Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
(OP)
Question for the NX gurus/historians in the forum, what standards were used to generate the tables for the Screw Clearance Holes and Threaded Holes in NX 7.5/8.5? Working with a client that is using AMSE B1.1 (English) and AMSE B18.3 Series (Metric) for the Drill Size for Shank and Counterbore/Countersink, and some of the numbers for Close, Normal, and Loose are not matching. Could the client have had set up NX with the wrong defaults for standards?





RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
BTW, just in case you haven't actually looked for the thread and hole table files, they're located at...
...UGII\modeling_standards
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
As for where the actual numbers came from, I don't really know as I wasn't involved, at least not directly, with the project when it was being developed although I was consulted when it was originally spec'd since I was the person who collected and formatted the data files used by the legacy 'Thread' feature function (note that this feature never had any need for any sort of 'clearance hole' data so I never spent much time looking for any back when this original project was in development, which was in the late 90's).
That being said, I just dug out an old (from 1970) vendor supplied 'handbook' (this was from 'The Allen Manufacturing Company' supplier of 'Allen Head' fasteners) that I used when I first started working in engineering and I spot checked a few of the sizes included in the 'Drill Size for Shank Hole' table (Imperial sizes only) and while it only included values for 'Close' and 'Normal' clearances, most of the values I checked were consistent with what we're using in NX, to about 3 decimal places or so. I know this is not a definitive source and is certainly NOT what was used when these tables were formulated, and as someone has already noted, I'm not sure if there actually is a generally accepted 'standard'. I know the 'Machinery's Handbook' has no comprehensive set of tables, offering instead a few limited examples for some specific types of bolts or machine screws but nothing that appears to be complete, let alone definitive.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
Regards,
Tomas
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
As for a standard for Imperial size screws, I've still NOT found anything definitive. During that same search of the web, which produced a copy of the ISO standard, I found nothing equivalent to it for screws in Inch sizes. Now I have found several documents which provided virtually the same data as I already had with the vendor's 'handbook' that I mentioned in my earlier post above, also from various manufactures of fasteners. I also found references to the limited coverage in the 'Machinery's Handbook', again as I already noted above. In fact, I haven't found anything covering Imperial sizes with more than what is referred to as 'Close' and 'Free' fits. If anyone can point me to something more definitive with respect to Imperial size screws, please forward that information to me and I'll again verify if our tables match that and if not, I'm willing to open a PR requesting that the tables be updated to reflect whatever documentation is shown to be appropriate and applicable.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
When i did the quick search to find the ISO standard, i realized that one of the aspects of the clearance diameter ( Which is fully logical when i think of it...) is when achieving the tightening torque, the area under the head of the screw is important, and if this area isn't indirectly standardized, we cannot standardize a tightening torque for a specific screw diameter.
Now i don't know if the imperial screws has standardized specs like tightening torque, but the Metric screws has.
See for example :
https://www.swtc.edu/ag_power/diesel_engines/lectu...
Regards,
Tomas
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
One other note I need to past on, ASME B1.1 deals with threads (pitch, diameter, etc), but nothing for clearance holes. ASME B18.3-2003 dealt only with English/Imperial Measurements. While I have other documentation (dated back to 1987) that is referencing ASME B18.3.1M and B18.3.5M for Metric sizes, the client’s Library does not have a copy for me to review. If anyone in the forum can confirm if those two standards still exist, please let me know.
Regardless, this has been a very interesting exercise of research.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?
It will be curious to see what you dig up.
RE: Question on NX 7.5/8.5 Screw Clearance Holes - which standards were used to generate the tables?