Laser-Cut Parts With Tapped Holes and a Machined Feature, One Order

Why this can turn into separate orders

A self-serve sheet-cutting platform sells the laser cut as one service and each secondary operation as a menu item with its own list. SendCutSend’s published tapping table for sheet metal and plastic covers 4-40 through 1/2-20 and M2 through M10 (source 1). Its countersinking service offers two angles, 82° for imperial hardware and 90° for metric, limits depth to 60% of the material thickness, and lists seven materials, all aluminum or plastic (source 2).

A reamed dowel hole, a milled step, a flat face or a bore with a fit class is not among the operations on those two menus, so a buyer can end up ordering blanks from one source and the machined features from another, then carrying the tolerance stack between them. Here the print rules and the whole part is quoted as one job: cut, tapped, machined, finished and inspected, with one quote and one contact. The quote flags anything on the print that cannot be made or inspected as drawn. That is the difference between laser-cut parts as one order and a cart of separate services.

Tapping after laser cutting: pilot size, edge and depth

A tapped hole starts as a pilot sized for the tap, not the nominal thread. Wikipedia’s Unified Thread Standard table lists a #7 drill, 0.201 in, as the preferred tap drill for 1/4-20 and a #21 drill, 0.159 in, for 10-32 (source 3). For metric coarse threads the tap drill is the major diameter minus the pitch, so M6x1.0 takes a 5.0 mm pilot; for inch and metric alike that gives an approximate 75% thread (source 4). A laser-cut hole carries the cut-profile tolerance, and the quote states the tolerance used. Give the thread callout, not a hole diameter, and the pilot is sized for the tap.

A laser-cut hole has a heat-affected edge: metal that was not melted but had its microstructure and properties altered by the heat of cutting (source 5). That is why the thread callout on the print, not the laser-cut hole, is what the quote follows. Depth is bounded by thickness: a 1/4-20 has a 0.050 in pitch, the reciprocal of its 20 threads per inch (source 3), so 0.060 in sheet holds barely more than one thread. Where the sheet is too thin to hold enough threads, a self-clinching nut is the usual alternative, and PennEngineering’s FAQ gives the minimum sheet for its self-clinching fasteners (source 11). Hardware insertion covers that route and tapped and countersunk holes covers the thread callouts as a service.

Countersinks, counterbores and the machined features

A countersink is called out by the fastener it seats and its angle. Countersunk-head screws that follow the Unified Thread Standard very often have an 82° angle, and screws that follow the ISO standard a 90° angle (source 6), so the print should say which. Write the screw size, the angle and either the top diameter or the depth; a counterbore gets its diameter and depth for the head it clears. On a laser-cut blank these are machined features, measured against their own callout, not the general profile tolerance. A countersink in stainless, a material outside the menu above, is a normal build-to-print callout here.

The same goes for anything the laser cannot hold. A reamed dowel hole is dimensioned with its fit class or its own diameter tolerance, because a reamer enlarges an existing hole by a small amount with a high degree of accuracy (source 7); a milled pocket or step gets a depth with a tolerance; a locating edge the print calls out at ±0.002 in gets that number on the edge and a datum to measure from. ASME Y14.5 is the standard for how datums and tolerances are stated on a drawing (source 8). Position, perpendicularity and runout callouts are quoted from the print. The laser profile keeps the general tolerance in the title block, and the quote states the tolerance used, as covered on laser-cut tolerances; the machined callouts sit on top of it. Secondary machining covers the machined half as a service. That is how a milled part is drawn; the blank just comes from a laser. A bracket with a dowel-located mounting face is the common case, see custom machined brackets.

Order of operations, and why the finish comes last

Cut first, machine second, finish third; hardware goes in before or after the finish as the print says. A finish changes a dimension or fills a thread. Anodizing grows each surface by half the oxide thickness, and a small threaded hole may then need chasing with a tap; a common print note is that dimensions apply after all surface finishes (source 9). Powder that reaches a thread builds up on it, so threaded holes are plugged or masked before coating (source 10). Say on the print whether a thread stays bare, is masked or is chased after the finish. A finish called out on the print is quoted with the part; the finish hub explains how finishes are called out.

Inserted hardware needs the same thought. For plated panels, PennEngineering’s FAQ advises plating the panel and then installing the plated fasteners, or installing unplated fasteners in an unplated sheet and plating everything together, and says stripping and re-plating after plated fasteners are installed can damage the fastener (source 11). Hardware is supplied and installed to the print, so the print names the nut or standoff by part number and says whether it goes in before or after the finish. Where a catalog nut does not fit, a turned custom fastener in stainless, brass or steel is quoted on the same order.

What to send and how the part is inspected

Send the profile as a DXF or STEP and the callouts as a PDF: thread size and depth (or "thru"), countersink angle and fastener, dowel hole fit class or tolerance, the ±0.002 in edge with its datum, the finish and any masked threads. Name the material and thickness on the print. Any file type is accepted through the quote form, and a fully dimensioned PDF with those callouts is the clearest way to get a quote; a start from a sketch, a new sample part or photos gets a quoted CAD line. What file to send for laser cutting walks through it. Choosing between a laser blank with machined features and a fully milled part is covered in laser vs waterjet vs CNC.

Every part is inspected against your print before it ships, feature by feature: each tapped hole, reamed hole, pocket and held edge against its own callout, and the profile against the tolerance on the quote. The thread and plug gauges a buyer uses for their own checks are the subject of custom gauges, and a checking fixture for a repeat part can be quoted alongside. A single piece and a production run get the same check, with lead time quoted per job and rush available.

Sources

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

1. SendCutSend, “Tapping Service”, published service terms: sendcutsend.com/services/tapping/ (thread size range for sheet metal and plastic).

2. SendCutSend, “Countersinking”, published service terms: sendcutsend.com/services/countersinking/ (82° and 90° angles, depth limit as a share of thickness, seven materials).

3. Wikipedia, “Unified Thread Standard”: en.wikipedia.org (preferred tap drill sizes for 1/4-20 and 10-32; threads per inch is the reciprocal of pitch).

4. Wikipedia, “Tap and die”: en.wikipedia.org (tap drill equals major diameter minus pitch for metric, minus 1/N for inch, each an approximate 75% thread).

5. Wikipedia, “Heat-affected zone”: en.wikipedia.org (base material not melted but with its microstructure and properties altered by welding or heat-intensive cutting).

6. Wikipedia, “Countersink”: en.wikipedia.org (82° very often on Unified Thread Standard screws, 90° on ISO screws).

7. Wikipedia, “Reamer”: en.wikipedia.org (precision reamers enlarge an existing hole by a small amount with a high degree of accuracy).

8. ASME, “Y14.5 - Dimensioning and Tolerancing”, 2018, reaffirmed 2024: asme.org (symbols, rules and datum references for stating and reading tolerances on drawings; the standard itself is not reproduced here).

9. Wikipedia, “Anodizing”: en.wikipedia.org (oxide grows in and out equally, so each surface grows by half the oxide thickness; threaded holes may need chasing; “dimensions apply after all surface finishes”).

10. Nick Liberto, “Eliminating Powder Buildup on Threaded Holes”, Products Finishing, January 2002: pfonline.com/articles/eliminating-powder-buildup-on-threaded-holes (powder buildup on the threads of plugged holes; plugs, tape and hard masks).

11. PennEngineering, “FAQ”, PEM: pemnet.com/resources/faq/ (general minimum sheet for self-clinching fasteners; plate the panel and then install plated fasteners; stripping and re-plating after installation can damage the fastener).