Tc 9-524 fundamentals of machine tools

Splined Shafts and Fittings
Splined shafts and fittings are generally cut by bobbing and
broaching on special machines. However. when spline shafts
must be cut for a repair job. the operation may be
accomplished on the milling machine in a manner similar to
that described for cutting keyways. Standard spline shafts and
splint fittings have 4, 6, 10, or 16 splines, and
theirdimensions depend upon the class of tit for the desired
application: a permanent fit, a sliding fit when not under
load, and a sliding fit under load. Table 8-8 in Appendix A
lists the standard dimensions for 4, 6, 10, and 16-spline shafts.
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TC 9-524
Milling Splines
Spline shafts can be milled on the milling machine in a
manner similar to the cutting of keyways.
The shaft to be splined is set up between centers in the
indexing fixture.
Two side milling cutters are mounted to an arbor with a
spacer and shims inserted between them. The spacer and
shims are chosen to make space between the inner teeth of the
cutters equal to the width of the spline to be cut (Table 8-8,
Appendix A).
The arbor and cutters are mounted to the milling machine
spindle. and the milling machine is adjusted so that the
cutters are centered over the shaft.
The splines are cut by straddle milling each spline to the
required depth (Table 8-8. Appendix A) and using the index
head of the indexing fixture to rotate the workpiece the
correct distance between each spline position.
After the splines are milled to the correct depth, mount a
narrow plain milling cutter in the arbor and mill the spaces
between the splines to the proper depth. It will be necessary to
make several passes to cut the groove uniformly so that the
spline fitting will not interfere with the grooves. A formed
spline milling cutter, if available, can be used for this
operation.