Quote:
Originally Posted by MercFE
All of the countersinks came out great... Except one. I can't tell you what I did, nor can I tell from looking at it as the impression of the cage didn't move. But, it appears that I got the countersink to walk somehow, leaving a perfectly oval hole in an HS-902 spar.
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Victor, take a close look at your countersink cutter. I think you will find that the fluted or cutting portion of the cutter extends down onto the pilot/tip. If the material you are cutting is thin enough, and you introduce enough of a side load, the pilot itself can cut and allow the hole to oval out. A scrap piece of metal, clamped to the underside of the flange will provide more material as a guide.