VF44 through VF210 frame mapping, A/F/P/BU flange option decoder, the VF-vs-W hybrid distinction, Italian f.s. service factor conversion and Korean replacement equivalents.
Bonfiglioli’s VF series is the most cross-referenced Italian worm gear reducer family in Asian industrial maintenance — installations span packaging, conveyor, mixing and food/beverage process equipment imported from European OEMs over the past three decades. The VF designation covers single-stage worm gear reducer units in eleven standard frame sizes from VF44 (smallest) through VF250 (largest), with several flange option suffixes that change the mounting interface. Sister W series adds a helical pre-stage for higher ratios — superficially similar but architecturally distinct. The article below decodes the VF frame ladder, the A/F/P/BU flange option suffixes, the Italian f.s. service factor convention that diverges from German DIN, and the Korean equivalents that close the supply gap.
Among major European worm gear reducer brands, Bonfiglioli VF is generally considered the most forgiving cross-reference target for two reasons. First, Bonfiglioli has historically published full dimensional drawings as standard catalogue documentation — meaning Korean manufacturers can match mounting interfaces precisely without reverse engineering. Second, the VF range uses metric (ISO) bolt patterns throughout, with no JIS or NEMA variants to complicate the substitution.
The result is that Italian VF cross-reference typically delivers a true drop-in replacement worm gear reducer experience — the Korean equivalent ships, bolts in, and runs at matched performance without machining or adapter plates. Verification still matters (the six-step compatibility check below remains essential), but the failure rate on VF substitutions is meaningfully lower than on JIS or legacy UK-origin gearbox families.
Bonfiglioli’s VF numbering reflects centre distance in millimetres between worm and wheel axes — same convention as Fenner FU and most European brands. The eleven standard frames map onto Korean equivalents in a tight one-to-one correspondence at most sizes.
VF44
VF49
VF63
VF72
VF85
VF110
VF130
VF150
VF185
VF210/250
A complete Bonfiglioli VF code includes a flange option suffix that changes the mounting interface. Reading these suffixes correctly is essential — a Korean cross-reference specified for the wrong flange variant will not bolt in. The four common suffixes:
A
Foot mount with hollow output shaft
Most common configuration. Worm gear reducer bolts to base via foot pattern; output is a hollow shaft sleeve fitting over driven equipment.
Cross-ref: Korean WPDS hollow-bore variant
F
Output flange mount
Worm gear reducer attaches to driven equipment via output flange (no foot). Common for direct-drive applications where the gearbox cantilevers from the machine.
Cross-ref: Korean WPWO output flange variant
P
Pendulum / shaft-mounted
Worm gear reducer hangs on the driven shaft, anchored only by a torque arm. No mounting feet or rigid flange. Common on conveyor head pulley drives.
Cross-ref: Korean WPDS + torque arm bracket
BU
Universal mount (multiple options)
Convertible mounting — foot, flange, and shaft-mount possibilities pre-engineered into the housing. Versatile but usually higher unit cost.
Cross-ref: Specify target mount, then standard equivalent
A common confusion across Bonfiglioli installations is the difference between VF (single-stage worm) and W (helical-bevel-worm hybrid). The two share Bonfiglioli aesthetics and broad frame envelopes, but their architectures and ratio capabilities differ substantially. Specifying the wrong replacement worm gear reducer architecture is the most expensive cross-reference mistake in the VF lineup.
BONFIGLIOLI
VF Series
Architecture: Single-stage worm and bronze wheel only.
Ratios: i = 7 through i = 100.
Efficiency: 70-85% at full load.
Self-locking: Yes at i ≥ 30.
BONFIGLIOLI
W Series
Architecture: Helical pre-stage feeds worm wheel — two reductions in series.
Ratios: i = 30 through i = 800.
Efficiency: 80-92% at full load.
Self-locking: Limited (helical reverses).
For broader two-stage wormwielreductor architecture context, the helical-worm hybrid section in our companion cross-reference guide explains the staged-reduction tradeoff in depth.
Bonfiglioli catalogues use the Italian f.s. (fattore di sicurezza) convention which differs subtly from German DIN and Korean SF practice. f.s. is published as a multiplier ranging 0.6 to 2.5; values below 1.0 indicate the worm gear reducer is rated above duty (under-loaded), values above 1.0 indicate the duty exceeds catalogue baseline (oversized requirement).
The conversion to Korean SF practice is straightforward but must be applied: Korean SF = Italian f.s. × 1.0 (same scale, same meaning). The naming difference is purely linguistic. However, when comparing nameplates across European brands, a Bonfiglioli f.s. of 1.4 is equivalent to a German DIN SF of 1.4, equivalent to a Korean SF of 1.4 — but if the original Bonfiglioli was specified at f.s. 1.4 for shock duty, the replacement worm gear reducer must carry SF ≥ 1.4 for the same application.
Even on the most forgiving European worm gear reducer family, six checks confirm that the Korean cross-reference will install without rework. The list applies to standard VF foot-mount (suffix A); flange-mount (F) and pendulum (P) variants add separate flange-specific checks.
01Frame number match — VF49 → NMRV 050, VF63 → NMRV 063, etc. Verify against the ladder above.
02Flange suffix match — A, F, P or BU on the original determines the Korean variant family.
03Trailing ratio digits — VF63/30 means i=30. Capture the number after the slash before quoting.
04Output shaft details — solid (Ø + key) or hollow (bore Ø + keyway). Hollow bore variants must match within ±0.05 mm.
05Motor flange variant — Bonfiglioli typically IEC; verify motor frame size on actual installation.
06f.s. service factor — read original f.s. value, specify Korean SF ≥ that value for the worm gear reducer replacement.
▰ MISTAKE 01
Treating VF and W as interchangeable
VF (single-stage) and W (two-stage helical-worm) share aesthetics but not architecture. A VF replacement on a W application loses ratio range — and a W replacement on a VF application loses self-locking.
▰ MISTAKE 02
Skipping the flange suffix
Specifying “VF63” without the A / F / P / BU suffix lets either side guess the mount — a 50/50 chance of mismatch on the resulting Korean variant.
▰ MISTAKE 03
Misreading the f.s. value
An original f.s. of 1.6 is not the same as 0.6. The leading “1” in 1.6 is meaningful — it indicates the duty exceeds catalogue baseline by 60%.
▰ MISTAKE 04
Ignoring shaft hand convention
Bonfiglioli specifies left-hand and right-hand worm versions for some VF frames. Korean replacement worm gear reducer must match the original hand or rotation reverses.
▰ MISTAKE 05
Forgetting OEM lubricant grade
Bonfiglioli factory-fills with synthetic for some frames, mineral for others. Verify the original lubricant family before specifying the Korean replacement fill.
Q: How accurate are Korean equivalents on Bonfiglioli VF dimensions?
A: For VF44 through VF150 frame sizes, Korean NMRV and WPA worm gear reducer equivalents match the published Bonfiglioli dimensional drawings to within ±0.5 mm on critical mounting interfaces (foot bolt centres, output shaft height, motor flange diameter). VF185 and VF210 sizes occasionally diverge 1-2 mm on shaft height; verify against drawings before committing. The two largest frames (VF250 and above) typically require dimensional confirmation since fewer Korean factories stock matched bodies.
Q: My nameplate shows “VF/W” — is that a single unit or a hybrid?
A: “VF/W” or “W with VF output” indicates a Bonfiglioli combined unit — typically a W-series helical-worm followed by a VF single-stage worm gear reducer for very high reductions. These are specialty configurations rather than catalogue standard. Korean cross-reference for “VF/W” combinations requires custom engineering quote since the Korean equivalent is usually two separate units coupled, not a single integrated housing.
Q: What is the typical capital saving on Korean cross-references vs Bonfiglioli OEM?
A: For VF44 through VF150 frames the typical worm gear reducer capital reduction is 35-55% vs Bonfiglioli channel pricing in Asia. Smaller frames (VF44, VF49) show the largest percentage savings since Korean manufacturers compete heavily in that volume range. Heavy-frame units (VF185+) narrow to 25-40% savings as fewer Korean factories produce equivalent body sizes. Lead time savings 1-3 weeks shorter than European OEM channel for stocked Korean equivalents.
Q: Can a Korean WPDS replace a Bonfiglioli VF when output is hollow bore?
A: Yes — WPDS hollow-bore variants are designed specifically for this VF-A cross-reference scenario. Bore diameter, keyway, and locking ring positions match Bonfiglioli VF-A standards on frames VF49 through VF150. For larger frames, verify the bore tolerance class — Bonfiglioli typically specifies H8, Korean WPDS production typically meets H8 but request the specific tolerance grade for your application before ordering.
Q: Do Korean cross-references match Bonfiglioli’s noise level rating?
A: Bonfiglioli VF noise levels typically run 60-72 dB(A) at 1 m for frames VF49-VF110 at rated input speed. Korean WPA and NMRV worm gear reducer equivalents typically run 62-74 dB(A) — within 2 dB(A) of the Italian original, well below human discrimination threshold. For acoustically sensitive applications (food packaging halls, medical environments), specify the lower-noise variants explicitly when requesting the cross-reference quote.
Q: How quickly can I get a Bonfiglioli cross-reference quote?
A: For standard VF44 through VF150 frames in standard A/F flange variants, our engineering team typically returns a verified Korean worm gear reducer cross-reference quote with dimensional drawing within 24 hours. For non-standard configurations (P pendulum mount, VF/W combinations, custom output shaft), allow 2-3 business days. Stocked Korean worm gear reducer bodies ship in 1-2 weeks; non-stocked variants in 3-4 weeks.
Send us the complete VF code (including flange suffix and ratio), photos of the existing unit, application context, and motor specifications. Our Korean engineering team returns a dimensional drawing and TCO comparison within 24 hours.
Redacteur: Cxm
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