SonexBuilders.net

When planning for the AN-3 bolts in the rear spar angles should I plan on reaming the holes, or can I just use a 3/16 inch drill?

By the way, I'm really impressed with the quality of the kit. Will be flush riveting and enjoying every minute.

Thanks

Ed, a 'newbie' just east of Graceland

I think it's worth spending a bit of extra money on a reamer. There are many AN3 bolts in the Sonex airframe. They are all loaded in shear so good fit is important and some of them are critical parts. Not only that, but if you are going to enjoy flush riveting you'll love installing bolts that are a really neat push-in, or even light tap-in fit.

Peter

I don't disagree with Peter, but I'll confess I drilled rather than reamed the holes for all my AN3 bolts. On the other hand, reaming is the only way to go for the main spar holes. All in my opinion of course. Welcome to the gang!

Early in my build I purchased reamers for #30, an-3/4/6 and a couple of others I can’t remember. I also purchased the appropriate drill bits that are just a small step smaller, and put them together in their own case in pairs. Makes it very easy to drill then ream, and the results are very satisfying.

Gordon

Thanks for the quick response!

Now for another question...did you get straight or spiral flute reamers?

Ed

Mine are all straight.

There have been many high quality homebuilt airplanes built without a reamer. But, I have to agree, the results are more satisfying.

I have to fight the urge to be overly perfect. For example - wouldn't all rivet holes look nicer if I drilled them to #31 then reamed them to #30? I have to remind myself not to let better be the enemy of good. If something is safe and proven, that is all you need.

Bryan Cotton wrote:I don't disagree with Peter, but I'll confess I drilled rather than reamed the holes for all my AN3 bolts. On the other hand, reaming is the only way to go for the main spar holes. All in my opinion of course. Welcome to the gang!

That goes for me, too. I suspect the vast majority of flying Sonexes don't have reamed holes for anything other than the spar holes. If reaming makes you feel good, go for it. But a 'famous' aircraft builder once noted, "you're not building a Swiss watch." :-)

samiam wrote:There have been many high quality homebuilt airplanes built without a reamer. But, I have to agree, the results are more satisfying.

I have to fight the urge to be overly perfect. For example - wouldn't all rivet holes look nicer if I drilled them to #31 then reamed them to #30? I have to remind myself not to let better be the enemy of good. If something is safe and proven, that is all you need.

A friend of mine has done almost exactly that. He is building a Xenos and is VERY particular about build quality. When he was assembling the wing leading edges he drilled the holes that are to be dimpled to 3/32" and then dimpled them with a good quality commercial dimple set, after which the hole had enlarged to nearly 1/8" - close enough to be able to fit 1/8" Clecos. He then reamed the holes to 1/8" (not #30) before riveting. Running a reamer through is no more work than drilling. The benefit was that he didn't have a single case of the rivet tail pulling through too far. By comparison, I drilled the holes and had 20 to 30 rivet tails pull through too far on each wing. I had to very carefully grind off the protruding tails. He actually saved time by reaming the holes and is happy with the job. I'm hoping to see him tomorrow to judge for myself but if he is happy, it must be good.

Peter

Grinding off rivet tails.............This debate over reaming #30 holes or drilling #31 holes is starting to sound like the "primer debates" on the Vansairforce.net.

I am near the end of my Onex build. I have a pre-owned kit from 2011 and have had a nightmare with proud rivet stems no matter how loose or tight the hole is, thus spending a lot of time with a dremel grinding off the rivet tails. I had about 50 per cent of both CCC-42's and CCP-42's break off proud..........ugh!

I got low on rivets and bought a bunch from Aircraft Spruce........and surprise.......NO proud stems....zero! And it didn't matter if the hole was a bit oversize or not.

Evidently the batch of rivets that came with my kit was the problem. I threw the rest of the Sonex rivets in the garbage and have had no problems since I made the switch.

Having built a number of RV's previously before this Onex, I think reaming #30 rivet holes is a waste of time. You are "over thinking it". I have seen a number of builders (RV projects) that get so caught up in little details that they "burn out" and never finish the project (10 years into it and only half done).

Keep your eye on the bigger picture......don't sweat the small stuff.

Gordon.......Onex........Hummel 2400