Products Power Transmission Products

  • Timing Pulleys

Fit Bores

Fit Bore Timing Pulleys can be ordered just by the model number because shaft bore, key, and tap processing are standardized.

Quick delivery of timing pulleys with finished bores.

Available products

Finished Bore Type (Immediate shipment)
P5M, P8M
Easy Finished Bore Type (Quick delivery)
P5M, P8M, P14M, XL, L, H
Fit-Bores picture

What is Fit Bore?

We have created codes for the different types of finishing for easy ordering by model number.
Customers do not need to create drawings when ordering. We can also issue drawings for confirming specifications.
We deliver products quickly. After a product arrives, it can be used as is.

Available model list/detail

PX Pulley

Name Pitch (mm) Materials
P5M 5.00 Carbon steel: Carbon steel for machine parts
P8M 8.00 Carbon steel: Carbon steel for machine parts

Trapezoidal Tooth Pulley

Name Pitch (mm) Materials
XL 5.080 Carbon steel: Carbon steel for machine parts
L 9.525 Carbon steel: Carbon steel for machine parts
H 12.700 Carbon steel: Carbon steel for machine parts

Finishing Bore Type

Finished Bore types have standardized shaft bore, key, and tap finishings. You can order this pulley for immediate delivery with just a model number.

Easy Bore Finishing

Bore finishing (L) Keyway finishing (K) Tap hole finishing (D)
Bore finishing fig. Keyway finishing fig. Tap hole finishing fig.
  • Finishing dimensions are whole numbers in 1mm units
    *No inch sizes available
  • Finishing tolerance: Choose from the following
    H7, G7, M7
  • Follows JIS standards for keyway width and height
    Parallel keyways only
  • Finishing tolerances: Choose from the following
    Js9, P9, F7, E9
  • Tap sizes to match bore diameter
    Up to two (2) hole locations
  • Areas to finish: Selectable
    One: 1
    Two: 2
    Two: 3

Plus, surface treatment electroless nickel plated *Additional processing parts are not plated.

Contact a Tsubaki representative for orders of ten or more.

Model numbering

Sample model no. Pulley model no.
Finishing code Bore tolerance Shaft bore diameter キー溝公差 Tap hole finishing Surface treatment
-H 50 J 2 K
  • H: H7
  • G: G7
  • M: M7
Shaft bore diameter mm
  • 「-」: No
  • New JIS J: JS9, P: P9
  • Old JIS F: F7, E: E9
  • 0: No
  • 1: One location, on the keyway
  • 2: Two locations, on the keyway+90°
  • 3: Two locations, on the keyway+120°
  • Blank: No surface treatment
  • K: Electroless nickel-plated

In the examples above, the model no. and bore finishing code would be P30P8M15AF-H50J2K.


  • Keyway and tap follow JIS standards. Customers should check whether they can use this under their usage conditions, or contact a Tsubaki representative.

Finishing type (Tap finishing position)

AF Type

AF Type Tap finishing position fig.

BF Type

BF Type Tap finishing position fig.
  • With AF types, the tap finishing angle of the 2nd hole is an approximate angle (since it is processed on the pulley's tooth valley).
  • Some holes may be counterbore holes when they are long.
  • Finished taps come with set screws for each tap hole.

Set screw specifications

  • Hexagonal head, hollow top type, and made of steel.
  • If the body is plated, set screws will be attached.
Set screw specifications