Insert and scale the central arm.
In the FeatureManager design tree, select Sketch1.
In the PropertyManager, under Blocks to Insert:
Click Browse, go to <install_dir>\samples\tutorial\blocks, select central_arm.sldblk, and click Open.
Under Parameters, type 6 for Scale.
You can insert blocks and
modify the scale, enabling you to use the same block with multiple models.
Click to place the block in the graphics area,
and then click
.

Save the model.