Why goof around with using steel washers that are not all the same thickness. Here is a quick an simple way of spacing out your motor. The base stand off is precision machined from 6061-T6 aluminum. It measures 1" diameter at the base to give a good load bearing on the wood, and necks down to 5/8" in diameter at the motor and has a 1/4' thru hole.  If more length is required, simply add the spacers included to get the desired length up to 7/16" of added length. Kit comes complete with (4ea.of the following) Stand off bases, 1/4", 1/8" & 1/16"

Available in 4 popular lengths

1/2-15/16"

1 to 1-7/16"

1-1/2 to 1-15/16"

2 to 2-7/16"