Self clinching nut hole size?

Dimensions for a 10-32 nut:

OD of flat surface = .345
OD of teeth = .269
ID of teeth = .250
Length of teeth = .057



This book is saying I should use a .250 diameter hole. Not sure because my nut in the picture is not exactly in
dimension to their charts. And .250 seems a little small. Anybody do this often and just knows a simple way to find the size?

https://www.pemnet.com/fastening_products/pdf/Handbook.pdf

.250/.253 is correct for a 10-32 PEM nut.

Yes, +.003 is the over-size in the book.

The length of teeth is .057. The metal sheet is .043 thick. So I was going to cut the length of the teeth by .057 - .043 = .014. Probably .015 would be better?

rons said:

Yes, +.003 is the over-size in the book.

The length of teeth is .057. The metal sheet is .043 thick. So I was going to cut the length of the teeth by .057 - .043 = .014. Probably .015 would be better?

Click to expand...

If you machine it down, you'll cut off the lip and it won't set. There is an undercut that the sheet material flows into and keeps the PEM from falling out of the hole. It would also change the hole size needed, since the end of the flange is a taper.

The minimum sheet thickness for that PEM is .056".

If that is a stainless steel PEM, it's a CLSS-032-2. You need a CLSS-032-1, which is for minimum sheet .040". The length of the flange is .038", which is fine for your .043" sheet.

I cut off .016 from the tooth end which did not take away any tooth length. But as you said, that was the portion that would center the nut before pressing.
What I just did was to make a two step size collar. The larger diameter sets above the hole and then there is a .248 diameter section .020 deep that sets inside
the nut hole. The collar was made from another nut. With the collar on the outside and the nut on the inside I just insert a allen screw and tighten enough to set
the nut. Then a trip to the vise to push the nut all the way in. Thanks for your input. BTW, the nuts are stainless.

rons said:

I cut off .016 from the tooth end which did not take away any tooth length. But as you said, that was the portion that would center the nut before pressing.
What I just did was to make a two step size collar. The larger diameter sets above the hole and then there is a .248 diameter section .020 deep that sets inside
the nut hole. The collar was made from another nut. With the collar on the outside and the nut on the inside I just insert a allen screw and tighten enough to set
the nut. Then a trip to the vise to push the nut all the way in. Thanks for your input. BTW, the nuts are stainless.

Click to expand...

You are a VERY useful guy, Ron.

All the extra effort you go to to avoid using anything at all as the maker ships it makes the lazy among us feel really GOOD about our sloth!

Just the other day I was mindful of you explaining how you would cut disks and TiG weld them in, bondo, sand, and paint as fillers for making unwanted knock-outs in electrical boxes as if they had never been prepped, let alone knocked-out.

At the time, I was into ignorant stock plugs, ELSE a strip of metal as simply covered the entire side and done.

Sure nuf, in fear I might have to do it your HARDER way ELSE lose my Redneck license, I chickened out.

Ordered several new NEMA boxes with the "NK" SKU suffix. Plain boxes, No Knockouts whatsover arrived as ordered.

Seems I'd rather use a hole saw once than TiG weld and bondo many times. Let alone re-invent a PEM fastener.

Lazy, Iyam.

Keep up the good work!

I'd offer to buy yah a beer, but I'm afraid Kalifornikyah might jail yer creative ass when you went to catalytic crack or polymerize it into something less boring!