Originally Posted by Scott Hersha
My thinking was that “pre-punched” meant punched slightly under size. “Match drilled” meant drilled to correct size. I might be wrong about that. On my pre-punched kit parts, I used a piloted reamer, in assembly, to open the holes up to final size. Reamed holes are perfectly round, and the reamer leaves very little burr.
My understanding is that "pre-punched" means there are holes there for you, usually undersized. Whether or not they're final sized is up to the piece itself. Most of the 14-specific parts are "final-sized pre-punched" with the 10-specific parts in both "pre-punched" and "final-sized pre-punched" state until the transition to offering only final-sized holes is complete.
"Match drilling" is a completely separate operation that involves drilling a new hole in one or more parts to mate up (match) with another part. Sometimes it's a final-sized match-drill, sometimes it's an under-sized match-drill that gets final-size drilled later.
no matter how you get there, your parts will all be "final-sized" by the time you're ready to dimple and rivet.
I'm building a -10 but here is how I see it:
- 000 prefix (?), it's probably a 14-specific part and final-sized pre-punched
- 10 prefix, it's probably a 10-originating part (except for variations that the 14 gets in the wing) and could go either way depending on DOM.
- 6,7,8,9 prefix, it's designed and spec'd in other models and will (usually) come pre-punched but not final-sized.
- manufactured pieces (angle stock, tubing stock, j-channel), you'll be match drilling.