Laser-Cut Parts With PEM Nuts and Studs Installed

What self-clinching hardware does that a tapped hole cannot

A self-clinching nut is pressed into a properly sized round hole, and the squeezing force makes the sheet cold-flow into an undercut in the shank and lock the nut in place (source 3). PEM describes the result as a load-bearing thread in thin sheet (source 1). A 6-32 thread has 32 turns per inch, so 0.060 in of tapped aluminum holds under two. PEM’s FAQ gives the general minimum sheet for self-clinching hardware as 0.030 in (0.76 mm) or 0.040 in (1 mm) (source 3).

Studs and standoffs are the same idea in other shapes: a threaded shaft clinched into the sheet so a cover or board hangs on captive threads, and a standoff, which PEM describes for its MSO4 microPEM type as used "to stack or space internal components" (source 7). They come in their own PEM types, each with its own sheet hardness limit; the FHS stud, for example, is listed at HRB 70 / HB 125 or less (source 6). When the sheet is thick enough to hold its own thread and the fastener is small, a plain tapped or countersunk hole may be all the print needs.

PEM’s published limits: sheet hardness, hole size, edge distance

Self-clinching hardware only works when the fastener is harder than the sheet. PEM’s FAQ asks for a panel that is "a ductile material softer than the fastener" (source 3), and its catalog publishes a sheet hardness ceiling per nut type: S and SS at HRB 80 / HB 150 or less, CLS and CLSS at HRB 70 / HB 125 or less, and SP at HRB 90 or less (source 1). 5052-H32 is published at HB 60 and 6061-T6 at HB 93 (source 8), both under the S and CLS limits. 7075-T6 is listed at HB 150 (source 8) and at 87 HRB (source 9), at or past the type S limit, so the quote says whether the hardware suits a 7075 sheet.

Hole size is the other number that has to be right. For a 4-40 type S nut PEM lists a 0.166 in mounting hole at +0.003 in / -0.000 in and a minimum of 0.19 in from the hole centerline to the edge of the sheet (source 2); the same hole tolerance heads the column across the unified nut listing (source 1). PEM’s FAQ names "a round punched or drilled hole" (source 3). The part number, not "PEM nut", belongs on the drawing so the hole is sized for it, and for a laser-cut hole the quote states the tolerance used.

Which sheet takes which hardware

The catalog gives type S as heat-treated carbon steel, type CLS as 300 series stainless steel and type SP as age-hardened A286 stainless steel (source 1). Aluminum and steel sheet within the hardness limit take S, or CLS when a stainless nut is wanted. Stainless sheet is the exception. PEM’s installation guide says it plainly: "Don’t attempt to install a 300-series stainless steel fastener into a stainless steel sheet." (source 4).

For 304 and 316 laser-cut parts the answer is type SP, which PEM’s FAQ lists among the fasteners "designed specifically to install into stainless steel sheet" (source 3). Hardware insertion is quoted in 5052-H32 and 6061-T6 aluminum, mild steel, and 304 and 316 stainless. Name the material and thickness on the print. The 304 vs 316 page covers picking the sheet; a screw or stud that is itself a special is quoted from the print, as covered under custom fasteners.

How hardware is called out on the print

Call the hardware out on the print by part number, quantity and side of the sheet. Each hardware location needs four things: the full PEM part number (CLS-440-2 is type CLS, thread code 440, shank code 2; SP-440-1 is type SP, thread code 440, shank code 1, source 2), the quantity, the side of the sheet the head sits on, and for studs and standoffs the direction the shaft projects. A hardware table with a count per part number is the tidiest form. Note sheet thickness as a decimal (0.060 in) beside it so the shank code can be checked against the sheet.

Leave the mounting hole at PEM’s published size or note "hole per hardware", with no deburr note: PEM’s guide says "deburring will remove the metal required for clinching" (source 4). The same guide says to install into the punch side of the sheet where there is one; on a laser-cut part the print says which side the head sits on. Hardware near a bend is covered on the bent bracket page, and an enclosure blank carries its hardware the same way, at no less than the published edge distance from any cut edge. The file guide covers the rest of the drawing.

Sequence with finishing: what PEM publishes

Finish and hardware go on in an order, and the print carries it. For anodizing the guide is blunt: "Don’t install steel or stainless steel fasteners in aluminum panels before anodizing or finishing." (source 4). So on an anodized aluminum part the finish goes first and the hardware after. Where hardware goes in before powder coat, PEM lists PreTect thread masking plugs for "the paint or powder coating process", and a TP suffix on the part number orders the nut with the plug installed (source 5). For powder-coated aluminum, put the order on the print, because PEM’s rule on aluminum and the plugged-thread route pull opposite ways.

On the print, the finish spec and the hardware callout sit side by side, and the quote covers both in the order the print gives: anodize first, then hardware; or hardware, plugs, then powder coat. PEM’s guide also warns against installing on the pre-painted side of a panel (source 4). A finish called out on the print is quoted with the part. The finishing page covers how powder coat, anodize and passivation treat laser-cut parts; powder coating and anodizing go deeper.

Inspection, and what to send

The hardware is part of the print, so the check against the print includes each part number in the count the print gives and the head on the side the print shows. Pull-out and torque-out are PEM’s published figures; the quote does not state them.

Send a DXF or STEP plus a PDF print with the hardware table; the quote lists anything missing. Panels and covers for electronics enclosures and the enclosures and housings family are the common shapes, with no minimum. Upload on the quote form and a person quotes cut, hardware and finish as one order in 24-48 hours; the laser-cut parts hub lists the other second operations.

Sources

All accessed 4 October 2026. Where a figure here differs from your print, the print governs.

1. PennEngineering (PEM), “Self-Clinching Nuts - Types S, SS, CLS, CLSS, SP - Unified”, PEM catalog: catalog.pemnet.com/viewitems/nuts-types-s-ss-cls-clss-cla-sp/self-clinching-nuts-types-s-ss-cls-clss-sp-unified (nut materials, sheet hardness limits per type, mounting hole tolerance, load-bearing threads in thin sheet).

2. PennEngineering (PEM), product pages S-440-2ZI, CLS-440-2 and SP-440-1: pemnet.com/products/product-finder/s-440-2zi/, pemnet.com/products/product-finder/cls-440-2/ and pemnet.com/products/product-finder/sp-440-1/ (0.166 in hole, 0.19 in minimum hole centerline to edge, thread and shank codes).

3. PennEngineering (PEM), “FAQ”: pemnet.com/resources/faq/ (cold flow into the undercut, panel requirements, minimum sheet thickness, round punched or drilled hole, types designed for stainless sheet).

4. PennEngineering (PEM), “Self Clinching Nut Fastener Installation Do’s And Don’ts”: pemnet.com/products/engineering-guides/self-clinching-fastener-installation-dos-and-donts/ (300-series fastener in stainless sheet, anodizing, deburring, pre-painted side, punch side, install steps).

5. PennEngineering (PEM), “PEM PreTect Thread Masking Plugs”: pemnet.com/fastening-products/pretect/ (plugs for the paint or powder coating process, TP suffix).

6. PennEngineering (PEM), product page FHS-632-4, Self-Clinching Threaded Studs, Type FH/FHS/FHA: pemnet.com/products/product-finder/fhs-632-4/ (FHS sheet hardness HRB 70 / HB 125 or less).

7. PennEngineering (PEM), “Standoffs for Sheet Metal”, PEM catalog: catalog.pemnet.com/category/standoffs-for-sheet-metal (microPEM MSO4 standoffs used to stack or space internal components).

8. MakeItFrom, material property pages for 5052-H32, 6061-T6, 7075-T6 (Brinell hardness 60, 93 and 150).

9. Wikipedia, “7075 aluminium alloy”: en.wikipedia.org (Rockwell hardness 87 HRB for 7075-T6).