need hole call out advise on pierce extrude hole in sheetmetal

[rossao1]

I am not aware of any set format for calling out a hole in sheetmetal that will fit a threadforming screw.

I want a hole the will fit an M3x.5 screw.

From what I know, .106 +/-.001 should do it. I want it to be 2 material thickness' after piercing and the material is .040" thick. My title block tolerance is +/-.005 on three place decimals. So is this good enough?

.106+/-.001
PIERCE EXTRUDE
.080 DEEP X .020 WALL MIN.

TIA for any wisdom thrown my way.

 

[drawoh]

rossao1,

You need to know what kind of threadforming screw is being used, and you need to read the manufacturer's literature. This will tell you what size hole you muyst provide, as well as specify what hardness your material can be. Your hole tolerance of ±.001" is pretty accurate.

This is not really a drafting and documentation problem. This is a fastener design and selection problem.

JHG

 

[MikeHalloran]

I think you need to dimension the depth of extrusion as a minimum, not an implied bilateral tolerance.



Mike Halloran
Pembroke Pines, FL, USA

 

[ajack1]

I think page 11 explains what you are looking for.

http://www.taptite.net/pdfs/documents/TAPTITEII-CONTI-REMINC.pdf

 

[rossao1]

THAT IS EXACTLY THE PAGE I USED! LOL. ;D

I was worried more about getting the notation right so that I would get a product that was manfacturable and checkable.

I have settled on this:
.106 +/-.001
PIERCE EXTRUDE
.08 DEEP X .020 WALL MIN.

BTW, my 2 place tolerance is +/-.010"

Thanks for the advice guys!