Park Tool Co.
5115 Hadley Ave. N., St. Paul, MN 55128 (USA) www.parktool.com
A properly faced bottom bracket shell is
important for bottom bracket fit and perfor-
mance. The Park Tool BFS-1 is a precision
tool system that provides a piloted means
for cleaning up the two faces of a threaded
bottom bracket shell and making the faces
parallel to each other. The BFS-1 is ideal for
use when a large amount of material is to be
removed, such as when converting a 70mm
bottom bracket shell to 68mm.
INSTRUCTIONS
1) Mount the frame in a Park Tool repair
stand. Always wear safety glasses when
using the BFS-1 or any cutting tool.
2) If the bottom bracket shell width is
to be changed significantly, accurate
measurements should be taken to de-
termine how much material to remove
from each side.
3) Determine the appropriate bushings
to use for the frame's bottom bracket
thread standard. 1.370" x 24 TPI
English bushings are supplied with the
BFS-1. These are marked RH and LH,
which designates the direction of the
threading, NOT the side of the frame in
which the bushing is used. The bushing
marked LH (Ref. #5) is used in the drive
side (the side with the chainrings). The
bushing marked RH (Ref. #4) is used in
the non-drive side. Optional 36mm x
24 TPI Italian bushings are available as
accessories. Both the drive side and
non-drive side of a frame using the
Italian thread standard use a right hand
thread. Two #688 Italian threaded bush-
ings are required for the job.
4) Apply grease to the threads of the bush-
ings and install into the bottom bracket
shell. Start threading the bushings
into the shell by hand to avoid cross
threading. The handle weldment (Ref.
#1) may then be used to turn the bush-
ings until the outer face of each bushing
is installed well below the face of the
bottom bracket shell. Do not force the
bushings into the shell. If resistance is
felt, the bushings should be removed
and the threads of the bottom bracket
shell should be tapped using a BTS-1
Park Tool Bottom Bracket Tapping Set.
5) Slide the facing cutter (Ref. #3) onto
the pilot of the handle weldment and
onto the two pins. Insert the pilot
of the handle weldment through the
bushings in the bottom bracket shell.
Slide the knurled washer (Ref. #6),
the keyed anti-rotation washer (Ref.
#7) and the spring (Ref. #8) onto the
pilot. Thread the knurled tension nut
(Ref. #9) onto the pilot until the spring
begins to compress.
6) Apply liberal amounts of cutting fluid to
the face of the facing cutter. Park Tool
CF-2 Cutting Fluid is recommended.
7) Rotate the handles clockwise to begin
facing the bottom bracket shell. Coun-
ter-clockwise rotation will damage the
facing cutter. Rotate the tension nut
gradually to increase spring pressure,
if necessary. Use only enough spring
pressure to provide a smooth cutting
action.
8) Continue to rotate the handles several
turns, then stop to check progress. If
the objective is to only face the shell,
remove only enough material to ex-
pose a fresh cut completely around the
face of the shell. If the objective is to
reduce the width of the shell, continue
facing until the predetermined amount
material has been removed. Measure
the bottom bracket shell width regular-
ly to avoid cutting too much material.
Due to a combination of factors (the
type of material being cut, the amount
of spring pressure used, the type of cut-
ting fluid used, etc.) "chattering" marks
may appear on the finished surface.
This "chattering" is cosmetic only.
9) When one side of the bottom bracket
shell has been faced, remove the
tension nut and turn the facing cutter
clockwise with light hand pressure to
remove any burrs.
10) Repeat steps 5 to 9 on the second side
of the bottom bracket shell.
11) When both sides of the bottom bracket
shell have been faced, remove the
handle weldment from the shell and
remove the facing cutter from the
handle weldment.
12) Using the handle weldment, re-
move the bushings from the bottom
bracket shell.
13) Rotate the frame so cutting fluid can
drain from the bottom bracket shell.
Remove any metal chips with a rag,
then clean the shell with a brush.
NOTES:
The BFS-1 is a precision tool and should be
used and stored with extreme care. Com-
ponents should be cleaned after each use
and wiped with an oily cloth or rust inhibitor
before storage. Store in a safe place, such as
the original carton.
Metal cutting tools by their nature must be
very hard, and the teeth are in fact fragile.
BFS-1 Bottom
Bracket Facing Set
Even when care is taken to follow correct
procedures, local areas of hardness from
welding or other anomalies can damage the
facing cutter. Like all cutting tools, the BFS-
1's facing cutter will require periodic sharp-
ening. Park Tool Co. offers a sharpening
service that can return cutting tools to factory
specifications. Information can be found at:
www.parktool.com.
BFS-1 TRETLAGERFRÄSER-SET
Die sorgfältig plangefrästen Außenkanten der
Tretlagermuffe sind wichtige Voraussetzung
für den optimalen Sitz des Innenlagers und
seine einwandfreie Funktion. Das BFS-1 von
Park Tool ist ein Präzisionswerkzeug mit exak-
ter Fräsführung für Muffen mit Gewindeauf-
nahmen, das plane und parallel ausgerichtete
Muffenabschlüsse gewährleistet. Das BFS-1
ist das ideale Werkzeug zum Entfernen von
viel Material, zum Beispiel wenn eine Tret-
lagermuffe von 70 mm auf 68 mm reduziert
werden soll.
BEDIENUNGSANLEITUNG
1) Fixieren Sie den Rahmen in einem
Montageständer. Tragen Sie während
der Bedienung des BFS-1 oder anderer
Fräswerkzeuge immer eine geeignete
Schutzbrille.
2) Wenn die Breite der Tretlagermuffe
deutlich reduziert werden soll, sind zu-
vor exakte Messungen notwendig, um
festzustellen wie viel Material auf jeder
Seite entfernt werden muss.
3) Stellen Sie fest, welche Einschraub-
hülsen für die Gewinde der Tretlager-
muffe erforderlich sind. Einschraub-
hülsen mit dem Maß 1.370" x 24 TPI
BSA sind im Lieferumfang des BFS-1
enthalten. Diese sind mit die jeweilige
Gewinderichtung angebenden Marki-
erung versehen, „RH" („right hand" ,
Rechtsgewinde) und „LH" („left hand" ,
Linksgewinde). Diese Markierungen
geben NICHT die Rahmenseite an. Die
Einschraubhülse „LH" (Ref. #5) wird
für die Kettenseite (in Fahrtrichtung
rechts) benötigt. Die Einschraubhülse
„RH" (Ref. #4) wird auf der in Fahrtri-
chtung linken Rahmenseite verwendet.
Einschraubhülsen für Italienisches
Gewinde 36 mm x 24 TPI sind separat
lieferbar. Beim Italienischen Gewindes-
tandard verfügt die Tretlagermuffe auf
beiden Rahmenseiten über ein Rechts-
gewinde. Daher werden zum Fräsen
zwei #688 Einschraubhülsen benötigt.
4) Tragen Sie etwas Fett auf die Gewinde