Self-clinching nut types compared: eight series, one installation principle
Every series in this table becomes a permanent threaded boss the same way: a controlled hole, a parallel squeeze, and sheet metal that cold-flows into a clinch groove. What separates them is where they install — which panel material and hardness, how thin the sheet, how large the thread — and whether the installed screw is held against vibration. This table compares the eight clinch-nut series we publish individual specification pages for, using only fields that mean the same thing across the columns. Where the collected series sheets are silent — most of the installation-force row — the cell says so and asks you to confirm it at RFQ; nothing is filled in with an assumption, and no cell implies a series cannot be supplied.
Comparison table
Sheet-thickness and installation figures are quoted at each column's own collected reference thread and sheet and are marked as sampled bases — they position the series, they are not one interpolatable ladder.
| Field | S / CLS / SP | CLA | SMPS / SMPP | SH | CFE / CFEO | SL TRI-DENT | PEM RT | H / HNL |
|---|---|---|---|---|---|---|---|---|
| Locking behaviour The field that separates the eight in service: which columns hold the screw against vibration, and how. | Free-running internal 2B / 6H threads — no locking feature in the standard series | Standard clinch-nut thread behavior; a thread class is not tabulated in the collected CLA sheet Unverified — confirm at RFQ | Standard clinch-nut thread behavior — no locking feature in the thin-sheet series | Locking behaviour not stated in the collected SH sheet — confirm at RFQ Unverified — confirm at RFQ | Self-locking; locking performance equivalent to applicable NASM25027 specifications | Prevailing torque — friction essentially independent of axial load; 3-cycle locking performance | Free-running until clamp load is induced; locking reusability unaffected by on/off cycles | H: non-locking; HNL: prevailing-torque locking meeting IFI 100/107 Grade B and ANSI B18.16.1M |
| Thread range (collected) | #2-56 to 1/2-20 unified; M2 x 0.4 to M12 x 1.75 metric — the widest on the page | #2-56 to 1/4-20 unified; M2 to M6 metric | #2-56 to #6-32 unified; M2.5 to M3.5 metric — miniature only | 1/4-20 to 3/8-16 unified; M6 to M10 metric | #4-40 to 1/4-28 unified; M3 to M6 metric | #4-40 to 5/16-18 unified; M3 to M10 metric | #4-40 to 5/16-18 unified; M3 to M8 metric | 1/4-20 to 3/8-16 unified; M6 to M10 metric |
| Minimum sheet thickness (as collected) Each column quotes its own collected reference thread — the figures position the series, they are not one ladder. | Sampled: M4 code-1 shank serves 1.0 mm sheet; code-2 serves 1.4 mm (per-thread shank/hole ladders) | Sampled: #2-56 at .040 in.; #4-40 at .090 in. — a deliberately thicker ladder than the steel S table | 0.024–0.025 in. / 0.61–0.64 mm across the tabulated sizes — the thinnest on the page | Sampled: 1/4-20 code-1 at .056 in. sheet, code-2 at .090 in. | Sampled: #4-40 at .060 in.; M3 at 1.02 mm (CFEO) / 1.53 mm (CFE); M6 at 1.53 mm | Sampled: .070 in. at #4-40 (per-thread shank/hole ladders) | Sampled: .040 in. at #4-40 (per-thread shank/hole ladders) | Single-shank ladder: 1.48 mm / .058 in. shank into 1.48 mm / .058 in. minimum sheet across M6–M10 / 1/4-20–3/8-16 |
| Panel envelope (as collected) Sheet material and hardness ceilings differ per series — this is the match-the-series-to-the-sheet row. | S: steel/aluminium sheets HRB 80 / HB 150 or less; CLS: HRB 70 / HB 125 or less; SP: stainless sheets HRB 90 / HB 192 or less | Steel or aluminum sheets HRB 50 / HB 82 or less — the softest ceiling on the page (aluminum fastener material) | SMPS: steel/aluminium sheets HRB 70 / HB 125 or less; SMPP: stainless sheets HRB 90 / HB 192 or less | High-strength steel sheets up to 975 MPa tensile strength — the hardest-panel column | Sheet materials with Rockwell hardness B-70 or less | Steel or aluminum sheets HRB 80 / HB 150 or less | Steel or aluminum sheets HRB 80 / HB 150 or less | H: sheets HRB 80 / HB 150 or less; HNL: HRB 60 / HB 107 or less — the locking variant is the softer-panel constraint |
| Installation force (sampled, per each column's collected sheet) Each column quotes its own collected sheet, thread and test condition — the PEM CL performance data (batch x85) covers most series; figures are reference points at their named sheet, not one ladder. Confirm press capacity at RFQ; it is not a supply limit. | S: M4 code 1 in 5052-H34 aluminum: 11.2–13.4 kN (cold-rolled steel: 18–27 kN); SP: #4-40 in 304 stainless: 8000 lbs | #4-40 (shank code 1) in 5052-H34 aluminum: 800–1500 lbs; M3: 3.56–6.67 kN | SMPS #4-40 in cold-rolled steel: 1800 lbs; SMPP #4-40 in 0.7 mm 304 stainless (HRB 89): 4500 lbs | 5/16-18 (code 1) in .098 in. S700MC (HRC 23): 12600 lbs — the highest-pressure column; sheet is high-strength steel, not cold-rolled | #4-40 at .040 in. sheet: 1500 lbs; M3 at 1.0 mm: 6.7 kN; M6 at 1.5 mm: 15.6 kN | #4-40 (code 1): 1500–2000 lbs in 5052-H34 aluminum; 2500–3500 lbs in cold-rolled steel | #4-40 (code 1): 1500–2000 lbs in 5052-H34 aluminum; 2500–3500 lbs in cold-rolled steel | H at M10 / 3/8-16: 22 kN in 2.29 mm aluminum; 33 kN in 2.24 mm cold-rolled steel |
| Pushout & torque-out (as collected) Same per-column basis as the installation-force row — pushout / torque-out pairs at each column's own sampled thread and sheet. | S: M4 code 1 in aluminum: 470 N / 2.6 N·m; SP: #4-40 in 304 stainless: 130 lbs / 14 in.-lbs | #4-40 (code 1): 100 lbs pushout / 6 in.-lbs torque-out in 5052-H34 aluminum | SMPS #4-40: 60 lbs / 12 in.-lbs; SMPP #4-40: 75 lbs / 15 in.-lbs | 5/16-18 (code 1) in S700MC: 1050 lbs pushout / 265 in.-lbs torque-out — the strongest column | Sampled at #4-40 on steel: 135 lbs pushout, 10 in.-lbs torque-out (M6 at 1.5 mm: 1800 N / 11.3 N·m) | #4-40 (code 1): 90 lbs pushout / 10 in.-lbs torque-out in aluminum; 125 / 15 in cold-rolled steel | #4-40 (code 1): 90 lbs pushout / 10 in.-lbs torque-out in aluminum; 125 / 15 in cold-rolled steel | H at M10: 1760 N pushout / 21.5 N·m torque-out in aluminum; 2020 N / 27.1 N·m in cold-rolled steel — the collected figures now bear out the "high pushout" positioning |
| Best for | The default for steel and aluminium panels in the common size range — widest thread ladder and the whole S/CLS/SP panel split | Aluminum-nut applications — quoted with its own hole layout, not interchangeable with a steel-nut panel without re-checking every hole | Electronics enclosures and instrument panels on 0.6 mm-class sheet, where a full-size nut would overhang the hole or edge | High-strength steel sheet up to 975 MPa, where a soft nut body would make the installed thread the weakest link | Vibration-exposed screws that are serviced rarely and must not back out — locking without a separate locknut | Joints under vibration that are rarely or never fully clamped — prevailing torque holds even without clamp load | High-cycle service and automated rundown — free-running until clamp load, reusable locking unaffected by on/off cycles | Nuts tightened repeatedly in service, where the clinch must resist higher pushout and torque-out than the standard series |
- Verified
- Differs
- Unverified — confirm at RFQ
- Conditional — confirm configuration
How to choose
By the panel, before anything else
The clinch only forms if the sheet can cold-flow into the groove, so hardness is the first filter, not the thread. Ordinary steel and aluminium panels sit in the HRB-80 class that S, SL, PEM RT and H serve (CLS one band softer, HNL two); stainless-steel panels belong to SP or SMPP at HRB 90 / HB 192; high-strength steel up to 975 MPa tensile is SH territory, where a standard clinch nut would be out-rated by its own panel. The aluminum CLA column is quoted with its own geometry table — substituting it into a panel drilled for steel nuts means re-checking every hole.
By the sheet and the space around the hole
Below roughly one millimetre of sheet, the standard ladders start running out: SMPS/SMPP are the series that install into 0.61–0.64 mm stock, with the reduced outer diameter to sit in the tight hole-to-edge clearances of enclosures and instrument panels. At the other end, thread size pushes you outward — the miniature and thin-sheet series top out at #6-32 / M3.5, while SH and H/HNL start at 1/4-20 / M6. Match the column's collected thread range to your drawing before matching anything else.
By how the screw is serviced
If the screw goes in once and stays, the free-running standard series is the right answer. If it must never back out, the locking columns hold in different ways: CFE / CFEO lock the thread itself at NASM25027-equivalent performance, SL TRI-DENT applies prevailing torque regardless of clamp load, PEM RT runs free until clamp load indents and stays reusable across on/off cycles, and HNL adds locking to the high-pushout clinch — at a softer panel ceiling than H. The service frequency, not the strength figure, is what separates those four.
Frequently asked questions
How do I pick a clinch-nut series from this table?
Filter in order: panel first, then sheet thickness, then locking. The panel-envelope row decides which series can even be installed — SP or SMPP for stainless sheets, SH for high-strength steel up to 975 MPa, the HRB-80-class series for ordinary steel and aluminium. The sheet-thickness row then narrows further: SMPS/SMPP reach 0.61–0.64 mm where the standard ladder stops. Locking last: if the screw must resist vibration, move from S to CFE/CFEO, SL, PEM RT or HNL — each holds differently (self-locking, prevailing torque, free-running-until-clamp), so choose by how often the joint is serviced. Thread range is the final gate: the miniature and high-strength series cover narrow size windows.
Why do the installation-force figures sit at different threads and sheet materials?
Because each series page quotes its own collected performance table, and the manufacturer CL bulletin tests each series at its natural duty point: the SMPS/SMPP series at miniature threads, the SH series on high-strength S700MC sheet, the CLA series in aluminum, the H series at its largest sizes. That is a statement about how the evidence was collected, not about the fasteners — self-clinching nuts of every series install with a parallel squeezing press, and the bulletin's own guidance is to determine optimum installation force by test before production runs. State your sheet material, thickness and thread sizes at RFQ and the installation-force data will be confirmed for your case.
The sampled thickness and force figures sit at different threads — can I scale them?
No — read them as per-series reference points, each at its own collected thread and sheet. The SMPS/SMPP row quotes the series-wide 0.61–0.64 mm minimum; the CFE/CFEO row quotes #4-40 at .040 in. and M3/M6 at 1.02–1.53 mm; the CLA row quotes #2-56 and #4-40 from a ladder that is deliberately thicker than the steel S table. For your actual thread size and sheet, take the per-size row from the individual series page (or confirm it at RFQ where the column is marked unverified) — the table positions the series, it does not interpolate between them.
Individual series specification pages
Each series has its own page — hole and head dimensions, panel limits and RFQ guidance.
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