Whatever matches the screws on the right.![]()
If i may suggest additional: Cut a small thin plastic disc (maybe around 20mm diameter and 1mm thick) and drill it the threading size (or one drill above, whatever you have available) in the middle. Put this on the screw before chucking it in the drill.
That will minimize the risc of having the file getting into the drillchuck.
Some may find working that way more safe than without. Esspecially if you are not that used to work with fast rotating machineparts.
Starting to look like something finally.
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