Back in 2010 I bought the carcass of a CNC router from an older gentleman north of Scranton PA. At the time 3d CAD tools were prohibitively expensive, so I did a lot of 2d design and did a lot of backplotting with inplot.
It was a great way to get better at designing and building both machinery and stuff from plywood. I needed to learn how to type and read G-code, select tools, do feeds and speeds, not set the shop on fire, and lots of machine troubleshooting and design.
A few things I learned:
Thompson rails are expensive, but work great. Don’t cheap out and plan to drill the plain ones, because you’ll spend more in drills and carbide end mills than you would have to get the threaded ones.
Only drive one side of a gantry, and design that side to have a long distance between the bearings. Driving both sides of a gantry is a recipe for binding. If you avoid binding, it adds a lot of error as the gantry walks back and forth along the long axis.
Position your bridgeport so you can hang work off the table or out a garage door if you want to do a long series of holes at regular spacing. Drill jigs are crucial for series of holes at regular spacing.
If you are driving anything that creates a lot of dust or dirt, don’t place your gear racks so the teeth are facing up. They load up with crap and your drive pinion will skip teeth.
If you need to babysit long running CNC jobs, have something else productive to do, even if that’s cleaning your shop. It is a really bad idea to let a new job run for hours unattended, especially on a machine that creates flammable dust. I nearly set my shop on fire leaving to buy lunch. It was very foolish.
Finishing is super important. No one wants to interact with splintery wood or sharp parts. People expect things to be painted. Have a plan to finish your parts, or they will be perceived as amateurish.
Paul Carson Designs 