Tabletop shelf for a workbench

I recently had my first experience of a CNC machine when I got a couple of iTopie 3D printer's MDF frame cut. I learned that irrespective of the amount of material you use, the MDF boards are only sold in fixed dimensions, smallest being 8 feet x 4 feet. So, after the iTopie frame I had 4feet x 4feet MDF board left.

I have had a chronic shortage of space since I started 3d printing and started on my maker journey. I have a 5 feet x 3 feet table that serves as my electronic and 3D printing "workbench". It is very sturdy and I want to modify it instead of buy a totally new workbench (which are very expensive). So I decided to design my own shelving solution for my table, that would fit a 4x4 board. I had the following aims:

1. The shelf will be 'L' shaped and cover a corner of the table.
2. Have at least 2 shelving levels over the top of the table.
3. Standard peg board pattern on the side supports of the shelf (hole distance 1 inch (~2.5cm), hole diameter : 1/8 Inch (~6.35mm) )
4. Experiment with "horizontal" peg board on the shelves themselves. I don't know how useful this would be, but I can think of cool accessories for my bench using these.
5. Leave some space on my table for my 3D printer and filament holder,
6. Atleast an "A2" sized assembly/work area, for my A2 sized cutting mat.
7. Learn how to work with MDF before I start on the actual iTopie build.

Here is what I came up with :

A render of the table top shelf, with peg boards patterns on the side and "horizontal" peg board pattern on the shelves. The back sides are fitted with a 4 mm plywood (Screenshot taken in netfabb Basic).

I designed this in OpenSCAD and exported a DXF file for CNCing. Its sides are 3 feet x 2 feet. Total height is 70cm, the shelf depth and height is ~20cm. All parameters are customizable in the OpenSCAD, including the number of shelves you need and if you want peg board patterns or not.

Here is the github and thingiverse links for the above design. (Github files may be more current).

Broadly, the steps I followed were:

• Sand the boards I received from the CNC shop so they fit nicely with each other. The CNC owner adviced me to make the inserts 0.5mm thinner than the holes so the cut parts fit without sanding. Place the secondary supports between the selves. Its important you have these supports at the corner where the shelf and the side supports meet. This will give strength to the board.

CNC cut two shelf and two side support pieces. These are the main parts of the frame. Secondary supports are not shown in the image.

Fitted the pieces together to see the fit before the actual build.

• Drill pilot holes for the drywall screws. I drilled holes to join two pieces of the board. I plan to finally join the boards using Fevicol SH and the screws. I had 3.5 x 38 mm drywall screws. The depth of the pilot holes need to be 33 mm, around 5 mm shorter than the screw, and diameter should be 3 mm. Any drill machine with a 3mm bit should do, mind you MDF is a tough material.

Really grateful to Ayush (R) for helping assemble and build the shelf.

• Disassemble the whole bench. Now carefully apply glue to the contact sufaces and start screwing the parts. We start from the bottom shelf.

Sorry for the fuzzy pic, here the bottom shelf has been screwed using dyrwall screws (with pilot holes drilled first) and glued together.

The build is complete (almost!!). Weighing down the bench with all the tools used to build the shelf + some gym weights so the glue sticks . 

• After leaving it overnight, I painted the shelf in black using a can of spray paint. Here is the final product.

My work space before installing the shelf.

My work space after installing the shelf and stacking it up with tools.

The workbench with the cutting mat and tools on the side pegboard.

A closeup of the pegboard.

I had immense fun building this project. It is the biggest thing I have build so far, and it has helped me in organize my workplace much better.