks question. It is more of a forum1103: Drafting Standards, GD&T & Tolerance Analysis question.

When you call up a tapped hole, you call up the thread specification and the depth.

1/4-20UNC<depth>.50

M6X1<depth>8

You can can add the thread tolerance if you want. This makes your hole inspectable with thread gauges.

I recommend not adding the tap drill. The machinist is supposed to know this. If I have to tell someone how to tap holes, I don't want them tapping holes in my stuff.

--
JHG

RE: Technical Tapping Symbol

drawoh, That's just where I was going to send him. Exrudedfeatures, if you decide to post over in forum1103: Drafting Standards, GD&T & Tolerance Analysis, please let people here know that you have done so. You can find the thread number in the upper left hand corner, right under the title. If you run the number into the word thread (ie "thread404-") it will automatically link to your new thread so people can go there.

RE: Technical Tapping Symbol

(OP)
Thanks to you both for the directions to the correct forum. It would seem that the hole callout for metric machine screws doesnt by default contain any specification regarding thread pitch. For those who wish have this information in the hole call out for a holewizzard hole - simply add <hw-fsttyp> <hw-fstsze>. <hw-fsttyp> adds the text 'TAP DRILLS' and <hw-fstsze> adds the fastener size specified in the hole wizzard.


Appologies to the mods for the misplaced post, and thanks to those who responded.

RE: Technical Tapping Symbol

Extrudedfeature- if you don't specify pitch you should always get the standard course pitch thread. However, I never like to assume anything and always specify the pitch.

From Machinery's Handbook 27th edition:
Metric Screw Thread Designations.—Metric screw threads are identified by the letter
(M) for the thread form profile, followed by the nominal diameter size and the pitch
expressed in millimeters, separated by the sign (×) and followed by the tolerance class separated
by a dash (−) from the pitch.
The simplified international practice for designating coarse pitch M profile metric screw
threads is to leave off the pitch. Thus a M14 × 2 thread is designated just M14. However, to
prevent misunderstanding, it is mandatory to use the value for pitch in all designations.
Thread acceptability gaging system requirements of ANSI B1.3M may be added to the
thread size designation as noted in the examples (numbers in parentheses) or as specified
in pertinent documentation, such as the drawing or procurement document.
Unless otherwise specified in the designation, the screw thread is right hand.
Examples: External thread of M profile, right hand: M6 × 1 − 4g6g (22)
Internal thread of M profile, right hand: M6 × 1 − 5H6H (21)
Designation of Left Hand Thread: When a left hand thread is specified, the tolerance
class designation is followed by a dash and LH.
Example: M6 × 1 − 5H6H − LH (23)
Designation for Identical Tolerance Classes: If the two tolerance class designations for
a thread are identical, it is not necessary to repeat the symbols.
Example: M6 × 1 − 6H (21)
Designation Using All Capital Letters: When computer and teletype thread designations
use all capital letters, the external or internal thread may need further identification. Thus
the tolerance class is followed by the abbreviations EXT or INT in capital letters.
Examples: M6 × 1 − 4G6G EXT; M6 × 1 − 6H INT
Designation for Thread Fit: A fit between mating threads is indicated by the internal
thread tolerance class followed by the external thread tolerance class and separated by a
slash.
Examples: M6 × 1 − 6H/6g; M6 × 1 − 6H/4g6g

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Technical Tapping Symbol

To get around the metric pitch specification issue, we add a note to all drawings with metric threads saying something like "METRIC THREAD CALL-OUTS WITHOUT A PITCH SPECIFIED ARE COURSE PITCH".

Extrudedfeature ASME Y14.6-2001 gives info on thread call outs in US drawing system. ASME B1.1 is the actual unified thread spec.

(Thanks for the shout out Mfgenggear but I'm not sure how much help that FAQ will be for standard threads.)

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: Technical Tapping Symbol

KENAT,

I have specified metric threads by diameter only, and got fine threads. If you call up M10, some guy is going to grab the first M10 tap he sees, perhaps M10X1!

I call up pitch systematically.

--
JHG

RE: Technical Tapping Symbol

drawoh, we actually got more calls from people confused by having the pitch call out stated on the thread.

Hence having consulted the relevant thread standard we decided to add our note stating that metric threads without pitch specified were standard course pitch.

To the best of my knowledge there haven't been any problems with this.

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: Technical Tapping Symbol

Of course, I hope you spell coarse correctly on your drawings.smile

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