Thu Apr 23 2009

Drilling engine mount to firewall

First task for tonight is to drill out the two rivets that hold this spacer block to the aft half of the center section bulkhead. I ordered some 5/32 rivets last night along with some long flush head screws. I figure I'll drill the block up to 5/32 and countersink for the rivets. If I'm unable to get those to set correctly I'll just screw the block on. Why's it always the little things that cause the most problems?

After match drilling and countersinking the replacement parts, I decided to drill and ream the bottom left hole of the engine mount to the firewall. One good thing about the previous screwup is that I didn't have to drill through the stainless steel this time. That made for smooth going during both the drilling and reaming operations.

The hole came out great. You can see that the stainless is somewhat elongated, but that's perfectly acceptable and it'll be covered by the flange on the engine mount as well. All I have to do now to get this thing back into shape is drill the holes through the ears of the weldment that attach the weldment to the longeron and gussets. The vertical stiffener on the side of the firewall also gets one hole match drilled. It's the hole which attaches the forward end of the forward fuselage stiffener to the firewall stiffener.