Machining information is for sealed bearing journal box for 90 Ton Mikado.  Drawing reference is 282_11DASB
Other machinists may have better tools and ideas to obtain same results.  This method has been successful for me.
Machining information is for advice only.

     
Step 1.  Cut material slightly oversized to allow part to be machined down to size.  Face and square sides to outside dimensions specified in print.  Should have a 2.5" X 2" X 1.385" machined part.

Step 2.  Two Different methods available.  (milling method shown)

A.  Lathe method.  Use four jaw chuck setup, indicate center of work piece, drill pilot hole, then work your way up to a 3/4" drilled hole through casting.  Use boring bar and complete the machining for the journal bearing hole.  Then go to step 3 for milling application.

B.  Milling machine method.  My preferred method.
Indicate center of work piece.
      
Center drill                                 Pilot drill                             3/4" drill                                   Boring head/adapter/boring bar

Work your way up to a 3/4" Drilled hole.  3/4"  hole allows use of boring bar


Finish hole so OD of bearing will fit.


Step 3.
Mill top of journal box for spring saddle fit.

  


Step 4.Mill slot in journal box for fit with frame thickness.

Starting cut for slot opening can be from .234 or the .455 dimension.  The frame should be near the .687 thickness.  Clearance is needed for the slot and should be in the .005 to .009 range or the actual machined slot dimension should be in the range of .693 to .697.  The reason for this is to allow a little movement so the journal does not bind in frame.  This is the basic starting slot before machining the arcs.

    


Step 5.

 
Set-up the rotary table for the machining of the Radius arcs for journal slot.  The Radius of Arc does not have to be precise.  Just as long as they are equal on both sides and are between a 5 to 10 inch radius.  The reason for the radius arcs in part is to allow the wheel/axle/bearing assembly angled motion when traveling down uneven track.  The arcs also help prevent binding of journal box.


Step 6.

    Debur your part and check for fit.  Repeat process until the journal fits smoothly into frame without bind.  May shim if necessary.


Finished journal box.

Page information is for advice only.  Other machinists may have better tools and ideas to obtain same results.  This method has been successful for me.
 

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