I just finished the oil access door in the top engine cowl. It turned out to be more of a chore than it looked at first. I cut the hole close to the scribe line with a Dremel tool and reinforced cut off wheel. I used a sanding block with 60 grit sand paper and rat-tail file for the corners to finish to the scribe line. I like the Dremel because you can start with a plunge cut without having to drill holes. Finishing to the scribe line could be done with Dremel sanding disks, but I like a sanding block to maintain staight edges.
My goal was to have the door centered in the recess. Once the hinges were riveted and hardware installed, I found the door would not open. This was a two-fold problem. First, the aft hinge was binding on the aft edge of the hole. Trimming 1/16" from this edge solved the problem. Second, the top edge of the recess was catching on the door. Beveling that edge seems to have solved that problem. No metal was removed from the door edges other than deburring and modifying the radius of the corners to match the recess.
I drilled the 1/2" holes in the door for the Camlocs, but I think a 7/16" hole would look better.
A word about the Dremel cut off wheels. I would avoid the standard wheels with the small hole in the middle as they will shatter easily sending shrapnel flying. Just ask Marty, BigJohn and myself. The reinforced wheel we refer to has a fiberglass grid embedded in the wheel and the center hole has a metal, butterfly shaped center hole. This wheel requires a special spring loaded mandrel which is sold separately. BTW they sell wheels for wood, plastic and tile that use this same mandrel. I bought mine at Lowes, though they should be found where ever Dremel tools are sold. These wheels may be safer, but you should still wear your safety glasses.
Art Pennanen
My goal was to have the door centered in the recess. Once the hinges were riveted and hardware installed, I found the door would not open. This was a two-fold problem. First, the aft hinge was binding on the aft edge of the hole. Trimming 1/16" from this edge solved the problem. Second, the top edge of the recess was catching on the door. Beveling that edge seems to have solved that problem. No metal was removed from the door edges other than deburring and modifying the radius of the corners to match the recess.
I drilled the 1/2" holes in the door for the Camlocs, but I think a 7/16" hole would look better.
A word about the Dremel cut off wheels. I would avoid the standard wheels with the small hole in the middle as they will shatter easily sending shrapnel flying. Just ask Marty, BigJohn and myself. The reinforced wheel we refer to has a fiberglass grid embedded in the wheel and the center hole has a metal, butterfly shaped center hole. This wheel requires a special spring loaded mandrel which is sold separately. BTW they sell wheels for wood, plastic and tile that use this same mandrel. I bought mine at Lowes, though they should be found where ever Dremel tools are sold. These wheels may be safer, but you should still wear your safety glasses.
Art Pennanen
