Grant Erwin:
Many many boring bars have square holes, one at 90=B0 and one at 45=B0.-


None of the boring bars I have seen have holes in them for holding
cutters.

Many of the boring heads I have seen have holes in them for holding
cutters.

I have no need for a tool holder with the adjustment capability of a
boring head for holding single point cutters at right angles to a
spindle. I have need of a holder which can simply hold the cutter at a
right angle to the spindle for simple one-off form cutting.

Boring heads cost five to ten times what fly cutters cost, and I have
no need for the extra features paid for by that difference.