Drive Spindle Pulley
The dimensions for the belt grove are given to suit a 8mm diameter plastic belt and
may need changing for other forms of belt.
Cut a length of 60 mm diameter aluminium 21mm long, fit in the three jaw, face the
end, and bore through at 9mm diameter. Next reverse in the three jaw and face the
Make a 9mm diameter stub mandrel, tapped M8 and mount the blank onto this and turn
the 24mm diameter by 6mm wide boss. Rough out the pulley grove with the parting tool
and finish the right hand side of the grove with a knife tool and the top slide set
at 14°. Remove the pulley, turn, replace on the mandrel and machine the second side
of the grove. Photograph 14 shows a similar pulley that I made earlier but this one
not having a boss, I subsequently made a steel bush for the bore and included the
boss so that I could use this pulley for this application. This may be apparent in
the Photograph. You will need a second pulley but the diameter will depend on the
drive speeds available and the ultimate speeds required, a subject that I will deal
Inner Clamp Ring (21)
This small part is relatively simple but do take measures to ensure the inner and
outer diameters are concentric and the faces parallel, the later point being quite
important as it is a support between the ball race's central disk and the variable
With that finished the parts that make up the spindle are complete and are shown
in Photograph 15. This also shows the Stub mandrel (centre rear) that was used to
hold the body whilst machining the bores in the second end.
Oscillating assembly starts on the next Page.