General Rule: Minimum Thickness for Threading

[Gcm7]

Hey, I have a sheet metal part on which I want to put a thread for a captive / non-losable bolt. The thread won't be load-bearing, but I need to know what is manufacturable. I have an M8 bolt and I want to use 2mm thick SS sheet metal. Is it doable? Is there a general rule for this when it comes to manufacturability?

 

[SwinnyGG]

Assuming you're wanting to use a standard M8 thread (1.25mm pitch), after threading and deburring you're likely to have less than one full thread remaining.

You'd be better off using a rivet-type stud, or a spot welded stud.

 

[EdStainless]

There are tap methods that don't use a drilled hole but just deform the metal making a bulge that is thicker for more threads. I believe that formdrill is one of them. This might give you enough local thickness for holding.

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P.E. Metallurgy, consulting work welcomed

 

[BrianE22]

Thrumpf also makes punching/extruding/tapping heads for increased thread engagement:

https://www.youtube.com/watch?v=9p1hDLdYuxY

 

[Hill Mary]

It is commonly known that the minimum recommended thread engagement to make a strong connection for a component with a tapped hole is approximately 1 times the nominal diameter in steel and 2 times the nominal diameter in aluminum.

https://www.mie-solutions.com/mie-trak-pro

 

[IRstuff]

One possible approach is sheet metal screw, which will deform the metal to get almost one thread's engagement

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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