# Orbital Finishing Sander Hewn Tool Library · https://hewn.build/tools/orbital-finishing-sander Corrected: An independent reviewer read this entry and found corrections. They have been applied to the text, and the reviewer re-checked the correction that mattered most for safety and found it done; the others have not been re-checked yet. The list at the end is the record of what changed. Cite as: "Orbital Finishing Sander." Hewn Tool Library, hewn.build/tools/orbital-finishing-sander. Reviewed 2026-07-27. --- ## identity **one-line:** A powered sander that mounts a **rectangular** abrasive pad on an **eccentric (off-centre) bearing so the pad ORBITS** in a small circle — but, unlike a common random-orbit design, the pad is **RESTRAINED from free rotation** (for example by elastomeric mounts), so under pure orbital translation **every point on the pad traces substantially the same small circle** [H5]. The path is therefore more regular and repeating than a random-orbit pad's, which can leave a regular scratch pattern; either type can still leave visible scratches or swirls. Gear-driven eccentric (forced-rotation) sanders, where the platen is deliberately turned by an eccentric gear pair, are a **separate related variant** with a different path and are not covered by the statement above [H5; A6]. **name:** Usually **orbital sander**, **finishing sander**, or **sheet sander**; in its dominant one-hand form the **palm sander** or **quarter-sheet sander** ("sheet sander" or "quarter-sheet finishing sander" is the clearest name for the constrained rectangular electric tool); **"jitterbug"** is a trade nickname, mainly pneumatic and autobody, that overlaps with these names but is not a precise mechanism specification (Harbor Freight, Sioux, Taylor Pneumatic, EMAX and National Detroit sell tools so named [H4; M10]; current products vary in pad size, attachment, orbit, vacuum provision and even orbit terminology, and Chicago Pneumatic markets a rectangular "jitterbug" using "random orbital" wording, per the reviewer `[manual, relayed]`). The nickname's *origin* is undocumented, plausibly the autobody trade c.1940s; flagged. Match a "jitterbug" only after checking the exact model's action, pad size, abrasive attachment, air demand, orbit and extraction type. Sized by the fraction of a standard sandpaper sheet its pad takes: **quarter-sheet** (the palm form), **third-sheet**, and **half-sheet** (the larger two-hand form) [H8; A1]. **NAMING TRAP:** consumers and retailers routinely say "orbital sander" when they mean the **[[Random-Orbital Sander]]** — the two are different tools (a random-orbit pad makes the path less repetitive, though neither is guaranteed swirl-free), and the slippage is itself a documented buying mistake (beginner-trap, below) [A1; M9]. **family / category:** Abrading tools — a member of the **COATED-grit POWERED TIP** the [[File]] founded, sitting between the [[Disc Sander]] (its rotary co-parent of the random-orbital) and the [[Random-Orbital Sander]] (a related tool compared against it throughout). Like every powered-tip member it abrades by **coated grit** (a plain sandpaper sheet, or a hook-and-loop disc on some models), so it sits on the same family boundary the Run-155 tree refresh flagged OPEN — *toothed steel* vs *abrasion by any fixed grains.* Within the tip's REMOVE / TRUE / FINISH division (Run 158), it is a **FINISHER** — specifically the constrained-orbit form, whose path is more regular than a random-orbit pad's. --- ## ✦ how NOT to use it — the heaviest section *This is a related tool to the random-orbital, and its misuse layer is read against it. Where the random-orbital's defect was "press too hard and it reverts to a disc sander," a constrained orbit tends to leave a more regular pattern, which can be harder to hide and show worse under finish; either type can leave swirls. In HSE's category figures it is the lower-vibration tool, and generally less efficient at stock removal than a random-orbit or belt sander, but it is not hazard-free: it carries a finish-dust fire hazard, abrasive-contact and electrical hazards, and chronic dust and vibration exposure. — Haft, reading the sources; revised in the fix pass.* **NOT-FOR** - **Stock removal / flattening / dimensioning** — it is generally less efficient than a random-orbital or belt sander at the same grit, though cut rate still depends on grit, pressure, tool and material (the DWE6411 manual says it can remove material rapidly, especially with coarse paper, and advises checking the work often, per the reviewer `[manual, relayed]`); it is a poor choice for correcting a cupped panel, a glue-up ridge, or mill marks. "They don't remove a lot of material" — finishing prep only. Use a [[Belt Sander]], hand plane, or drum/thickness sander first [A1; A7]. - **Truing or fitting to a line** — no registered table or fence; it follows the surface, it cannot true an end square (that's the [[Disc Sander]]) [A1]. - **Drywall and any application the exact manual prohibits** — see *the human side*; check the exact manual. - **Inside (concave) curves and acute internal corners** — the flat rectangular pad can't conform to a hollow; an acute internal corner is the *detail/delta* sander's job (mechanism-reasoned) [H7]. **DANGEROUS (injures the user)** *Rebuilt in the fix pass; the original called the hazard "the chronic pair" and omitted the fire warning.* - **★ FIRE: finish dust can self-ignite.** The DeWalt DWE6411 manual, read directly on 2026-10-16, says: "Empty dust bag frequently, especially when sanding resin coated surfaces such as polyurethane, varnish, shellac, etc." and "The accumulation of fine sanding dust particles may self ignite and cause fire." It instructs: "Dispose of coated dust particles according to the finish manufacturer's guidelines" and "Remove coated dust particles from the premises daily." [H9]. The review adds that the manual directs disposal in a tightly closed metal can `[manual, relayed]`. Extraction moves potentially self-heating finish dust into a concentrated bag or collector, which is why the between-coats use this entry recommends carries this warning. Controls: **the exact sander manual and the finish manufacturer's SDS and instructions govern collection and disposal;** empty the bag frequently; contain coated dust in noncombustible, tightly closed containers where specified; remove it from the work area and the premises; keep it away from ignition sources. OSHA's woodworking guidance likewise treats fine sander dust as a fire and explosion hazard (source capture, housekeeping, ignition control, never blowing accumulated dust down with compressed air) [H10]. This is separate from, and more specific than, the general statement that airborne wood dust is combustible. - **Acute hazards.** Contact with the moving abrasive can abrade or lacerate (OSHA, per the reviewer `[manual, relayed]`). Secure the work, keep hands clear of the pad, and inspect often. Watch for hidden wiring behind the surface, cord entanglement, loose clothing, damaged paper, electrical exposure, and an unsuitable dust-collection setup. The sander can remove material rapidly with coarse paper (see *not-for*). - **Painted and coated surfaces.** Identify old paint and other hazardous coatings before sanding. The DWE6411 manual states: "Sanding of lead based paint is NOT RECOMMENDED due to the difficulty of controlling the contaminated dust." [H9]; the reviewer notes it also provides additional isolation and cleanup precautions `[manual, relayed]`. Treated lumber, silica-bearing material, metal, filler and finish chemistry call for their own assessment. - **Vibration — Hand-Arm Vibration Syndrome (HAVS).** HSE's category ranges are risk-assessment data, not a rating for every sander: **orbital sanders 4–12 m/s2 with a recommended initial value of 9 m/s2; random-orbital sanders 6–14 m/s2, initial 12 m/s2** (read directly 2026-10-16) [M1]. These are broad ranges for tool categories; tool power, balance, pad, abrasive, maintenance, process and grip are uncontrolled, so **this entry draws no causal conclusion** about why one category differs from the other. **For work covered by the UK Control of Vibration at Work Regulations 2005, the EAV is 2.5 m/s2 A(8) and the ELV is 5 m/s2 A(8); other jurisdictions may regulate differently, and a user should apply the workplace rules that apply to them and the exact tool's representative vibration data** (the US sets no numerical HAV limit). Initial estimate only: at 9 m/s2 the EAV is reached in roughly 35 to 37 minutes of trigger time and the ELV in roughly 135 to 150 minutes (the reviewer's figures, `[manual, relayed]`; HSE's points table puts 9 m/s2 between 100 and 200 points per hour, against 100 points for the EAV and 400 for the ELV [M1]); about 20 minutes corresponds to the top of the orbital-sander range, near 12 m/s2. The original entry's "roughly 20 minutes" at 9 m/s2 was an arithmetic error and is withdrawn. HSE's method adds points across **all** vibrating tools used in a day (cumulative trigger time) and requires representative vibration data; keep EAV and ELV distinct. HAVS is **incurable**; the British Woodworking Federation names sanders among its causes [M5]. - **Dust — carcinogenic and combustible.** Wood dust is an **IARC Group 1 carcinogen** (causally linked to nasal/sinus adenocarcinoma, strongest for hardwoods) [M2]; OSHA and NTP recognise it as carcinogenic, with an OSHA PEL of 15 mg/m3 total and 5 mg/m3 respirable and a **NIOSH REL of 1 mg/m3** (occupational values, not a substitute for identifying lead paint, treated lumber, silica-bearing material, metal, filler or finish chemistry) [M3; M4]. Sanding is among the higher-exposure operations, but exposure limits require representative measurement, so this entry does not state that every dry use exceeds a limit. **Point-of-source extraction reduces exposure but does not eliminate it:** match the extractor and filter to the material, maintain the system, use the paper-hole pattern correctly, wear respiratory protection suited to the material, and assess residual exposure. - **Not a purely "chronic" tool.** The enclosed oscillating pad has no exposed spinning disc, so the [[Disc Sander]]'s up-side-hurl and the [[Angle Grinder]]'s burst are not this tool's typical danger, but the acute hazards above still apply (mechanism-reasoned comparative — flagged) [M1; M2]. **DAMAGING (ruins the work)** - **The repeating swirl / cross-grain "pigtail" — a characteristic failure of the constrained orbit.** A constrained orbital pad produces a more regular path; a random-orbit pad makes the path less repetitive. Either can leave visible scratches or swirls: debris, abrasive condition, pressure, speed, stroke overlap and finish inspection matter for both, and Bosch's random-orbit manual explicitly warns that operating technique can cause swirl marks (per the reviewer, `[manual, relayed]`). A regular pattern can catch light at consistent angles and show under stain or clear. A trade voice puts it bluntly: "sheet sanders leave swirl marks — that is what they do and how they work"; technique (fine grit, with the grain, light pressure) matters most [M7; A1; M6]. - **Dwelling in one spot** — moving too slowly concentrates the cut and digs a shallow hollow [M6; M8]. - **Skipping grits** — its scratches are coarser than a random-orbital's at the same grit, so a 120→220 jump leaves a 120 scratch the 220 never reaches; it appears at finish. "Never skip three grits" [M7]. - **Dull / loaded paper** — worn grit burnishes instead of cutting and drags debris into the grain (mechanism-reasoned; standard abrasive science) [M8]. - **Tilting the pad / rounding edges** — lifting one edge concentrates the cut and rounds a crisp arris or burns through veneer [M6]. **BEGINNER-TRAP (looks fine until it isn't)** - **The swirl you can't see until the stain goes on.** A pigtail-marked surface looks uniform on raw wood under shop light; the marks only appear when stain/finish floods them — by which point the part is coated or assembled. "You may not see these swirls on raw wood, but a coat of stain will highlight them" [M8; M7]. The family's recurring invisible-until-finish trap, *worse* here than on the random-orbital because the pattern repeats. - **Expecting it to remove real stock efficiently.** The instinct is to reach for the palm sander to flatten a glue-up or kill mill marks; it is generally slower at that than a random-orbit or belt sander [A1]. - **Running with no dust extraction, or ignoring the dust bag.** It seems to work fine dry — but trapped grit rolls under the pad as loose abrasive (deeper scratches) *and* doses the user with a Group-1 carcinogen, both invisible in the moment [M8; M3]; and a full bag of finish dust is a fire hazard (see *dangerous*). - **Buying the wrong tool entirely.** "Orbital sander" is used colloquially for the **random-orbital**, so a beginner often buys this constrained-orbit sander expecting the less repetitive path of a random-orbit tool; the names are interchangeable in casual speech and on some store signage, the tools are not [A1; M9]. **LINEAGE-MISUSE (treating it like its descendant, sibling, or ancestor)** - **Like a [[Random-Orbital Sander]]** — a common error: expecting the result of a random-orbit pad from a constrained one. The two paths differ in regularity, but neither promises a swirl-free surface, and the sources here do not show that one was invented to cure the other's pattern. Technique and abrasive condition govern both [A1; M6; M7]. - **Like a [[Disc Sander]] / rotary or [[Belt Sander]]** — expecting aggressive removal. It generally sits at the low end of the removal spectrum, below a random-orbital at equal grit; forcing it to hog material burnishes the work and wastes the day [A1]. - **Like its own hand-block ancestor** — assuming the powered orbit is "just a faster sanding block": the block (moved by hand, with the grain) leaves no repeating machine pattern; a constrained orbit can. The machine bought speed at the cost of a pattern the hand never made [A1]. --- ## correct use (brief — the workbench holds the deep operation) The orbital finishing sander's genuine strengths are **fine finishing, between-coats prep, and corner/edge work**; it is generally less efficient for stock removal than a random-orbit or belt sander, though cut rate still depends on grit, pressure, tool and material: - **Final finish-sanding and between-coat scuffing** (typ. 150 → 180 → 220, and 220–320 between finish coats) before stain, paint, or clear [A1; A7; M6]. Between-coats sanding is conditional on the coating manufacturer's recoat instructions, cure state, abrasive grade, a lead/chemical assessment of any old coating, and safe disposal of the dust (see *dangerous*). - **Sanding flush into 90° corners and tight to face frames / raised edges / baseboards** — work a round pad may not reach (the square pad's corner advantage, model-specific in detail) [A1; A7]. - **Light smoothing** of already-flat, already-dimensioned surfaces — it generally removes *less* than a random-orbital at equal grit, which suits finishing and limits everything else [A1]. Technique that keeps the finish clean: **sand WITH the grain** (especially at coarser grits — a fixed-orbital's scratches are visible cross-grain) [M6; A1]; **don't skip grits** (its scratches are coarser than a random-orbital's at the same grit, so jumping 120→220 leaves a scratch the 220 can't reach — it surfaces under stain) [M7]; **light pressure, let the tool's weight work** (pressure locks the orbit and digs/burnishes) [M6]; **keep it moving** (dwelling digs a hollow) [M6; M8]; **start the pad flat on the work, lift while running, then power off** (prevents touchdown gouge) [M6]; and **use point-of-source dust extraction suited to the material** (it reduces exposure but does not eliminate it; trapped grit can also scratch the finish) [M8; M3], and empty the bag as the finish-dust warning requires. --- ## matching **does:** finish-sands flat surfaces with a rectangular pad; scuff-sands between finish coats; preps surfaces for paint/stain/clear; knocks down raised grain and dust nibs; **sands flush into 90° internal corners and tight against edges, face frames, and baseboards** (its irreplaceable operation — the round random-orbital can't); light final smoothing of already-flat stock. Generally removes less material than a random-orbital at equal grit; cut rate still depends on grit, pressure, tool and material. **suits:** the FINISHING stage of woodworking/cabinetry/furniture/trim (corners and edges especially); between-coat prep **conditional on the coating manufacturer's recoat instructions, cure state, abrasive grade, a lead/chemical assessment, and safe disposal of the dust** ("painted/primed surfaces" is too broad without identifying the coating); painting & decorating prep; autobody hand prep in tight spots (pneumatic jitterbug, matched only after checking the exact model); the everyday DIY/hobby finish-sanding job. Materials: solid wood, veneer (carefully), filler, and coated surfaces only as above. **Not drywall: check the exact manual; some sheet sanders expressly prohibit drywall use (DeWalt DWE6411) [H9].** **match keys (fix pass):** constrained sheet/pad sander versus random-orbit or forced-rotation action; electric versus pneumatic drive; platen dimensions and the sides designed to sand flush; clamp, PSA or hook-and-loop attachment; paper size and extraction-hole pattern; approved materials and explicit prohibited applications; model vibration data and extraction compatibility; finish-dust collection and disposal instructions. **kit-fit:** lives at the *corner/edge and between-coats* end of the finishing sequence — **PAIRS WITH** the [[Random-Orbital Sander]] (ROS does the open flat field with a less repetitive path; this does the corners/edges it can't reach — complementary, not redundant) and the detail/delta sander (for acute internal corners); runs **plain 9″×11″ sheet sandpaper cut to size** (and H&L on some models). **SUBSTITUTES FOR** a hand-sanding block on flat finish work. **CANNOT replace** the [[Belt Sander]]/[[Disc Sander]] or a hand plane for stock removal/truing, nor the random-orbital for large-area swirl-free finishing. **not-for:** - stock removal, flattening, dimensioning, or truing to a line (generally less efficient than a belt/disc sander or plane) - drywall or any application the exact manual prohibits - relying on it for a swirl-free finish on stain-grade flat fields (a constrained pad leaves a more regular path; a random-orbit pad makes it less repetitive, but neither is guaranteed swirl-free) - inside concave curves / acute internal corners (flat or rectangular pad — use a contour or detail sander) - coarse cross-grain sanding on show surfaces (the repeating swirl shows badly under stain) - long uninterrupted trigger time without HAVS awareness (at HSE's initial value of 9 m/s2 the EAV is roughly 35 to 37 minutes, an initial estimate; cumulative trigger time across all tools governs) **access:** the classic **beginner's first power sander** — cheap, one-handed, and generally gentler than a random-orbit or belt sander, though it can still remove material quickly with coarse paper and damage veneer, edges and finishes. Entry: Black+Decker BDEQS300, Ryobi, Craftsman, Harbor Freight Hercules. Mid: Makita BO4556, DeWalt DWE6411K, Bosch GSS20-40, Milwaukee M18 (cordless). Pro/pneumatic (autobody/production): Sioux, Dynabrade, National Detroit jitterbug. **Consumable note:** the quarter-sheet electric form commonly accepts ordinary 9 x 11-inch sheets cut into quarters on compatible clamp models; compare actual abrasive size, attachment, hole pattern, quality and local cost against a random-orbital's discs rather than assuming a price or brand rule. **revival:** the sander a maker most likely *already owns* — so the highest-value match in the finishing category is telling them what the tool they have is genuinely *for* (corners, edges, between-coats, final prep) and the one quiet thing it can do to a stain job if misused (a regular scratch pattern, invisible until the finish floods it). Matching must also surface the exact-manual check, the drywall prohibition for some models, and the finish-dust fire warning. The cross-trade "jitterbug" name overlap is worth surfacing, with a model-specific check; the HAVS, dust and fire hazard content is strong and gives Reed real safety to surface to a beginner who'd never think a gentle palm sander carries a carcinogen and an incurable vibration injury. --- ## anatomy - **Rectangular platen / pad** — a flat, machined-aluminum-backed base (e.g., Bosch's "precision-machined aluminum sanding plate") with a foam/rubber face that holds the paper and cushions contact. Its **square corners** are the tool's one irreplaceable feature (corner/edge reach) [A1; A2]. - **Eccentric (offset) spindle + counterweight** — the motor shaft drives a spindle mounted off-centre, so motor rotation moves the pad through a small circular **orbit**; a counterweight opposes the eccentric mass to cut the vibration reaching the hand [H5; A2]. - **Rotation restraint (the defining part)** — what makes it *fixed*-orbital: the pad is held from spinning freely, for example by **elastomeric mounts**; under pure orbital translation the path is therefore regular and repeating [H5]. (A common random-orbit design instead permits free rotation about an offset bearing; a gear-driven eccentric sander deliberately turns the platen and is a separate variant [H5; A6].) - **Paper attachment — spring/lever CLAMPS** — front and rear sprung clamps grip a plain sandpaper sheet at both ends; the traditional, still-dominant design (many models *also* accept hook-and-loop or PSA paper) [A2; A3]. - **Punch plate (hole punch)** — a pinned template that punches dust-extraction holes through a plain sheet to align with the pad's holes; shipped in-box on dust-collecting models [A2]. - **Dust path** — holes in paper → holes in pad → a fabric **dust bag** or a sealed **microfilter canister** (Bosch's canister is rated to capture to ~0.5 micron); or a port for an external vacuum. A supplied dust bag is not necessarily equivalent to an extractor suitable for carcinogenic dust, and concentrated finish dust in a bag is a fire hazard (see *dangerous*). The fixed-orbital's dust-extraction lineage starts at the 1966 RTT-S [A2; H3]. - **Specs** — **OPM** typically **12,000–16,000** orbits/min (Bosch 12,000; Milwaukee 13,000; DeWalt 14,000; some 16,000); **orbit diameter ("throw")** small, commonly **~1.6 mm (1⁄16″)** on quarter-sheet models (some larger/European pads ~2.4 mm) [A2; A4; A5]. - **Drive** — corded electric (dominant; ~2.0–2.4 A), cordless (e.g., Milwaukee M18), or **pneumatic** (the jitterbug; ~90 psi) [A2; A4; A-pneu]. --- ## variations (living) - **Quarter-sheet "palm" sander ("jitterbug")** — the dominant one-hand form; pad ~4½″×5½″; the classic first sander [A1]. - **Third-sheet sander** — pad ~3⅔″×9″; more coverage per pass [A1]. - **Half-sheet sander** — pad ~4½″×11″; the larger two-hand form for big flat surfaces, less common in the consumer market [H8; A1]. - **Detail / corner / "mouse" / delta sander** — fixed-orbital on a **triangular** pad whose point reaches acute internal corners; a descendant/variant (US 5,437,571, 1992; B+D "Mouse") [H7]. - **Profile / contour sander** — interchangeable shaped pads (finger/cone/curved) for mouldings; an adjacent oscillating cousin, not a flat-pad orbital [A-contour]. - **Pneumatic orbital square sander** — the air-driven jitterbug; an overlapping name, not a mechanism guarantee: current products differ in pad dimensions, attachment, orbit size, vacuum provision and orbit terminology (Sioux and Dynabrade list dedicated rectangular pneumatic orbital tools; Chicago Pneumatic markets a rectangular "jitterbug" with "random orbital" wording, per the reviewer `[manual, relayed]`); typically ~90 psi in the sources here, but require the exact model's air demand [H4; A-pneu]. - **Geared / forced-rotation eccentric sander** — a separate related variant in which the platen is deliberately turned by an eccentric gear pair; it follows a different path and has its own matching behavior, not described by this entry's constrained-orbit definition [H5; A6]. - **Cousins, NOT this tool (named to bound it):** the **[[Random-Orbital Sander]]** (common free-spinning round pad — a less repetitive path; a related tool); the **straight-line / inline air "file"** (pure reciprocating linear stroke — autobody filler levelling); the **[[Disc Sander]] / rotary** (single-axis spin — aggressive) [A1; A-file]. --- ## trades (where it appears, with notes) **Woodworking, cabinetmaking & furniture** (final prep and between-coats, and corner/edge finishing; the cabinet shop's "around-180-grit" hand-off tool) [A1; M7]; **painting & decorating** (between-coat prep; the square pad's flush-to-corner reach) [A1]; **autobody / collision repair** (the pneumatic "jitterbug" for jambs, edges, and tight corners; filler/fibreglass/metal) [H4; M10]; **not drywall** (the DeWalt DWE6411 manual prohibits it; check the exact manual) [H9]; **general DIY / hobby** (the first power sander most households own, on cheap cut-sheet paper) [A1; M9]. Naming is trade-split, like the random-orbital's: woodworkers say "orbital / sheet / palm sander," body shops say "jitterbug" — and *both* are loosely (and wrongly) called just "orbital," colliding with the random-orbital [A1; H4]. --- ## lineage **ancestors (upstream):** - **Hand-sanding on a cork/felt block** — the un-mechanised finishing operation this tool replaced; a sheet of sandpaper held in the hand, an abrasive but never a *named tool* in the corpus (the same point the random-orbital entry made: the hand family had no finishing *machine*). The orbital finishing sander is the first powered tool to give block-sanding a motor [A1]. - The **[[Disc Sander]]** — a spinning-disc relative with rotary motion; a sibling here (this tool orbits, it does not spin a plate) [corpus: [[Disc Sander]] Run 156]. - **Coated abrasive (sheet sandpaper; the standard 9″×11″ sheet)** — the functional substrate and the tool's organizing constraint: the pad is sized to a *fraction of the standard sheet* so plain paper can be cut to fit with no waste (history, below). Like its belt/disc/ROS siblings it CROSSES the toothed-steel family boundary the Run-155/157 refreshes flagged OPEN [H8; A1]. **siblings (same powered-abrasive era, different geometry):** - The **[[Belt Sander]]** — the powered tip's REMOVER (endless linear loop) [corpus: Run 154]. - The **[[Disc Sander]]** — the powered tip's TRUER/FITTER (fixed-axis rotary plate) [corpus: Run 156]. - The **in-line / straight-line air "file" (longboard) sander** — a *reciprocating* (pure back-and-forth linear) relative used in autobody for feathering filler; same plain-sheet abrasive economy, but a fundamentally different (non-orbital) motion and scratch pattern. Named to bound this tool, not a member-claim [A-file]. **descendants (downstream):** - The **[[Random-Orbital Sander]]** — a related tool compared against this one: a common design keeps an eccentric orbit and permits free rotation of the pad about an offset bearing, making the path less repetitive (not guaranteed swirl-free). Whether it descended from this tool is not shown by the sources here [corpus: Run 158]. - The **detail / corner / "mouse" / delta sander** — the fixed-orbital mechanism on a **triangular** pad whose point reaches into acute internal corners the rectangular pad can't; a variant, commercially c.1992–94 (US 5,437,571 "Detail Sander": 1992 priority date, U.S. application filed May 10, 1994, issued August 1, 1995, per the reviewer `[manual, relayed]`; Black+Decker "Mouse" line) [H7]. - The **geared / forced-rotation finishing sander** — a separate related variant whose platen rotation is controlled by an eccentric gear pair (per the patent background, `[manual, relayed]`); it is kept out of this tool's definition [corpus: [[Geared Dual-Action Sander]] Run 160]. > **TREE NOTE.** This entry promotes the **`FIXORB`** node from a NAMED, UN-BUILT ancestor ghost (carried since the Run-157/158 refreshes) to a **BUILT member** — the COATED tip's constrained-orbit FINISHER, a related member of the finishing line (not a documented ancestor of the random-orbital). It is integrated into the [[_Abrading Family — Lineage Tree]] this run with a **light inline touch** (node promoted, one node-table row, the two existing `==` parent links re-pointed from the descendant onto a built node), NOT a refresh. --- ## history & origin **The honest headline: this tool inherits the random-orbital's contested "first," one generation up, and its own dated record is THINNER than its descendant's.** There is no single arbitrated origin. What is on record: - **Festo (later Festool, Germany)** claims the **first orbital sander, the RTE "Rutscher," 1951** — an eccentric-orbit flat-pad tool that replaced the hand-sanding block for painters, joiners and auto-body painters; "Rutscher" became a Festool-protected name, and the company cites 250,000 units sold by the early 1960s as the scale proof [H1]. - **Rupes (Italy)** claims the **first portable electric sander, the Model 123 "Stork," 1951** — the *same year* [H2]. The two claims are coincident, not litigated; each is a corporate self-attestation. **Critically, the** Stork's *motion type is unconfirmed* — Rupes' own timeline does not state whether the 1951 Stork was fixed-orbital, straight-line, or rotary, so it cannot be cleanly equated to Festo's orbital claim. (Rupes' *later* dated milestones are internally consistent and bear on the descendant: the **BR 8, 1968**, "first electric random orbital sander," and the **LE 7, 1974**, "first electric orbital *palm* sander" [H2].) - **The pneumatic "jitterbug" is older than both electric claims.** National Detroit Inc. (Rockford, IL) self-dates its air-sander line to **1939**, and its Model 400 "Jitterbug" (3⁄16″ orbit) is described as the original of the type [H4] — which, if taken at face value, would place a *pneumatic* orbital sander in the autobody trade a decade-plus before the 1951 *electric* claims. This is an attributed manufacturer/retailer claim, not independently established (the reviewer). (Source is maker/retail — MED — but it mirrors the random-orbital entry's identical finding that the pneumatic DA, also National Detroit, 1939, predated the electric ROS.) **One possible reading of the conflict (labelled interpretation, not a verdict):** the *orbital principle* may have appeared first in the **air-powered automotive** world (the pneumatic jitterbug, late 1930s/1940s, if the dealer date is right), and the **portable electric** finishing sander arrived in Europe around 1951 (Festo's *Rutscher*, with Rupes claiming a portable-electric first the same year by a possibly-different mechanism). I do not crown one, and I do not assert the *Stork* was fixed-orbital. **The dust-extraction landmark (firmer).** Festo's **RTT-S, 1966**, is credited as "the world's first orbital sander that not just caught dust, but actively extracted it" — the development a named engineer (Karl Attinger) drove after a high-dust two-part putty, by punching holes in the paper and adding a hose; Festool dates its whole no-handheld-machine-without-extraction policy to it [H1; H3]. Point-of-source extraction reduces dust exposure but does not eliminate it (see *dangerous*). **The patents — an honestly THIN spine (the entry's main weakness).** Where the random-orbital had a firm primary patent spine (the named "Random orbital sander," the pad brake, the dual-action latch), this tool's foundational patent could **not** be verified: - **The defining MECHANISM is primary-sourced:** US **2003/0032381 A1**, "Orbital Sander," states the constraint in its own words — the platen "is constrained so that it can orbit, but cannot freely rotate relative to the housing," and in one embodiment "orbits at high speed about the motor axis while being slowly rotated by an eccentric gear pair" [H5]. This is the cleanest available statement of *the* fact that distinguishes the fixed-orbital from the random-orbital. - **The quarter-pad FORM is primary-sourced:** US **6,190,245**, "Quarter Pad Sander," a Dynabrade pneumatic quarter-pad patent, filed August 21, 1998 and issued February 20, 2001 (per the reviewer, `[manual, relayed]`); it is not the origin of the quarter-sheet electric form [H6]. - **The detail/delta VARIANT is dated:** US **5,437,571**, "Detail Sander": 1992 priority date, U.S. application filed May 10, 1994, issued August 1, 1995 (per the reviewer, `[manual, relayed]`) (+ US 5,533,926 on the triangular pad/support) [H7]. - **NOT verified — named as gaps, not used:** a frequently-repeated secondary claim of a *Millers Falls / Fred Williams Moore 1951* eccentric-orbit patent could not be confirmed at source; the *David R. Wickes 1955* dual-mode patent the random-orbital entry already dropped is again **dropped**; a *Traut ~1948* hand-sander patent (US 2455626, surfaced only in later patents' prior-art) is **not** asserted. The foundational pre-1951 flat-pad electric orbital patent remains **unlocated.** **Into the modern shop.** Festo spun its power-tool arm off as Festool in **2000** [H1]. The tool is widely available from multiple manufacturers as of the original review date (current-product status changes; official product pages should be checked) — for example Bosch (GSS-series), DeWalt (DWE6411K), Makita (BO4556), Milwaukee (M18 cordless 2649-20), Black+Decker (BDEQS300, the archetypal cheap entry sander), Ryobi, Ridgid, Porter-Cable, Craftsman — alongside the pneumatic jitterbug for production/autobody (Sioux, Dynabrade, National Detroit) [A2; A4; A5; M10; M11]. --- ## ✦ proof of existence - **Primary patents (Google Patents, verified):** US **2003/0032381 A1**, "Orbital Sander" — the defining *constrained-rotation* mechanism in its own words [H5]; US **6,190,245**, "Quarter Pad Sander" (Dynabrade, pneumatic; filed 1998-08-21, issued 2001-02-20, per the reviewer) [H6]; US **5,437,571**, "Detail Sander" (1992 priority; U.S. application filed 1994-05-10, issued 1995-08-01, per the reviewer) (+ US 5,533,926, triangular pad/support) — the delta-sander variant [H7]. (A 1951 sander patent, US 2,627,705 "Sander Head," is *verified* but is a rotary drum head, not a flat-pad orbital — cited only as evidence of concurrent 1951 sander patent activity, not as this tool's origin.) - **Manufacturer-primary maker histories & dated tools:** Festo/Festool company history (*Rutscher* 1951; **RTT-S dust extraction 1966**, with named engineer Karl Attinger; Festool independent 2000) [H1; H3]; Rupes timeline (*Stork* 1951; BR 8 1968; LE 7 palm sander 1974) [H2]; National Detroit air-sanders self-dated **1939** (the "Jitterbug" Model 400) [H4]. - **Consumable-economy record:** the 9″×11″ standard sheet and its 1/4-/1/3-/1/2 fractions, with the Porter-Cable 330 (quarter) and 505 (half) as the canonical examples [H8]. - **Present availability:** widely available from multiple manufacturers as of the original review date, for example Festool, Rupes, Bosch, DeWalt, Makita, Milwaukee, Black+Decker, Ryobi, Ridgid, Sioux and Dynabrade; this does not show an exhaustive or stable market [A2; A4; A5; M10; M11]. **Proof gaps (honest):** **The origin "first" is contested and unresolved** — Festo *Rutscher* 1951 vs Rupes *Stork* 1951 (the *Stork's motion type unconfirmed*) vs the pneumatic jitterbug 1939, all corporate/retail self-attestations, none arbitrated; presented as a conflict, not a date. **The foundational pre-1951 flat-pad electric orbital patent could not be located/verified** (the *Millers Falls/Moore 1951*, *Wickes 1955*, and *Traut ~1948* claims are all unverified and NOT asserted) — this is the entry's main weakness and the reason it grades below its descendant. **No museum accession located** (the Smithsonian NMAH route is unconfirmed for an orbital sander — the same gap the disc and random-orbital entries flagged). The **"jitterbug" nickname origin** is undocumented. The per-brand orbit-throw figures beyond the 1.6 mm consumer standard, and the half-sheet OPM/throw specs, are partial. The three structural readings are **labelled interpretation**; the "freed bearing" idea is an analogy only. --- ## references - **H1** Festool / Festo company history (Fezer & Stoll 1925; RTE *Rutscher* 1951 "first orbital sander," 250,000 sold by early 1960s; RTT-S 1966; Festool independent 2000) — https://www.festool.com/company/company-history — manufacturer (self-attestation) — MED (HIGH for own claims) - **H2** Rupes timeline / history (Model 123 *Stork* 1951 "first portable electric sander" — motion type unstated; BR 8 random-orbital 1968; LE 7 orbital palm sander 1974) — https://www.rupes.com/timeline-history/ — manufacturer (self-attestation) — MED - **H3** Festool "Pioneers in dust extraction" (RTT-S 1966, first orbital sander with active dust extraction; Karl Attinger) — https://www.festool.com/blog/inside/automotive — manufacturer blog (named source) — MED-HIGH - **H4** National Detroit Inc. (Rockford IL; "air sanders since 1939"; Model 400 "Jitterbug," 3⁄16″ orbit, "the original Jitterbug sander") — http://ndsander.com/400-series/ — manufacturer / retail — MED - **H5** US Patent App. US 2003/0032381 A1 — "Orbital Sander" (platen "constrained so that it can orbit, but cannot freely rotate relative to the housing"; "slowly rotated by an eccentric gear pair") — https://patents.google.com/patent/US20030032381A1/en — patent (primary) — HIGH - **H6** US Patent 6,190,245 — "Quarter Pad Sander" (Dynabrade pneumatic; filed 1998-08-21, issued 2001-02-20 per the reviewer; the quarter-pad form) — https://patents.google.com/patent/US6190245 — patent (primary) — HIGH - **H7** US Patent 5,437,571 — "Detail Sander" (1992 priority; U.S. application filed 1994-05-10, issued 1995-08-01 per the reviewer; the triangular/delta variant) + US 5,533,926 (sandpaper pad/support for a detail sander) — https://patents.google.com/patent/US5437571 — patent (primary, secondary citation for filing date) — MED - **H8** 2Sand, "Why That Size? (9×11 sandpaper)" (the standard sheet and its 1/4/1/3/1/2 fractions; Porter-Cable 330 quarter / 505 half as canonical) — https://2sand.com/blog/why-that-size/ — trade — MED - **H9** DeWalt DWE6411 instruction manual — https://assets.dewalt.com/GLOBALBOM/QU/DWE6411/1/Instruction_Manual/EN/N457047_DWE6411.pdf — read directly 2026-10-16 (fix pass): drywall prohibition, resin-coated dust self-ignition and disposal, lead-paint warning — manufacturer (primary) — HIGH - **H10** OSHA, "Woodworking: Fire and Explosion" — https://www.osha.gov/etools/woodworking/safety-hazards/fire-explosion — read directly 2026-10-16 (fix pass): fine sander dust fire hazard, source capture, housekeeping, ignition control — federal (primary) — HIGH - **H11** Bosch GET65-5/GET75-6 random-orbit sander manual; Chicago Pneumatic CP7266CVE; Sioux finishing-tools catalogue; Dynabrade Dynabug II — URLs as listed in the review; **relayed from the reviewer, not read in this pass** (`[manual, relayed]`): swirl marks possible with a random-orbit sander; mixed "random orbital" terminology on rectangular pneumatic products — manufacturer — MED - **A1** Fine Homebuilding, "What's the Difference: Fine-Finish Sanders — Orbital vs. Random-Orbit" (the square-corner advantage; removes less than ROS; uses regular sandpaper cut to fit; grain-direction sensitivity; "handy for places where a random-orbit won't fit") — https://www.finehomebuilding.com/2016/01/06/whats-the-difference-fine-finish-sanders-orbital-vs-random-orbit — trade magazine — HIGH - **A2** Bosch GSS20-40 product page (precision-machined aluminum plate; traditional spring-clamp design, also accepts stick-on paper; microfilter canister to ~0.5 micron; in-box punch plate; 12,000 OPM) — https://www.boschtools.com/us/en/products/gss20-40-06012A2110 — manufacturer (primary) — HIGH - **A3** Engineer Fix, "What Is an Orbital Sander / Sheet Sander and How Does It Work?" (eccentric drive; clamp attachment; mechanism) — https://engineerfix.com/what-is-an-orbital-sander-and-how-does-it-work/ — trade explainer — MED - **A4** Milwaukee M18 1/4-Sheet Orbital Sander 2649-20 (13,000 OPM; 1.6 mm orbit) — https://www.milwaukeetool.com/products/details/m18-orbital-1-4-sheet-sander/2649-20 — manufacturer (primary) — HIGH - **A5** DeWalt DWE6411K 1/4-Sheet Palm Sander (14,000 OPM) — https://www.amazon.com/DEWALT-DWE6411K-Sheet-Palm-Sander/dp/B00ZWJDN5S — manufacturer/retail — HIGH - **A6** Crazy4Tools / Triton geared eccentric orbital sander ("fixed orbit mode" — a gear mechanism locks the pad from free-spinning, vs a free-spin mode) — https://www.crazy4tools.com/geared-eccentric-orbital-sander.html — retail/trade — MED - **A7** Kreg Tool, "Orbital Sander vs. Sheet Sander" (corner/edge access; slow material removal; finishing role) — https://learn.kregtool.com/learn/orbital-sander-vs-sheet-sander/ — manufacturer/trade — MED-HIGH - **A-file** Hutchins Mfg, straight-line / longboard air sanders (the reciprocating autobody relative — distinct motion, same sheet abrasive) — https://hutchinsmfg.com/straight-line-sanders/ — manufacturer — MED - **A-pneu** WoodArtSupply / generic air square-orbital finishing sander (the pneumatic jitterbug variant; ~90 psi) — https://woodartsupply.com/products/air-orbital-sander-air-square-orbit-finishing-sander — retail — MED - **A-contour** Homebase, "Guide to the different types of sanders" (the contour/profile sander as an adjacent oscillating category) — https://www.homebase.co.uk/en-uk/ideas-and-advice/our-guide-to-the-different-types-of-sanders — retail/trade — MED - **M1** HSE (UK), "Hand-arm vibration — assess the risks," Table 1 (orbital sander 4–12, initial 9 m/s²; random-orbital 6–14, initial 12 m/s²; points table, EAV 100 points, ELV 400 points per day) + Control of Vibration at Work Regs 2005 (EAV 2.5, ELV 5.0 m/s² A(8)) — read directly 2026-10-16; HSE calculator guide (hse.gov.uk/vibration/hav/calculator-guide.htm) says time to EAV and ELV comes from its spreadsheet and gives no 9 or 12 m/s² times — https://www.hse.gov.uk/vibration/hav/assessrisks.htm — government (primary) — HIGH - **M2** IARC / WHO, *Wood Dust and Formaldehyde* (Group 1 carcinogen; nasal/sinus adenocarcinoma; strongest for hardwoods) — https://publications.iarc.who.int/80 — IARC (primary) — HIGH - **M3** OSHA, "Wood Dust — Hazards" (human carcinogen; combustible-dust hazard) — https://www.osha.gov/wood-dust/hazards — federal (primary) — HIGH - **M4** CDC/NIOSH, Wood Dust (NIOSH REL 1 mg/m³; OSHA PEL 15 total / 5 respirable) — https://www.cdc.gov/niosh/pel88/wooddust.html — federal (primary) — HIGH - **M5** British Woodworking Federation, "Hand-Arm Vibration Syndrome (HAVS)" (names sanders; HAVS incurable) — https://www.bwf.org.uk/bwf-blog/hand-arm-vibration-syndrome-havs/ — trade body — MED-HIGH - **M6** Uneeda / sandpaper.com, "How to avoid and fix swirls from your 3×4 orbital sander" (the single-trajectory repeating pattern; with-grain, cross-hatch, light pressure, start-on/stop-off) — https://www.sandpaper.com/articles/how-to-avoid-and-fix-swirls-from-your-3x4-orbital-sander/ — trade abrasives — MED - **M7** Woodweb, "Avoiding Swirl Marks in Finish Sanding" (pro consensus: "sheet sanders leave swirl marks — that's what they do"; never skip grits; swirl shows at stain) — https://woodweb.com/knowledge_base/Avoiding_Swirl_Marks_in_Finish_Sanding.html — trade forum (corroborated) — MED-HIGH - **M8** Red Label Abrasives, "How to eliminate swirl marks from orbital sanding" (swirls invisible on raw wood until stain; trapped dust as loose abrasive; dwelling) — https://www.redlabelabrasives.com/blogs/news/how-to-eliminate-swirl-marks-from-orbital-sanding/ — trade — MED - **M9** LumberJocks, "1/4 sheet palm sander vs random orbit sander" (cheap to run on standard sheet sandpaper; ROS gives the better finish — the naming/buying confusion) — https://www.lumberjocks.com/threads/1-4-sheet-palm-sander-vs-random-orbit-sander.16686/ — forum — LOW-MED - **M10** Harbor Freight / Taylor Pneumatic / Sioux "jitterbug" air sanders (the live trade nickname on current product) — https://www.harborfreight.com/jitterbug-orbital-air-sander-90115.html ; https://taylorpneumatic.com/products/t-8865-jitterbug-sander-3-3-4-x-4-1-4 — retail — MED - **M11** Makita BO4556 (the recommended mid-range quarter-sheet) + Black+Decker BDEQS300 (the archetypal cheap palm sander) — https://makitatools.com/products/details/BO4556 ; https://www.amazon.com/BLACK-DECKER-BDEQS300-Orbital-Actuati/dp/B00OJWLVM6 — manufacturer/retail — MED ## ✦ the structural readings (held as interpretation, revised in the fix pass) Three readings, each an interpretation of sourced facts. The original run framed the first two as consequences of one evolutionary step; the review found that genealogy unsupported, so they are now presented as a mechanical comparison and an inference. **1 — A mechanical comparison, not an ancestry.** A common pad sander constrains platen rotation, so the platen follows a small orbit; a common random-orbit design permits free rotation about an offset bearing, which makes the path less repetitive [H5]. The original entry called the random-orbital "this tool with one bearing set free." That survives here **only as an explanatory analogy**: it is not documented design history, not proof that one tool descended from the other, and not a stated inventive motive. US 2003/0032381 A1 is a 2001-filed application whose preferred embodiment is itself a random-orbit palm sander; it is not an origin patent, and its background describes already-existing classes (random-orbit, constrained pad, and a less common eccentric sander whose platen rotation is controlled by an eccentric gear pair) (per the reviewer, `[manual, relayed]`). Every abrader Haft has built leaves a signature track; the useful comparison is how regular that track is, not which tool "fixed" which. > **Honesty flag.** The constrained-versus-free mechanism is sourced to the patent's background. The "one freed bearing" phrase is the original run's synthesis, kept as a marked analogy. **2 — Common free-spinning pads are round; rectangular constrained pads keep corner access.** Common free-spinning random-orbit sanders use round pads, while rectangular constrained-orbit pads can preserve edge and corner access [A1; A7]. The corner advantage is directly sourced (Fine Homebuilding states the square foot "allows it to get in corners and up against edges" [A1]; Kreg Tool concurs [A7]); it is model-specific in detail (the DeWalt DWE6411 is described as sanding flush on three sides, not every corner of every square sander, per the reviewer, `[manual, relayed]`). The engineering reason a free-spinning pad is round (a non-round pad changes radius, balance, snagging and clearance) is **an inference, not a design-source finding**; a non-round pad can in principle rotate on an open flat surface, and some manufacturers use "random orbital" for rectangular pneumatic products, so market terminology is not clean. **3 — The matching/ownership reading: a commonly owned first power sander whose paper is cheap to source.** The quarter-sheet electric form commonly **accepts ordinary 9 x 11-inch sheets cut into quarters on compatible clamp models** [H8; A1]. Random-orbit discs are specified by diameter, attachment and hole pattern; compare actual abrasive size, attachment, hole pattern, quality and local cost rather than assuming a brand rule. The pneumatic "jitterbug" (National Detroit, self-dated 1939 [H4]) is an attributed manufacturer/retailer claim; it is not proof that a pneumatic fixed-orbit branch predates the electric tool or that autobody precedes woodshop. > **Honesty flag.** The paper-size fact and first-sander status are sourced (Fine Homebuilding [A1]; trade/forum [M9]). The 1939 claim is MED, a dealer/maker date not independently established (the reviewer). --- ## ✦ the human side **The first sander most people ever own — and, like its descendant, a tool with two trades and two names.** The quarter-sheet palm sander is the default *first* power sander in North American woodworking and DIY: cheap, small, one-handed, and generally gentler on stock than a random-orbit or belt sander (though it can still remove material quickly with coarse paper). Its consumable economy is the human fact under the popularity — the quarter-sheet electric form commonly runs on **plain sheet sandpaper cut into quarters** on compatible clamp models rather than a purpose-specific disc, so a beginner is not punished for sanding a lot (a real, repeatedly-confessed reason hobbyists keep one even after buying a random-orbital) [A1; M9]. **The "jitterbug."** In the body shop the pneumatic tool is the **jitterbug** — an overlapping trade name still on current product (National Detroit Model 400; Sioux, Taylor Pneumatic, Harbor Freight, EMAX all sell "jitterbug sanders") [H4; M10]. The nickname almost certainly comes from the tool's fast, jittering oscillation, and its likeliest birth is the late-1930s/1940s autobody trade (the dance was at peak popularity exactly as National Detroit's air sanders appeared in 1939) — but no source actually documents who coined it or when; carried as undocumented folk etymology. **Trades that centre on it.** - **Woodworking & cabinetmaking** — between-coat scuff-sanding (conditional on the coating manufacturer's recoat instructions, cure state and safe disposal of the dust, see *dangerous*) and final prep before stain/paint/clear, and the corner-and-edge finishing a round random-orbital can't reach; professional cabinet shops describe a hand-off "around 180 grit," the sheet sander doing the precision corner work before finish goes on [A1; M7]. - **Painting & decorating** — between-coat prep of woodwork (identify old paint and other hazardous coatings first; see *dangerous*); the square pad's flush-to-the-corner reach is the specific advantage [A1]. - **Autobody** — the pneumatic jitterbug for hand prep on jambs, panel edges, and tight corners a 5″ round DA pad can't reach (filler, fibreglass, metal) [H4; M10]. - **Drywall — NOT a match.** The DeWalt DWE6411 manual states: "This sander is not to be used in drywall applications." (read directly 2026-10-16) [H9]. Tool-family resemblance does not override a model-specific prohibition. If a particular orbital sander is explicitly approved for drywall or joint compound, record that only at the model level with its required extraction and exposure controls. **Check the exact manual; some sheet sanders expressly prohibit drywall use.** **Named hands & makers.** **Festo → Festool** (Esslingen; Fezer & Stoll 1925; *Rutscher* 1951; RTT-S dust extraction 1966; independent as Festool 2000) [H1; H3]; **Rupes** (Milan, 1947; *Stork* 1951; the random-orbital and palm-sander milestones 1968/1974) [H2]; **National Detroit** (Rockford IL, air sanders since 1939; the "Jitterbug") [H4]; **Black+Decker** (the ubiquitous cheap palm sander, and the "Mouse" detail-sander line) [H7; M11]; **Makita** (BO4556, the repeatedly-recommended mid-range quarter-sheet) [M11]; **Sioux / Dynabrade** (the pro pneumatic jitterbugs) [M10]. --- ## Forge images this entry will need 1. **PRIORITY — "one freed bearing."** A two-panel mechanism diptych built to hang beside the [[Random-Orbital Sander]]'s "the path that never repeats" plate (HAFT image set, Run 158 #1): LEFT, this tool — the eccentric ORBIT with the pad **constrained** (a small lock/gear symbol on the bearing), the abrasive track a **repeating** closed circle; RIGHT, the random-orbital — the **same** eccentric orbit with the pad bearing **set free** (the lock removed), the track exploding into the non-repeating tangle — captioned as an explanatory analogy only ("a common random-orbit design frees the pad bearing"), not a claim of ancestry. Pair with a caption that either type can leave swirls. 2. **"Round can't, square can."** A top-down diptych of a workpiece with a 90° internal corner and a raised face-frame edge: LEFT, the **round** random-orbital pad stopped short, a crescent of un-sanded wood trapped in the corner and along the edge (red); RIGHT, the **square** orbital pad reaching flush into the corner and tight to the edge (green) — captioned "common free-spinning pads are round; rectangular constrained pads keep corner access." The visual of reading 2. 3. **"The swirl that hides until the stain."** A before/after diptych: LEFT, a raw panel sanded with the fixed-orbital, looking clean and uniform under shop light; RIGHT, the *same* panel after stain floods it, the **repeating** pigtail swirl suddenly visible across the face (and a small inset contrasting it with the random-orbital's self-erasing non-repeating path) — captioned "a fixed orbit leaves a repeating pattern; it's invisible on bare wood and obvious under finish." The visual root of the damaging/beginner-trap misuse layer. ## The reviewer's corrections (15) - `BLOCKER` — 1. — Exact claim: “Drywall — between-coat compound knock-down where corner access matters” and “drywall” in the trades list. - `BLOCKER` — 2. — Exact claim: The tool is repeatedly recommended for “between-coats,” polyurethane, varnish, shellac, paint, and clear finishing, while the safety section says only that wood dust is combustible and “Run the extraction.” - `SHOULD-FIX` — 3. — Exact claim: “At ~9 m/s² a worker can pass the action value in roughly 20 minutes and approach the limit value within ~1.5–2 hours.” - `SHOULD-FIX` — 4. — Exact claim: “The legally-enforceable UK exposure values ... the UK/EU figures are the authoritative floor.” - `SHOULD-FIX` — 5. — Exact claim: “The freed bearing that fixes the swirl also adds vibration.” - `SHOULD-FIX` — 6. — Exact claim: “The random-orbital was invented specifically to fix this tool's repeating pattern”; “this tool with one bearing set free”; “orbit-half parent”; and “ancestor.” - `SHOULD-FIX` — 7. — Exact claim: The fixed-orbital definition includes a platen “slowly turned by an eccentric gear pair,” while also saying “every point on the pad traces the same small circle at the same time.” - `SHOULD-FIX` — 8. — Exact claim: “A free-spinning pad must be round—a square pad cannot freely rotate against a flat workpiece.” - `SHOULD-FIX` — 9. — Exact claim: “The fixed-orbital is not swirl-free and cannot be made so”; the random-orbital is repeatedly called “swirl-free”; and the repeating “pigtail” is treated as exclusive to the fixed orbit. - `SHOULD-FIX` — 10. — Exact claim: “Jitterbug” is presented as a synonym for the electric quarter-sheet/palm sander and the pneumatic jitterbug is said to have the “same mechanism.” - `SHOULD-FIX` — 11. — Exact claim: “It can't easily ruin stock, only swirl a finish”; “almost no stock removal”; “it barely cuts”; and “lower projectile risk ... its hazard is the chronic pair.” - `SHOULD-FIX` — 12. — Exact claim: “a near-dustless tool”; “a bare tool run dry into open air clears [exposure limits] in a breathing zone”; and “Run the extraction.” - `SHOULD-FIX` — 13. — Exact claim: “fractions of a cent per use” for cut sheet paper and “brand- and diameter-specific discs” for random-orbit sanders. - `MINOR` — 14. — Exact claim: US 5,437,571 is described as “filed 1992,” and US 6,190,245 is described simply as a “2001” quarter-pad form. - `MINOR` — 15. — Exact claim: “current production from every major maker” followed by a list that relies partly on retailer pages.