What tool(s) to debur the WD-1002 and 1003 on the firewall?

What tools or techniques are you using to get into the roughly 2 inch space between the upper and lower wings of these metal mounts after final drilling in section 29?

There are some huge burrs I need to clean up but the standard avery hand operated debur tool with a countersink head on it is too long and just using the head only, like I've done in other tight quarters, would be tough on steel.

20/20 hindsight, I would not have riveted these to the firewall until after this step. Then I could just use a small grinding wheel in a drill to clean the inner faces and then had the parts cleaned and powdercoated before riveting to the firewall and proceeding with the post-longeron assembly. In the event, I used a grinding point instead of a wheel and touched up where necessary.

Just finished that part of section 29. I assume you are referring to the steel burrs? I ran a file down over the burrs to knock them down. It’s steel and I don’t think it’s as critical to debur as aluminum. My02 worth

Keith