DIY CNC Part 2: Table, Gantry, Bearing Subframes
With the research done, I plan to construct my CNC machine a little larger than what was specified in the MyDIYCNC Comprehensive Plans and Manual. The original plans call for a 10″ x 18″ table with a working surface of approximately the size of a 8.5 x 11 sheet of paper. For my build, I am going to construct it with wood and double the X and Y axis to give a a little larger working surface for the parts I plan to create. The plans call for 1″ aluminum tube but I decided to go with wood as my initial build. If I should encounter problems constructing the table or the gantry, wood seemed like a better and economical option.
I recently found another option for the build after I purchased the wood and constructed the base of the machine. There is a company on eBay selling 80/20 aluminum extrusion already cut to the lengths I need to build my machine. At this point I am going to continue the build with wood and potentially upgrade later.
The parts I am planning to use for this part of the build are:
1 – 2 x 4 x 10
4 – brackets
8- wood screws
1 – 4 x 8 sheet of 1/2 inch plywood
1 – 1″ x 36″ aluminum angle
1- 2″ x 3.5″ aluminum angle
6 – Igus clip bearings, part # MCI-06-02
All the parts were obtained at Home Depot with the exception of the clip bearings. The clip bearings were purchased through Igus.
I cut two 24″ pieces, and two 36″ pieces out of the 2 x 4 I obtained at Home Depot. The end to end dimension on the x axis would be 36 inches. This was done so I could eliminate having to make three additional cuts to the rods I ordered. The steel rods and threaded rods come in 36″ lengths and are used to transport the x table and the y and z carriages. Using a carpenter square and clamps I made sure the “box” was square and screwed the four brackets into position on the inside of the frame.
Once the frame was built, I cut the gantry out of the 1/2 inch plywood following the specs in the MyDIYCNC Comprehensive Plans and Manual. I was able to find a piece of 1/2 plywood marked down 70% at Home Depot and have them cut the plywood into two 6″ strips. Home Depot generally marks down wood if it has some defect and they will provide the first two cuts for free. Although the wood I purchased had a defect in it, I had them cut the two 6 inch strips out of the best part of the wood avoiding the defected ends. Clamping both pieces together, I drilled the holes according to the specs found in the plans.
Once both gantry uprights were cut and drilled, I moved onto cutting and drilling the linear bearing subframes. The subframes are made from the 1″ aluminum angle. Six are needed to transport the x table, y and z axis carriages. Cutting and drilling these in pairs is best in order to keep the parts line up nicely. The subframes were cut and drilled to spec.
To finish the bearing subframes I took a small bastard file and took off any sharp burrs around the frames and around the holes. Once the subframes were finished, I installed the clip bearings into the subframes. The clip bearings are finger pressed into place and care is needed to make sure any burrs from the holes are filed off.
The Z axis NEMA motor mount was built with 2 inch aluminum angle cut and drilled to the specs found in the build plans. I found a small piece of 2 inch aluminum angle at my friends shop when drilling the X, Y, and Z bearing subframes. I took the 2 inch angle, cut and drilled it to spec. The mounting plate will hold the Z axis NEMA motor.
Well that completes the first part of the build. In the next post I will be building the z and y carriage. Below is a link to the aluminum extrusion I found on eBay.
Aluminum extrusion on eBay 80/20