Drilling the Heatsink
This operation is much easier when using a pillar drill or a power drill that is mounted vertically in a stand. If using a hand-held power drill, please take care to locate the holes for the triac(s) as accurately as possible. Otherwise the output stage PCB may not be a good fit to the internal mountings of the Schneider box.
On a strip of paper or card, mark where the holes are to go.
For a single output stage, the triac is mounted at the centre of the heatsink, 55 mm from each end.
For a dual output stage, the triacs are mounted 12 mm either side of the centre line.
In both cases, the mounting holes for the heatsink itself are 15 mm from each end.
The mounting holes for the heatsink (15 mm from either end) are drilled in the central "valley" of the heatsink.
Wrap the paper or card around at the correct location and tape the two ends together underneath.
Here, I am about to drill the first of these holes which have a diameter of 3 mm.
Some lubricant for the drill is a good idea.
With the mounting holes drilled in both heatsinks.
The 3 mm hole(s) for mounting the triac(s) need to be one "valley" away from the centre line.
Here, I have moved one of my paper "rulers" up, and one down. The effect is exactly the same.
The remaining hole(s) for the triac(s) can now be drilled
View from the rear with all of the 3 mm holes drilled.
At this stage, I normally deburr all of the holes by hand with a suitable drill bit (eg. 6.5 mm).
I recommend wearing a glove for this operation.
The final stage is to increase the diameter of the central holes to 4mm for a depth of ~3mm.
This is to accommodate the plastic bush which is part of the mounting kit for the triac.
To avoid damaging the fins of the heatsink, I have rested it on some rubber matting.
The completed heatsinks from the rear
