A right angle spiral bevel gearbox selection that appears correct on paper but misses one parameter in practice — an unstated shock load, an incorrect mounting orientation, an overlooked environmental condition — leads to premature failure, unplanned downtime, and replacement costs that dwarf the original purchase price. This guide provides a complete, systematic checklist for selecting a right angle spiral bevel gearbox that will perform correctly in service — covering every parameter from input torque through environmental sealing, in the order an experienced drive engineer would evaluate them.
The Complete Selection Checklist
Work through each section in order. Each parameter builds on the previous one — skipping sections creates gaps that cause incorrect selection.
Section 1: Drive Definition
| Parameter | What to Determine | Where to Find It |
|---|---|---|
| Input power | Motor rated power in kW | Motor nameplate |
| Input speed | Motor rated speed in rpm at full load | Motor nameplate |
| Required output speed | Speed at the driven equipment shaft in rpm | Equipment specification or calculation |
| Required ratio | Input speed / Output speed | Calculated from above |
| Required output torque (nominal) | (Input power x 9550 / Output speed) in N.m | Calculated — before service factor |
| Power flow direction | Is the pinion shaft or crown gear shaft the input? | Determines ratio direction (reduction vs increase) |
Section 2: Service Factor and Design Torque
The service factor is applied to the nominal output torque to account for load characteristics beyond steady-state rated power. The gearbox must be rated for the design torque = nominal torque x service factor — not the nominal torque alone.
| Load Type | Typical Applications | Service Factor |
|---|---|---|
| Uniform — no shock | Centrifugal fans, centrifugal pumps, light conveyors | 1.00 – 1.25 |
| Light shock | Mixers, agitators, screw conveyors (light materials) | 1.25 – 1.50 |
| Moderate shock | Belt conveyors with material loading, heavy mixers | 1.50 – 2.00 |
| Heavy shock | Mining conveyors, agricultural PTO, bucket elevators | 2.00 – 2.50 |
| Very heavy shock | Crushers, chippers, chisel applications | 2.50 – 3.50 |
The selected gearbox rated output torque must exceed the Design Torque.
Section 3: Shaft Configuration
| Configuration | Descripción | When to Specify |
|---|---|---|
| B (2-shaft) | 1 input, 1 output — standard right angle | Most applications — single driven component |
| C (3-shaft) | 1 input, 2 outputs (both sides of crown gear shaft) | Twin-shaft drives, fertilizer spreaders, stage lifts |
| D (4-shaft) | 1 input, 3 outputs | 3-point simultaneous drive — stage machinery, complex conveyors |
| Solid shaft output | Standard shaft with keyway and end face threaded hole | Coupled drive via flexible coupling |
| Hollow bore output | Bore over the driven shaft; keyway or shrink disc | Shaft-mount (torque arm) arrangement; no coupling required |
Also specify: Input shaft diameter (mm) and output shaft diameter (mm) — must match existing coupling or driven equipment bore. Specify keyway standard (DIN 6885 as default for metric; Woodruff if required). Specify shaft length if non-standard.
Section 4: Mounting Orientation
Oil fill level, vent position, and drain plug location all depend on mounting orientation. Specify the orientation as the direction of the input shaft and the direction of the output shaft:
| Orientation Description | Typical Application | Key Oil Fill Note |
|---|---|---|
| Input horizontal, output horizontal | Most common — conveyor, fan drives | Standard fill mark applies |
| Input vertical down, output horizontal | Motor above gearbox — space-saving layout | Fill level changes — must specify orientation |
| Input horizontal, output vertical up | Driving vertical shaft or screw from horizontal motor | Labyrinth seal on vertical shaft recommended |
| Input horizontal, output vertical down | Elevator drives, vertical agitators | Special oil fill required — advise at order |
| Any inverted configuration | Special installations | Must be specified at order — oil fill and vent differ significantly |
Section 5: Housing Material Selection
Select for: Service factor up to 1.75; uniform or light shock loads; indoor or protected environments. Covers: fans, pumps, light conveyors, mixers, packaging machinery, food processing.
Select for: Service factor above 2.0; heavy or very heavy shock loads; outdoor or harsh environments. Covers: mining conveyors, agricultural PTO drives, forestry, construction, crusher discharges.
Section 6: Environmental and Sealing Specification
| Environment | Specify |
|---|---|
| Standard indoor, clean | Standard NBR lip seals, standard paint (RAL 7031) |
| Dusty environment (quarry, agriculture, cement) | Labyrinth groove on shaft exits + NBR double-lip seals |
| Outdoor / rain exposure | IP65 sealing, epoxy paint with UV-stable topcoat |
| Washdown (food, pharma) | IP65 sealing, V-ring secondary seal, NSF grease/oil, SS shaft option |
| High temperature ambient (>40°C) or synthetic oil | FKM (Viton) seals — mandatory for synthetic PAO oil compatibility |
| Chemical exposure (acids, solvents) | FKM seals, 2-pack epoxy housing coat, stainless hardware |
| Offshore / marine | FKM seals, hot-dip galvanised or duplex stainless hardware, EN 10204 3.1 material certificates |
Section 7: Lubrication Specification
| Application Condition | Recommended Lubricant | Change Interval |
|---|---|---|
| Standard duty, ambient <40°C | GB L-CKC220 mineral EP gear oil (Shell Omala 220) | 2,000 hours or 1 year |
| High temperature, ambient 40–55°C | GB L-CKC460 mineral EP (Shell Omala 460) or PAO460 synthetic | 2,000 hours mineral; 4,000 hours PAO |
| Mining / extended drain synthetic | PAO ISO VG460 synthetic (FKM seals mandatory) | 4,000 hours |
| Food processing (incidental contact zone) | NSF H1 registered food-grade gear oil | Per NSF H1 oil manufacturer specification |
| Cold environment (ambient below 0°C) | PAO synthetic ISO VG220 (lower pour point) | 4,000 hours |
Section 8: Certification and Documentation Requirements
Identify required documentation before enquiring — documentation requirements affect production scheduling and cannot always be added after manufacturing has begun.
- CE Declaration — required for all machinery in the European Economic Area; Ever Power provides from our Netherlands entity as standard
- ISO 9001 Quality Certificate — included standard
- Quality Inspection Report — included standard
- EN 10204 Type 2.2 Material Certificate — available on request; specify at enquiry stage
- EN 10204 Type 3.1 Material Certificate — available on request with advance notice; required for mining, offshore, and classified pressure equipment applications
- Noise Test Record — available for stage machinery and pharmaceutical applications; specify dB limit and test condition at enquiry stage
- SGS Pre-Shipment Inspection — available on request; arrange through Ever Power or independently
Section 9: Complete Selection Summary Template
| Parameter | Your Value |
|---|---|
| Motor power (kW) | _______ |
| Input speed (rpm) | _______ |
| Required output speed (rpm) | _______ |
| Calculated ratio | _______ |
| Nominal output torque (N.m) | _______ |
| Load type / service factor | _______ |
| Design torque (N.m) = nominal x SF | _______ |
| Shaft configuration (B / C / D) | _______ |
| Input shaft diameter (mm) | _______ |
| Output shaft diameter (mm) | _______ |
| Mounting orientation | _______ |
| Housing material (cast iron / ductile iron) | _______ |
| Seal type (NBR / FKM / IP65) | _______ |
| Lubricant type and grade | _______ |
| Ambient temperature range (°C) | _______ |
| Required certifications | _______ |
| Quantity required | _______ |
Ever Power Selection Support
Ever Power is a Netherlands-registered industrial transmission company with precision manufacturing in China. Our engineering team performs the full selection calculation from your data — ratio confirmation, design torque calculation with service factor, bearing life check, thermal assessment, and documentation confirmation — and returns a matched gearbox specification with 2D CAD drawing within 48 hours of receiving your application data.
Whether you are specifying a new drive, replacing an existing unit from another brand, or designing a custom installation, we provide the technical support and documentation needed to make a correct, defensible selection — with CE certification from our Netherlands entity included as standard.
Customer Cases
Netherlands — Mixer Drive OEM, Utrecht
Submitted the full checklist to Ever Power for a 15 kW mixer drive in a chemical plant. Engineering team returned a 2:1 spiral bevel specification with service factor calculation (SF=1.5 for moderate shock) and bearing life confirmation of 28,000 hours — within 24 hours of submission. “We had the specification confirmed and the order placed before our colleagues at two other suppliers had even acknowledged our enquiry.” — Design Engineer
Australia — Mining Equipment, Queensland
Used the selection checklist to specify heavy duty units for a coal conveyor upgrade. Service factor 2.25, ductile iron housing, FKM seals, synthetic oil, EN 10204 2.2 material certificates. All parameters correctly specified first time — no back-and-forth revisions. “Having the complete checklist meant we gave Ever Power exactly what they needed and got the right units back exactly once.” — Senior Mechanical Engineer
Germany — Food Processing OEM, Cologne
Completed the checklist including food-grade requirements (IP65, NSF H1 oil, stainless output shaft). Ever Power returned a specification confirming all parameters were achievable with standard lead time. CE documentation from the Netherlands entity was accepted by the end customer’s food safety audit team without further action. “Complete specification, complete documentation, on time. That is all we needed.” — Procurement Manager
FAQ
Ready to select your right angle spiral bevel gearbox?
Send Ever Power your completed checklist data — or as much as you have. Our Netherlands-registered engineering team returns a matched specification, drawing, and quotation within 48 hours. CE certified. Standard and custom. Global delivery.
