< Axle Driven Pump Straps >
Eccentric straps of the axle driven pump are made from gunmetal casting bodies and laser cut arms. As usual, the castings were cast with homemade patterns by Modela. I prepared them when preparing the castings for the Hunslet.
Clean the casting's both faces parallel in three-jaw. Finish a face, reverse and chuck parallel using the jaws' steps.
Separate two halves by a metal saw. Note two holes for assembly are opened beforehand. The half length of the holes are threaded.
Metal-sawed surface is not so clean, so I finished the cross sections with a fly cutter. It makes the cross sections truly vertical to the side faces.
Assemble the strap bodies with screws and finish the bore in the lathe. Note a disk is glued onto the strap in order to scribe the center for centering with the wobbler.
The bore is finished to the designed diameter. Fitting work will be done by adjusting eccentric sheave's diameter.
Cut a slit at the back in order to fix the laser cut arm. It was done with a small end mill.
Open a screw hole for a nipple of lubrication in the strap shoulder. The large screw hole is stopped in a middle and connected to @mm thin through hole.
Assemble whole parts with screws. The strap back body and the arm is fixed permanently. So I utilized Loctite 222.