With the design finalised, and cash save up I spent £75 on the X bed for my CNC router. This is a 15mm thick plate of aluminium that is 350mm x 600mm square. I needed to drill holes to fit the linear bearings that make up the X axis. These holes need to be VERY accurately aligned and so…
I printed a full scale diagram of the axis on the A0 plotter at the ‘space.
This was printed on modern vellum; a plastic film that is dimensionally stable. Vellum is super accurate and does not suffer from smudging.
Using spray mount glue I stuck this print onto the plate.
Then using an optical centre punch I was able to accurately mark the centres of all the holes. This kind of punch has a ‘crosshair sight’ that allows very accurate alignment with
the drawing. Once the crosshairs are aligned, the sight is replaced with a punch that when struck, accurately marks the work piece.
Once marked, I then confirmed the centres using a spotting drill. This is a drill with the cutting faces at 90 degrees as opposed to the normal 60 degrees. This means it centres more readily in a small hole such as that made by a centre punch.
Once marked, I called in a favour at the mechanical department at work and they drilled the plate on the Bridgeport vertical milling machine.
Here is the X axis completed, with stepper motor and ballscrew.