Jeff R

Jeff R

Well Known Member
The plans call for AN4-12A bolts to attach the landing gear weldment to the spar (for the RV-9A). When I started to install the bolts, I found that the end of the bolt did not protude beyond the nut. It didn't even look like it protruded past the nylon. I belive the specs say you should have 2 bolt threads beyond the nut.

Seems like I will need at leat a -13, maybe even a -14, to do that. Anyone else find their bolts too short?
 
Good Catch Jeff...

Jeff R said:
The plans call for AN4-12A bolts to attach the landing gear weldment to the spar (for the RV-9A). When I started to install the bolts, I found that the end of the bolt did not protrude beyond the nut. It didn't even look like it protruded past the nylon. I believe the specs say you should have 2 bolt threads beyond the nut.

Seems like I will need at least a -13, maybe even a -14, to do that. Anyone else find their bolts too short?
Click to expand...
...and thanks for posting it. Although most folks do catch this particular instance, one of the most common things I find on inspections is "short bolts." It's these kinds of posts that make people "look twice."
 
Threads exposed

Jeff R said:
...... When I started to install the bolts, I found that the end of the bolt did not protude beyond the nut. It didn't even look like it protruded past the nylon. I belive the specs say you should have 2 bolt threads beyond the nut.
......
Click to expand...

Jeff.... while I believe the "old" standard was two threads, the latest version of AC 43.13-1b now has it as one thread exposed, perhaps due to the later MS bolts having a shorter threaded length.

"All bolt installations which involve self-locking or plain nuts should have at least one thread of the bolt protruding through the nut."

For an AN-3 bolt, this difference is the thickness of a thin AN 960 washer.

Like Mel, this is one of the most frequent items I spot on inspections, and one of the easiest to fix....:)

The hardware chapter of the AC is here....

AC Hardware chapter

gil A
 
Thanks. I didn't have even a fraction of a thread coming out of the fiber/nylon or whatever it is. I have new bolts on order from ACS. I guess I will go take a look just to see if Van's gave me some of the longer bolts, but I don't recall seeing any.
 
By the end of the project, you will probably choosing bolts by their fit rather than Van's spec. There are several places where an adustment in bolt length or washer thickness is appropriate.

If you are not comfortable with the way something looks, go ahead and make it right.

Vern
 
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