Step 1: Gathering Parts
The chassis is made of 1/2" sheet aluminum. The bearings are pillow block bearings. The Main(RA) shaft is 2-5/8" diameter aluminum and the smaller(dec) shaft is 1-1/6" steel. The large worm gear was purchased cheaply from an astronomy website.
Step 2: Routing aluminum
Step 3: Basic chassis assembly
I added a brace and tapped a hole for an adjustment bolt. Turning this bolt allows the angle to be adjusted then clamped down when it's right.