Greater Pull-Out Force: 10-32 or 10-24

[MDGroup]

Which Thread would provide greater resistance to pullout: 10-24 or 10-32?

10-24 would give you fewer threads that are coarser.
10-32 would give you more threads that are finer.

We are tapping into a thin sheet of stainless steel.

Thanks for the help.

 

[paddingtongreen]

How thin? A 1/16" thick plate would only catch 1 1/2 threads at 10-24 and 2 treads at 10-32. Neither will hold much force.

Timing has a lot to do with the outcome of a rain dance.

 

[CoryPad]

Are these fasteners self-drilling?

The question is moot. If you are relying on sheet metal screws in thin sheet metal to resist axial loads, you will be disappointed. A simple physical test of these components will provide the actual values and prove the point.

 

[MDGroup]

The sheet metal is only ~1/16" thick.
We are tapping out the hole firts.

2 screws are being used to attach a handle to a metal part that only weighs about 1-2 pounds.

So it works ok for the load. I was just wondering if we would get better results with the coarser or finer thread.

As paddingtongreen states, we can only get 1-1/2 to 2 threads. But do you think it would be better to have 1-1/2 coarse threads or 2 fine threads.

Thanks

 

[KENAT]

Do the calcs, they're posted on this site somewhere and have been in several threads.

Then try cross checking on one of the online calculators such as at

http://www.boltplanet.com

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[Compositepro]

10-24 will hold better.

 

[Tmoose]

A properly tapped hole includes a chamfer, so the working thread length is probably even less than 1/16". Depending on what the "handle" and "part" are used for, and how often they are used, there may be some issues that are not revealed at assembly, or even during funtional tests, but will be the topic of serious conversations next year

I'd test several samples through a lifetime of cycles at the anticipated working load, twice the working load, then using the part to manually crush one hundred pounds of ice cubes on the kitchen counter. Then I'd feel like the "expert."

 

[racookpe1978]

Odd that you want to tap the hole - For a thin steel piece - it's not really thick enough to be called a "plate" at 1/16 inch - you would actually get much more engagement area with a self-tapping (stainless steel) sheet metal screw.

No hole to drill. (Or a pre-hole the diameter of the sheet metal screw shank)
No tapping expense and time and setup.
No tapping machinery, or badly threaded holes.
No rework.
Wider threads on a sheet metal screw than on either a 10-32 or 10-24.

Alterate: Use a car body type clip with attached nut. Nutcert (I think) is a supplier. Better engagement, cheaper, faster, stronger. (Not as elegant looking.)

 

[mcgyvr]

There is a great selection of captive nuts for use with thin stainless steel sheet. We also extrude holes in thinner sheets to increase the pullout. You can easily get 2x material thickness with extruded holes.

 

[vc66]

Why not use PEM nuts?

V