Formed thread

[moyesboy]

Has anyone got a model of a form tool similar to the one shown in the attached picture?
...that i can edit for my specific thread (#4 -20 tpi self tapper) - yes we are stuck with imperial self tappers here in UK.

At the moment I'm stuggling to figure out how to model the spiral tool shape for a form tool.

Perhaps someone on here has some experience with pressed threads?

This is a process where a dimpled hole is pressed into the sheet metal, but it is split and the edge of the hole formed into a spiral that matches the intended thread. Although just under one rev of thread is approximately formed, when the screw is tightened the metal is pulled in to the screw makig it stronger then you might expect.

 

[Eltron]

Check faq559-1492.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[SnowCrash]

You trying to do the form tool, right? On a plane of the punch, create a sketch that represents the quarter circle of the punch, then send it along a spiral to form a sweep. The die will be similar, except you are forming a swept cut. The helix is created from a circle sketch on the end face of the punch.
A similar technique will create the die tool and the sheet metal feature. Help will lead you through all this.
You can create the sheet metal form as a feature once it is done and not have to create it over again.
Personally, I would create a note around a hole pattern and not detail every dimple since it makes for a overly complex part file. Just call out the tool name.

--
Hardie "Crashj" Johnson
SW 2010 SP 4.0
HP Pavillion Elite HPE
W7 Pro, Nvidia Quaddro FX580

 

[moyesboy]

I figured out how to do the form tool in the end.