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match drilling rudder skins

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woodsideraff

Well Known Member
I am using a #41 reamer to match "drill" the skins to the inner ribs. I notice that the holes on the skins and ribs in the rudder are already the right size. The rivets go in without match drilling.

I cannot find in the instructions a step for match drilling the skins to the ribs. Is this new for the -14? In the -7 we had to enlarge all the holes.

Any comments?

Cheers,

Rafael
 
For the most part, RV-14 builders will only have to match drill when the construction manual says to (there is bound to be a few instances that got missed).
 
I'm using a #40 reamer. Should I be using at #41? Additionally this may be semantics but I have thought "match drilling" meant that you were drilling through a hole in one piece into a hole in another piece "matching" the hole and "final drilling" was reaming out a hole to the correct size.

Also for what it is worth the #40 reamer will not go through the pre punches in the rudder skins.
 
HeliCooper said:
I'm using a #40 reamer. Should I be using at #41? Additionally this may be semantics but I have thought "match drilling" meant that you were drilling through a hole in one piece into a hole in another piece "matching" the hole and "final drilling" was reaming out a hole to the correct size.

Also for what it is worth the #40 reamer will not go through the pre punches in the rudder skins.
Click to expand...

OK, let's call it "final drilling", we know what it is.

Around 2006 (can't recall the year right now) I attended a workshop in Griffin, GA where I built the tail feathers for my -7A project. I was instructed to use a #41 reamer to enlarge the holes for 3/32" rivets. It does produce a tighter fit besides showing how good a job you have done fluting the ribs.

In our -14, I can slide the rivets into the punched holes in the clecoed assembly without enlarging them. I don't have a #40 reamer, but I can slide a #40 drill shaft into the assembly. Thus, I surmised that the holes in the 14 are already the right size.

Cheers,

Rafael
 
You are correct about match drilling and final drilling. I think that's what he meant to say. I was also told you shouldn't have to final drill any of the wing skins.
 
Like I said it was semantics. More for me to make sure I am on the right page. Sorry.

Follow up question. So with this new knowledge on 7-02 they have you deburring all the stiffeners, horns, etc after you cut them out. I left all the holes assuming I would have to final drill them later but it sounds like I can go ahead and even debur all the holes at that time as well?

Thanks for the patience for the new guy.
 
woodsideraff said:
OK, let's call it "final drilling", we know what it is.

Around 2006 (can't recall the year right now) I attended a workshop in Griffin, GA where I built the tail feathers for my -7A project. I was instructed to use a #41 reamer to enlarge the holes for 3/32" rivets. It does produce a tighter fit besides showing how good a job you have done fluting the ribs.

In our -14, I can slide the rivets into the punched holes in the clecoed assembly without enlarging them. I don't have a #40 reamer, but I can slide a #40 drill shaft into the assembly. Thus, I surmised that the holes in the 14 are already the right size.

Cheers,

Rafael
Click to expand...

Tolerances and drilling accuracy come into play here.

A 3/32 AN rivet is 0.094 +0.003/-0.001 = 0.093 to 0.097

A #41 drill is 0.096, so some of your rivets might be a tight fit in a good #41 hole...:)

A #40 drill is 0.098

However, dimpling opens up the hole size, so I prefer a #41 drill for dimpled holes, and a #40 if the holes are not dimpled.

I also think the rivets fit a little better (less squeezing) in a #41 dimpled hole.
 
az_gila said:
Tolerances and drilling accuracy come into play here.

A 3/32 AN rivet is 0.094 +0.003/-0.001 = 0.093 to 0.097

A #41 drill is 0.096, so some of your rivets might be a tight fit in a good #41 hole...:)

A #40 drill is 0.098

However, dimpling opens up the hole size, so I prefer a #41 drill for dimpled holes, and a #40 if the holes are not dimpled.

I also think the rivets fit a little better (less squeezing) in a #41 dimpled hole.
Click to expand...

Doesn't the priming also add a little, so the rivets would be a tight fit, even with the #40? I had used a #40 reamer for final drilling and after I primed my ribs, some of the rivets were really tough to get in. Whatever way works best for you, they all seem to meet standards. I have become such good friends with order entry, I only have to give them my first name now and not my builder number. I told them they should just keep my credit card on file.
 
jswareiv said:
Doesn't the priming also add a little, so the rivets would be a tight fit, even with the #40? I had used a #40 reamer for final drilling and after I primed my ribs, some of the rivets were really tough to get in. Whatever way works best for you, they all seem to meet standards. I have become such good friends with order entry, I only have to give them my first name now and not my builder number. I told them they should just keep my credit card on file.
Click to expand...

Priming should be in the order of 0.001 thick, and effectively would be much less inside a hole due to the angle of the spray gun fan.

It also depends if you prime before or after drilling...:)

If it's after drilling, then I think the dimpling action would open up the hole more than priming would fill it - unless you are slathering on the primer too thick.
 
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