What mounting positions are available for an NMRV worm gearbox?

Common positions include B3, B6, B7, B8, V5 and V6.

What is the most common NMRV mounting position?

B3 is a common horizontal position, but the correct choice depends on shaft direction and machine layout.

Can an NMRV gearbox be installed vertically?

Yes. V5 and V6 are common vertical arrangements.

NMRV Worm Gearbox Mounting Positions: Which One Should I Choose?

Q: Does mounting position affect lubrication?

Yes. Oil quantity and breather, oil-level and drain plug positions can change with orientation.

Q: What information should I provide when ordering?

Provide NMRV size, ratio, motor details, mounting position, output direction and an installation drawing or photo.

Published September 18, 2026 · SMK Transmission technical guide

Buyer answer: Choose the NMRV mounting position from the machine layout, shaft direction and motor orientation. B3, B6, B7, B8, V5 and V6 use different plug and lubrication arrangements, so confirm the position before ordering.

NMRV worm gearbox mounting positions B3 B6 B7 B8 V5 and V6

What mounting positions are available?

Common NMRV positions are B3 horizontal, B8 inverted horizontal, B6 and B7 side mounting, and V5 and V6 vertical mounting. The correct choice depends on the machine frame, shaft direction, motor position and clearance.

How should I choose the position?

B3: standard horizontal mounting.
B6 / B7: side mounting for left- or right-facing output.
B8: inverted horizontal mounting.
V5 / V6: vertical mounting with the motor above or below.

For a new conveyor, packaging line or mixer, draw the input and output centerlines first, then match the gearbox position. See the NMRV worm gearbox range.

Does mounting position affect lubrication?

Yes. Oil level, oil quantity, breather plug and drain plug positions can change when orientation changes. Do not simply rotate a gearbox and assume the original oil level remains correct.

Installation check: Confirm the breather at the designated upper position, verify oil level for the selected orientation, and keep the drain accessible. Follow the model drawing before commissioning.

Can the position be changed after delivery?

Often the housing supports more than one position, but lubrication and plug locations must be rechecked. Also verify motor terminal-box orientation, flange clearance and shaft alignment.

What information should I provide when ordering?

NMRV size and ratio
Motor power, voltage, frequency and speed
Input and output shaft directions
Mounting position: B3, B6, B7, B8, V5 or V6
Output bore and mounting dimensions
Application, duty cycle and required torque

Compare the RV63 guide, RV75 guide and RV90 guide. For conveyor sizing, see the conveyor gearbox page and ratio and torque calculator.

Conclusion

B3 is a common horizontal position, while B6, B7, B8, V5 and V6 solve different shaft and layout constraints. Confirm mounting, lubrication and plug arrangement together before purchase. Send SMK your drawing or installation photo for a configuration check.