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Oversize Wing Bolts for a 6

I cannot imagine any need for these

The holes were so tight on my RV-6A that I often thought It would be impossible to get the bolts in. The instruction book allows reaming and brute force to get them in and it took all that and sacrificial hardware store bolts with half flats and points ground on the end to get the job done. It was the most physically and mentally challenging task in the whole airplane. If someone offered me larger diameter bolts to install it would have seemed a little silly - at least.

Bob Axsom
 
Not if the factory...

Bob Axsom said:
The holes were so tight on my RV-6A that I often thought It would be impossible to get the bolts in. The instruction book allows reaming and brute force to get them in and it took all that and sacrificial hardware store bolts with half flats and points ground on the end to get the job done. It was the most physically and mentally challenging task in the whole airplane. If someone offered me larger diameter bolts to install it would have seemed a little silly - at least.

Bob Axsom
Click to expand...

...reamed some of the holes oversize 0.016 when they shipped the spars...:)

http://www.vansairforce.com/community/showpost.php?p=326486&postcount=3
 
The issue has been...

The issue has been, some of those people who did not want to use brute force, bought reamers that may have been larger than recommended.

The next thing they noticed is the bolts seemed too loose.

No real bites on this offer yet, just more info, so we will let it ride for a while.

BTW, it was a customer that told me that Vans was no longer carrying them.
 
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GAHco said:
The issue has been, some of those people who did not want to use brute force, bought reamers that may have been larger than recommended.

The next thing they noticed is the bolts seemed too loose.

No real bites on this offer yet, just more info, so we will let it ride for a while.

BTW, it was a customer that told me that Vans was no longer carrying them.
Click to expand...

I don't think Van's has ever carried them...The vendor that manufactures the spars (Phlogiston) would supply oversized NAS bolts on an as needed basis if for some reason they had to oversize a hole.
 
04 splice plate hole 1/64" oversize

I’m getting close to putting the wings on my RV-6A project and I noticed one of the 04 splice plate holes is 1/64" oversize. This spar was delivered pre-drilled and I assembled it per Tony Bingelis instructions in Sportplane Builder magazine May 1993 edition.

The bolts I received with the kit are all standard size NAS1304-30 and NAS1306-30.
  • Van's tech support says they don't have oversize bolts and referred me to Genuine Aircraft Hardware.
  • Genuine Aircraft Hardware's website does not reflect inventory even though it appears to.
  • I called GAH and they will do a search for NAS1304/6604-30X, -31X, or -32X and quote me by email. Turns out GAH is able to furnish what I need, NAS6604-30X.
  • NAS66xx is the new number for NAS13xx. Per GAH there might be minor differences in thread length but not in the case of size 04.

My calculations of the stack of parts and the -30 bolt grip length indicate I can use an .063 washer under the bolt heads. Then I'll use another .063 washer under the nuts and still have threads protruding. If I end up with length -31 I'll put two washers under the nut and if -32 three washers under the nut.

BTW 1 - what nuts: I don't see in the plans what nuts to use but I suppose they are AN365 elastic stop nuts although I bought some MS21042-3 and -4 all-metal stop nuts for the main gear weldment because they have a smaller hex for where space is tight for wrench access.

BTW 2 - grip length and washers:

For reference, AC43.13-1B:

7-37. GRIP LENGTH. In general, bolt grip lengths of a fastener is the thickness of the material the fastener is designed to hold when two or more parts are being assembled. Bolts of slightly greater grip length may be used, provided washers are placed under the nut or bolthead. The maximum combined height of washers that should be used is 1/8 inch. This limits the use of washers necessary to compensate for grip, up to the next standard grip size. Over the years, some fasteners specifications have been changed. For this reason, it is recommended when making repairs to an aircraft, whose original hardware is being replaced, that you must first measure the bolt before ordering, rather than relying on the parts manual for identification. In the case of plate nuts, if proper bolt grip length is not available, add shims under the plate. All bolt installations which involve self-locking or plain nuts should have at least one thread of the bolt protruding through the nut.​

Sounds like a tidy ideal practice when bolts of every dash number are available. Note "should" is not "must". Practically speaking in my situation if the ideal bolt grip length is not available I have to make a judgement call which is IMO having a total of four .063 washers is OK in this case. Where should they go?... I'll take the advice of respondents to this post and put one under the head and one, two, or three under the nut depending on whether bolt length is -30, -31, or -32.​
 
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John: Engineering standard is for only a single washer under the head of a fastener and multiples under the nut when required. There are times though, that engineering calls out something different and the drawing callout overrules the standard.
 
John,

all your reasoning and assumptions here seem reasonable to me. I would recommend one washer under the head, and then however many it takes under the nut. Yes AN365 nuts are fine for the wing bolts. They are in pure double shear, so as long as they are a nice tight fit in the holes, the joint won't "work" and there is little or no impact to having two or three washers under the nut.
 
NAS6604-30X

Thanks gentlemen... turns out I found what I need at Genuine Aircraft Hardware... NAS6604-30X.
.
 
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