Covered the 200mm x 320mm x 5mm black acrylic Terry Filter base with a coating of masking tape which will protect against scratching while drilling and allows me to mark up all the holes. After a trial placing of all the Terry Filter components the board was marked for drilling.
The main pcb and the 2 long resistors will be mounted on 1" high ceramic stand offs which require 4mm holes. The completed Terry Filter module will also be mounted on 1" stand offs, 6 in total. With the board marked up I watched the pretty uneventful start of the British grandprix then made my way out to the garage to drill out the holes.
The board was placed on a flat piece of ply offcut for drilling which prevents the drill bit from damaging the back of the acrylic as it emerges.
When drilling lots of varying size holes I find it useful to mark hole diameters on the work. After drilling the masking tape was removed to reveal a pristine piece of black acrylic with clean tidy mounting holes hopefully in the right places.
First trial fit of the components goes well, all holes line up nicely.
Still waiting for some brass bolts and copper lugs to enable the final assembly.
The safety gap ceramic posts are held in place by 65mm nylon bolts that screw through the base and up into threads in the brass balls. I may change to using metal bolts as the nylon bolts flex and do not hold the safety gap assembly as firm as I would like.
Next job is to make the electrical connectors between the pcb, resistors and terminal posts.
Think it turned out pretty good.
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