Shank Dia. to Threads Major Dia. Equation?
Shank Dia. to Threads Major Dia. Equation?
(OP)
Howdie.
I have an application I am building that builds relations for ProE for a whole range of fasteners. These relations are applied to a typical fastener part, that modify it to become a standard fastener at the required specs. I would imagine that most engineers would have little use for this application, but I am applying this application to 3D graphics where visual realism is the whole point. My problem is this; I have built tables for a full range of ANSI fasteners, but only for diecut threads, NOT rolled threads (yet). Because rolled threads for the most part have a shank diameter less than the major diameter, my question is, does anyone know where I can find a table that indicates what diameter of blank to use for a given threads major diameter? Does it depend on material used? Or is there a standard equation to relate the two diameters? Some sources say that the shank diameter is APPROX. equal to the pitch diameter, but I have photographs that clearly show this to be a GROSS approximation. I can't imagine that this whole process would be left to trial and error.
Thank you very much.
treddie
I have an application I am building that builds relations for ProE for a whole range of fasteners. These relations are applied to a typical fastener part, that modify it to become a standard fastener at the required specs. I would imagine that most engineers would have little use for this application, but I am applying this application to 3D graphics where visual realism is the whole point. My problem is this; I have built tables for a full range of ANSI fasteners, but only for diecut threads, NOT rolled threads (yet). Because rolled threads for the most part have a shank diameter less than the major diameter, my question is, does anyone know where I can find a table that indicates what diameter of blank to use for a given threads major diameter? Does it depend on material used? Or is there a standard equation to relate the two diameters? Some sources say that the shank diameter is APPROX. equal to the pitch diameter, but I have photographs that clearly show this to be a GROSS approximation. I can't imagine that this whole process would be left to trial and error.
Thank you very much.
treddie





RE: Shank Dia. to Threads Major Dia. Equation?
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Shank Dia. to Threads Major Dia. Equation?
Thank you for the response. So that's actually very simple then. I noticed on one fastener manufacturer's page that they used a shank dia. that was in very close agreement with pitch dia (only off by a tiny fraction). It was the photographs that were throwing me. But your explanation for variances makes perfect sense. And I would imagine that each manufacturer would build stock parts according to what works best for them and their manufacturing equipment, and the availability of blank stock sizes. So I am going to build the program to be flexible to accept variances since I am also using the program to reverse engineer parts for 3D viz.
Thanks for clarification.
treddie
RE: Shank Dia. to Threads Major Dia. Equation?
have you looked up the fastener specs (NAS, MS, etc) ?
RE: Shank Dia. to Threads Major Dia. Equation?
I pretty much followed ANSI and UTS specs from the Machinery's Handbook, but as you probably already know, that book only offers a partial description of the specs, and otherwise, you have to buy the specs which is a huge investment. So I spent literally days cobbling together specs off the web.
For machined threads, the problem was easy, and the application works great with ProE in building really great fasteners (I basically let the blank diameter equal the major diameter exactly). Rolled threads are the new addition to the app.
treddie
RE: Shank Dia. to Threads Major Dia. Equation?
RE: Shank Dia. to Threads Major Dia. Equation?
What amazes me is that no one in the CAD/Graphics industry has come up with any "real world" solutions to fasteners and springs. Sure, they have calculators up the yin-ying, but no automated part building capabaility.
As ubiquitous as those things are, they sure seem to be on the list of last things to accomplish. So I guess I just have to do it myself. I certainly got tired really quickly of having to reinvent the wheel everytime I needed a screw or spring.
RE: Shank Dia. to Threads Major Dia. Equation?
designers who has offended people they should've get the job of creating modells of rivets, hi-Loks, screws, P-clips, ... (really)
RE: Shank Dia. to Threads Major Dia. Equation?
Machined AND rolled.
...and that's just the screws.
RE: Shank Dia. to Threads Major Dia. Equation?
RE: Shank Dia. to Threads Major Dia. Equation?
If I am elected President, the U.S. will have only one standard...ANSI B18.6.3-1972, R1977. Why that one? Because that's the one I started with. No exceptions allowed.
RE: Shank Dia. to Threads Major Dia. Equation?
you can get most of the AN and MS specs. While most have been superceded by NASM specs, the content for the most part hasn't changed, just that AIA now controls the document.
David
RE: Shank Dia. to Threads Major Dia. Equation?
RE: Shank Dia. to Threads Major Dia. Equation?
For aircraft applications there are also specific bolts for shear loads (NAS1103 thru NAS1120, Hi-Loks, Huck bolts, etc). The shank is held to very close diametral tolerances and is usually slightly larger than the thread major diameter. They also tend to have thin heads and short, closely controlled thread lengths, since they are not intended to carry axial loads.
RE: Shank Dia. to Threads Major Dia. Equation?
Once I get the algorithm written for rolled threads, I'll be ready to populate the program with all of these spec tables. Lot's of work ahead.