How TMF Locks on the 30° Thread Flank
TMF locks through a brass pad rather than through the set screw itself. Each screw drives the pad onto the shaft's thread flank at a 30° radial angle, spreading the load along the flank instead of denting the thread crest. The shaft keeps its full section, and the nut can be taken off and refitted.
The full explanation is on the 30° Flank Locking Series page.
Driven by Pin Wrench
Engagement in the face, not the outside diameter
No Thrust Washer or Keyway
Fewer parts, simpler assembly
Ground Contact Surface and Thread
Maximum axial run-out 0.002 mm
3 Set Screws Per Nut
M6 to M10. 8 to 36 Nm max
Where TMF Locknuts Are Used
Bearing Retention in Housings That Leave No Radial Wrench Access
Gearbox and Reducer Shafts Behind a Cover Plate
Rotary Tables and Index Drives
Rebuilds Where the Surrounding Structure Cannot Be Opened Up for a Hook Wrench
Find Your Size(M20 to M200)
Filter DIN flange locknuts by shaft diameter, height, or pitch.
Products in this 30° Flank Locking Series
Grinding
MF
Grinding
Hook wrench · nut exposed
M12×1 to M260×4 · h 14–36 mm
MF is the original 30° flank locknut, ground to 0.002 mm. Use it where the nut sits clear of the housing and a hook wrench has room to work.
BF
Grinding
Hook wrench · nut recessed
M15×1 to M260×4 · h 14–40 mm
BF has a straight outer profile that stays reachable when the housing covers part of the nut, so a hook wrench still has a square surface to seat against. Same locking as MF.
TMF
Grinding
Pin wrench
M20×1 to M200×3 · h 18–32 mm
TMF is driven through holes in its face with a pin wrench (pin spanner in UK and EU practice). It is ground only, with no precision-turned equivalent.
Precision turning
MFZ
Turning
Hook wrench · nut exposed
M12×1 to M260×4 · h 14–36 mm
MFZ is the precision-turned version of MF, with the same envelope and hook-wrench profile at 0.005 mm run-out instead of 0.002 mm.
BFZ
Turning
Hook wrench · nut recessed
M15×1 to M260×4 · h 14–40 mm
BFZ is the precision-turned version of BF, with the same straight profile and hook-wrench access at 0.005 mm run-out.
SFZ
Turning
Open-end wrench · two flats, to M75
M10×0.75 to M200×3 · h 14–32 mm
SFZ has two parallel flats for an ordinary open-end wrench, up to M75 only. It is the only type down to M10 × 0.75, and the type used most in Japan.
Tell Us What You Need. We'll Find the Locknut.
Give us the locknut code you use now and we'll find the NIKKI equivalent.
Describe the job, thread size, space, load, and we'll point you to the right NIKKI series.
Questions About the TMF Locknut
The TMF is the pin-wrench locknut in NIKKI's 30° Flank Locking Series, in metric threads from M20 x 1 to M200 x 3 with 0.002 mm maximum axial run-out. The questions below are the ones buyers ask before a first order.
Contact UsThe maximum axial run-out of a TMF locknut is 0.002 mm. We finish both the thread and the contact surface by high-precision grinding, which is what holds the run-out to this level. TMF is offered in this grade only.
A pin wrench engages the holes in the face of the TMF and turns the nut down against the bearing. The set screws are then tightened in turn to lock it. Nothing has to reach the outside diameter, so the nut works in housings that give a hook wrench no purchase.
Each TMF size lists a catalog maximum per screw in the dimension table, from 8 Nm on the M6 screws of TMF20 up to 36 Nm on the M10 screws fitted from TMF85. Every size has three screws. Tighten gradually and alternately rather than one screw fully first.
Add L to the order code for a left-hand thread (TMF30x1.5P-L) or U for an inch thread (TMF30-U18). Standard right-hand metric versions are ordered by the plain name, for example TMF30x1.5P.
No. TMF is ground only, at 0.002 mm maximum axial run-out. Where a drawing allows 0.005 mm and the cost of the turned grade matters more than the run-out, MFZ and BFZ are the precision-turned types in this series, though both are hook-wrench profiles rather than pin-driven.
No. TMF locks between the set screws, the brass pads, and the thread flank, all inside the nut, so neither a thrust washer nor a shaft keyway is required. Nothing else goes on the shaft, and the nut is reusable if handled properly.