There are times when a pin router would be handy, and a radial arm saw provides a handy platform with its arm adjustable for height and the motor carriage that can be locked at any position along the arm. And, if necessary, the motor can be tilted for very special needs.
Some radial arm saws, like Sawsmith and Montgomery Ward's Powr-Kraft, came from the factory with a high-speed spindle on the right end of the motor for a router collet chuck. The Sears radial arm saws have a spindle with 1/2 inch thread for a Jacob's Chuck. The Sears spindle runs too slowly for use with a router bit.
Step 1: Mounting holes
This Sears radial arm saw came with two threaded holes on the bottom of the motor. The holes were used to secure the motor in the crate for shipping. The holes are 5/16 inch by 18 threads per inch.