#511 Remotor

#511 Remotor
The NWSL instructions recommend gluing the new motor into the chassis with silicon caulk and soldering the motor lead wires to the appropriate places. I don't like installing components that can't be easily removed, so I built a removable motor mount and used 2-56 screws and nuts to attach power wires.
	Glue .030 styrene into the recesses of the chassis where the old motor mounts are located. Let dry and then drill out two holes as large as the holes in the chassis.

From a strip of 1/8" X 1" basswood, cut a piece that fits into the recess of the chassis where the old motor mounts were located. The size is 15/16" X 2". This piece is the cradle base.
	Cut another piece of the 1" stock to 1 1/4" long and 15/16" wide. Glue onto the base, centered. This block is as long as the motor casing. Usually motor mounts allow for some slight movement of the motor. This second piece can be replaced by a softer material such as foam.

Box in the 2nd base piece. Cut two 1/8" square strips the same length and glue on top. Make sure all outer edges are parallel and even. Let these dry and then test fit the motor. The motor lays on a flat side. Lightly file the inside edges until the motor fits. Then cut two pieces of 1/16" X 1/4" stripwood to 15/16" and glue on the ends. The motor should set snugly inside. Make sure that the flywheels are not rubbing any areas of the cradle.
	Since the chassis recess does not have sharp corners, the bottom edges of the base have to be rounded off to fit. Test fit to make sure it lays flat and does not wobble.
	Set the cradle onto the chassis to mark the hole locations. It is critical that the t-nuts are centered in the chassis holes or else the screws won't thread into them. The surrounding wood was carved out to allow the t-nuts to be even with the cradle bottom. CA glue was used on the edges of the nuts. Once these had dried, I filed the bottom of the cradle smooth.
	2-56 screws are used to mount the cradle. A couple of conditions exist: 1) the heads of the 2-56 screws go through the holes in the chassis; 2) screw length has to be just right so they terminate in the t-nuts yet, hold the cradle tight. My solution was to use screws 7/16" long and put hex nuts on them to adjust the length. Three nuts worked well. They are bigger than the holes in the chassis (the chassis holes are stepped, that is the end of the hole toward the bottom is larger than the top end). They keep the heads from going through and allow the screws to tighten.
	The strap is .020 X .250 brass strip and is mounted with two #2 X 1/8" wood screws.
	To make the strap, bend it around the motor/cradle.
	Cut off the ends just above the bottom of the cradle.

Use an Ultra Fine Point Sharpie to mark the location of the holes. Then use a center punch to make an indent for easy drilling.
	Drill with a bit large enough to allow the screws to pass through without needing to thread into the strap.
	Set the strap on the cradle/motor and mark holes on the cradle. Drill these with a bit that will allow the screw to bite into the wood.
	Completed motor mount. Make sure the wires are in the open space between the strap and motor and are not pinched by the strap.
	File off the stub ends of the driveshaft that run in the worm gear. These had flash on one end and this caused the shaft to rub on the chassis.
	Tap a hole in the chassis with a 2-56 tap and install a 1/2" 2-56 screw. Tighten down. While only one screw is needed, I drilled two holes because I didn't know which side I would need for a ground.

Lugs are made out of .020 X .250 brass and soldered to the motor leads and a jumper wire. The truck pickups are drilled and tapped and a 2-56 screw installed from the bottom. The red motor lead and one end of the jumper wire are bolted to one truck and just the jumper lead to the other. The black lead is attached to one of the grounding screws. After this article was completed, I added a lock washer to each screw to keep the nuts tight. I didn't have a small wrench to tighten these nuts so I made a couple. This is described in the next article.
	Completed installation. Chassis runs great! My total investment was between $60-$75.