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Park Tool Co.

5115 Hadley Ave. N.,  St. Paul, MN 55128 (USA)  www.parktool.com

DT-1.2 

Disc Brake  

Mount  Facing Tool

The Park Tool DT-1.2 Disc Brake Mount Facing Tool is a precision 
tool system designed to machine disc brake mounts flat, parallel, 
and in the same plane. Use of the DT-1.2 helps ensure proper disc 
brake setup and performance. 

The DT-1.2 works on forks with 100mm open dropouts and forks 
with closed dropouts using 20mm thru axles. Works on frames 
with 135mm open dropouts and frames with closed dropouts 
using 12mm thru axles in 135mm, 142mm, 150mm, 157mm and 
160mm lengths.  

Always wear safety glasses when using the DT-1.2.

INSTRUCTIONS

Read instructions completely before using the DT-1.2 Disc Brake 
Mount Facing Tool. Additionally, we recommend contacting the 
manufacturer of frame or fork for specific recommendations, 
cautions, or warranty issues before facing disc brake mounts.

  A.   Determine the frame or fork axle size and spacing, and as-

semble DT-1.2 as shown (Figure 1).

  B.   Install axle of assembled DT-1.2 fully into frame or fork 

dropouts.  For 9mm and 10mm axles, tighten axle mount-
ing bolts (ref. #1). For 12mm and 20mm  thru axles, tighten 
quick release, axle mounting bolts or pinch bolts provided 
with bike (Figure 2).

  C.   Loosen knob set screw (ref. #8). Slide knob (ref. #9) to end 

of facing cutter shaft (ref. #7), next to 10mm hex. Tighten 
knob set screw.  

  D.   Loosen pinch bolt (ref. #12) and pivot bolt (ref. #10) just 

enough to allow axle body (ref. #5) and cutter body (ref. 
#6) to pivot and slide on axle. 

  E.   Slide body against retaining ring (ref. #3) or bushing (ref. 

#14 or #15).

  F.   Insert cutter (ref. #7) through lower hole of body. Insert 

piloted tip of cutter fully  into hole of brake mount.

  G.   Tighten pinch bolt and pivot bolt to lock position.

  H.   Turn knob clockwise while applying hand pressure to face 

surface of brake mount. Remove only enough material to 
create a clean, flat cut around the face of the mount. NOTE:  
For speed and leverage, a ratcheting wrench with a 10mm 
socket can be used to turn the 10mm hex head on the cutter.

  I.   With teeth of cutter contacting face of brake mount, 

loosen knob set screw and slide knob on shaft of cutter 
until contact is made with body. Tighten set screw. 

  J.   Pull knob and cutter from lower hole and insert through 

upper hole. Loosen pinch bolt and/or pivot bolt to fit piloted 
tip of cutter fully into hole of brake mount, then retighten.   

  K.  Note position of cutter teeth.  
         a.   If cutter teeth contact brake mount and there is gap 

between knob and body, complete step L and stop.  

         b.   If knob contacts body before cutter teeth contact brake 

mount, OR, if knob contacts body at the same time 
cutter teeth contact brake mount, skip step L and go 
straight to steps M through Q.

  L.   Turn knob clockwise while applying hand pressure to face 

surface of disc mount. Continue facing mount until knob 
stops against body. The facing process is complete.  The 
upper and lower mounts should have a clean, flat cut 
and the faces should be parallel and in the same plane.  
Remove DT-1.2 from frame. 

  M.   Loosen knob set screw and position knob at end of cutter 

shaft, next to 10mm hex. Tighten knob set screw.  

  N.   Turn knob clockwise while applying hand pressure to face 

surface of disc mount. Remove only enough material to 
create a clean, flat cut around face of brake mount.  

  O.   Loosen knob set screw and slide knob on shaft of cutter 

until contact is made with body. Tighten set screw. 

  P.   Pull knob and cutter from upper hole and insert through 

lower hole. Loosen pinch bolt and/or pivot bolt to fit tip of 
cutter into hole of brake mount, then retighten.  

  Q.   Turn knob clockwise while applying hand pressure to face 

surface of brake mount. Continue facing mount until knob 
contacts body.  The facing process is complete. The upper 
and lower mounts should have a clean, flat cut and the 
faces should be parallel and in the same plane.  Remove 
DT-1.2 from frame.

NOTES:

  

Being a precision cutting tool, the DT-1.2 should be used and 
stored with extreme care. Always liberally apply cutting fluid (we 
recommend Park Tool CF-2 Cutting Fluid) to the brake mount and 
cutting teeth of the facer during each use. Components should 
be kept clean and the facing cutter should be periodically wiped 
with an oily cloth or rust inhibitor before storage, especially in 
a damp or humid environment.  Store the DT-1.2 in its original 
packaging or other safe location. Like all cutting tools, the facing 
cutter included with the DT-1.2 should be periodically replaced or 
sharpened by a qualified technician. Park Tool offers a shapening 
service that returns cutters to factory specifications. For informa-
tion: www.parktool.com

Some disc brake systems require the use of an adapter to 
secure the caliper to the frame or fork mounts. If the DT-1.2 
machines a smaller contact area than the contact area of the 
adapter, the brake may require the use of spacing washers.

For additional instructions and images, visit: www.parktool.com 

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