Decided to get a new welding helmet. They now come with removable batteries instead of being welded onto the circuit board so I managed to finish the boring jig.
Set it up and ran a test bore.
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It worked a treat until about 3/4s through whereupon the auger popped out the side.
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Grrrrr however It may work ok if I go in half way from each end.
Tomorrow will see.
Looking down the bore there is a sharply defined kink where it started to deflect.
I think a gun drill may be the final answer or maybe a "D" bit.