F-904/704 Countersinking

Post by **Spike** » Mon Dec 28, 2009 4:07 pm

Hey guys,

For those of us building the A variants of the 9/7, how did you manage to countersink the inside of the bottom flange on the forward 904/704 bulkhead? These need to be double flush so the gear weldment will nest in the bulkhead. I have a small csink cage that will fit, but there is no way I can get it in there attached to a drill.

Spike

TomNativeNewYorker · Post by **TomNativeNewYorker** » Mon Dec 28, 2009 5:35 pm

Sounds like you need a reverse countersunk cutter.

http://www.browntool.com/Default.aspx?t ... ductID=341

If you don't want to buy one for just one hole, maybe a loaner can be arranged.

Post by **bullojm1** » Mon Dec 28, 2009 5:37 pm

Ditch the cage and go freehand! Make sure you use an electric drill on its low speed setting. You can thread countersink bits into the 90 degree drill adapter that Avery sells (don't know about others) if you are having with the drill no clearing.

Post by **Spike** » Tue Dec 29, 2009 12:11 pm

Excellent idea! I went free hand with my pnuematic 90 degree drill. I turned the pressure down to 15lbs or so and just teased it. That worked like a champ!

Ill have pictures later today.

Spike