Deburr THEN Dimple?

[OldAndBold]

I am finally back to work on the empennage. I am about to dimple the skeleton. My question,

The instrutions say deburr then dimple. That leaves a slightly rough edge on the dimpled piece. Do I need to deburr the dimpled piece again?

Thanks

John Babrick

[jsharkey]

No.
Deburring is mainly to remove big burrs, lumps and bumps that would otherwise stop mating parts from fitting together snuggly. It also helps to cut out any crack tips at the root of a burr that might propagate into a bigger crack by fatigue - but that's a secondary benefit. Reaming a hole to final diameter helps here too but isn't needed for our applications. Be careful not to deburr too much and open up hole edges unnecessarily.
Jim Sharkey

[jim]

Hi John,

On the Orndorf videos, George recommends a "very light" deburring after dimpling. I have done this and compared to areas where you did not do the second debur, and the rivets are more flush in the ones you debur again after the dimpling. You really need to be careful that you don't overdo it though. He said people have a tendency to remove too much metal with deburring, and to use a light touch. Hope this helps.

[RScott]

If you are going to prime, running Scotchbrite over the dimple will take down most of the roughness.

Dick Scott
RV-9A Wings