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
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.

List of models affected/details

  • Standard stock PX Pulleys (P5M, P8M, P14M)
    *Only models made from carbon steel for machine structural use.

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 Finished Bore Types

Easy Finished Bore Types are standard stock pulleys that have been finished by Tsubaki. The shaft bore, key, taps, and surface treatment have been standardized. These models can be delivered quickly thanks to their simple notation.

Finishing specifications

Ordering is easier and more convenient thanks to notation for short delivery and finishing.

Bore Finishing

Finishing range
Shaft bore tolerance Shaft bore diameter Chamfer amount
  • H: H7
  • G: G7
  • M: M7
Three-digit notation
Integer (mm)
  • N: Not specified
    Tsubaki standard chamfer
  • A: 1mm
  • B: 2mm
  • C: 3mm

Shaft bore diameters are finished in 1 mm integers (inch dimensions are not applicable)

Tsubaki standard chamfer is 0.5 mm across the board.

Keyway Finishing

Keyway Finishing image
Keyway tolerance Keyway width


  • J: JS9
  • P: P9


  • F: F7
  • E: E9
  • W: Without keyway
Two-digit notation
Integer (mm)
Without keyway 00

Follows JIS standards for keyway width

Without keyway W00

Hole Tapping

Hole Tapping image
Number of taps and position Tap size
  • 1: 1 location
  • 2: 2 locations right 90°
  • 3: 2 locations right 120°
  • 4: 2 locations left 120°
  • 5: 2 locations left 90°
  • Without taps: D0
Two-digit notation
Integer (mm)
Without taps: M00

Tap size corresponds to bore diameter size

Without taps: D0M00

Surface treatment

Surface treatment image
Blank: No surface treatment
K: Electroless nickel phosphorus plating
*Blank after for no surface treatment.
Note: No nickel plating for additionally finished parts.
  • Contact a Tsubaki representative for orders of ten or more.

Model numbering

Pulley model no.
Sample model no.
Bore Finishing Keyway Finishing Hole Tapping Surface treatment
- H 020 N - J 06 D 3 M 06 - K
- Shaft bore tolerance Shaft bore diameter Chamfer amount - Keyway tolerance Keyway width D Number of taps and position M Tap size - Surface treatment
In the examples above, the model no. and bore finishing code would be


  • 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