M4-3 Self Clinching Nut Stainless (qty x10)

Blue Alpine part F00118-00 is an M4-3 self clinching nut in stainless steel, ten to a pack at $2.50. It carries the same M4 thread as our M4-2, on a longer shank intended for thicker sheet.

Reading the code on an M4-3 self clinching nut

Split it at the dash. “M4” is the thread, 4 mm across the crests with a 0.7 mm coarse pitch, so a standard M4 screw runs straight in. “3” is the shank code. On this kind of hardware the shank code tells you how long the shank is, and that sets the thinnest sheet the nut will clinch into properly.

With the common numbering, codes go up as shanks get longer. A -3 therefore wants a heavier panel than a -2 with the same thread. Next to the M4-2 clinch nut the difference is easy to miss in a photo, so it’s an easy one to order wrong.

Measure the sheet before you order a self clinching nut

Use calipers on bare metal, close to the hole. Paint or powder coat adds thickness the clinch can’t use, so measure at a cut edge or a scraped spot. Check two or three places. Sheet near a bend isn’t always as uniform as you’d think.

Then compare your number with the minimum sheet thickness the maker lists for the M4-3. If the panel is thinner, a -3 is the wrong part however close it looks. Skip gauge numbers for this. The same gauge means a different thickness in steel than in aluminum, so work in millimeters or inches. The sheet metal article on Wikipedia has the gauge tables if you’re curious.

What a mismatched shank does

Too long for the panel, and the shank end stands proud of the back face. The collar can’t move enough metal to fill the undercut, so resistance to push-out and to turning both drop. Often nobody notices until a screw goes in and the self clinching nut turns with it. Fit the code that was there originally and you avoid the whole problem.

Setting up the press

A self clinching nut needs a squeeze, not a strike. You want two flat, hard faces on either side of the job, parallel to each other, brought together by a press. A bench arbor press is the usual tool. A hammer and punch won’t give an even push, and a bench vise can close slightly out of square, which tips the nut over as it goes in.

• Hole: punched or drilled to the diameter in the maker’s spec for this part number. A clean, round hole clinches better than a ragged one.
• Sheet: flat around the hole and outside the minimum edge distance.
• Position: shank in the hole and the nut square to the sheet before any force goes on.
• Stop point: shoulder down flat on the panel. Pressing harder after that only bends the sheet.

Checking a self clinching nut after pressing

Look at it edge-on first. No gap under the shoulder, no tilt. Then start an M4 screw with your fingers. It should run a few turns freely; if it binds straight away, the thread may have been squeezed out of round. Last, snug the screw and watch the nut. Any rotation at all means the clinch hasn’t taken.

Questions we get about the M4-3

Is a self clinching nut the same as a PEM nut?

In everyday use, yes. PEM is PennEngineering’s brand, and the name gets used for the whole category. Wikipedia lists the type under swage nut.

Can I reuse one I pressed out?

Treat it as scrap. Pressing it out rips the knurl and undercut free of the metal they locked into, and the hole can come out a little larger.

Which screw goes with an M4 self clinching nut?

Any standard M4 coarse-thread screw, at whatever length the old one was. The M4 screws we carry are listed in fasteners and tools. Still not sure about the code? Include the part number from your manual in a message through our contact page, or call +1 (443) 514-5708.