Family parts with threads

[gumby5000]

All,

I have a longstanding question/problem regarding the creation of family parts. I am creating models of
standard fasteners in our inventory using the family part tool. All is well with this method except for
symbolic threads. There is apparently no way to add the thread callout from the thread feature into the
family part list. For example for a family of hex nuts, my family part spreadsheet might look like this:

Part_name width thickness thread
1 .438 .226 1/4-20_UNC
2 .500 .273 5/16-18_UNC
3 .562 .337 3/8-16_UNC

There's no problem with the expressions "width" and "thickness", but "thread" cannot be defined as an expression because "1/4-20_UNC" is a string and cannot be evaluated.

The only work around that I've found is to define the symbolic thread manually using extra expressions like "major_dia", "minor_dia", etc. and add them to the family table. It works, but it seems really silly to add this information in manually when it's already in the thd_english.dat file and could be just a table look-up.

Any thoughts or suggestions?

Thanks!

gumby5000

 

[vanishingpoint]

This could be done using the LOOKUP function in Excel. (Read the help section in Excel on the LOOKUP function, I would only confuse you).

Basically, you make a data file from the thd_english.dat file that you import into any part families that you might want to make. Once imported the lookup function will find the correct values for the different thread callouts.

Ken

 

[GPowers2]

I have created Part Families of Fasteners with Symbolic threads. The Part Family created was to cater for NAS1351 Socket Head Cap Screws, All sizes of thread and various length options.
The Way I captured the symbolic Thread Feature was to add a thread on the Template Part, check the exact diameter of the symbolic thread CURVES and look at Expressions to find which expression p[?] was controlling the thread curve diameter, then use this expression in the Part Family spreadsheet.
if need be do some specimen threads to determine the exact figures for other thread configuration curves. Add these to the Family spreadsheet.
I suggest you add an attribute to the Part to allow you to add the full thread specification, this will allow you to easily filter the thread specification when adding the part to a further assembly.

hope this all made sense.

Gary.
CAX Manager/Lead Designer Engineer
Moog Controls Limited