Van's Air Force
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Landing gear bolts
- Thread starter Plummit
- Start date
bret
Well Known Member
yip, I just fixed mine, I went and reamed the holes with a 5/16 reamer for the an 5 bolt, big mistake! I barrowed a piloted reamer, I forget the size, and got a set of oversized bolts, NAS 6605-29X ( this is for my 7A ) and it worked out great! Genuine Aircraft Hardwar has all the parts you will need.
dave4754
Well Known Member
off topic but.....
I have been a member for years and decided to start a new post ... but cant?
Can anyone show me where it tells you how to post? I have searched and searched and to no avail. Why is it not clear how to post a new thread?
I can build an airplane but cant figure out how to post on this forum????
my my my
Dave
I have been a member for years and decided to start a new post ... but cant?
Can anyone show me where it tells you how to post? I have searched and searched and to no avail. Why is it not clear how to post a new thread?
I can build an airplane but cant figure out how to post on this forum????
my my my
Dave
Auburntsts
Well Known Member
Why are you going to close tolerance bolts? Just curious is all.
Plummit
Well Known Member
Thanks Bret, I was hoping to find someone who had done this on a -10 and could just tell me the bolt and reamer to use, being lazy and all... ;-)
Dave, regarding new posts, go to the forum you wish to post in and at the top of the page on the left side is a link titled "New thread". Click that and enter a subject and message.
regards
~Marc
Dave, regarding new posts, go to the forum you wish to post in and at the top of the page on the left side is a link titled "New thread". Click that and enter a subject and message.
regards
~Marc
Plummit
Well Known Member
I found that the existing bolts allowed the MG wheels to move back and forth a fair amount. This was happening inside the top mount where the holes are too large for the bolts. Just a little play translates to a lot of movement out at the wheel.
~Marc
I just installed the main gear a few months ago. My plans (page 46-4) say to drill with a 7.9 mm drill bit and use AN5-24A bolts. Where are you seeing NAS6605-33X?
Correct, I guess what I meant to say was, if you want to go with close tolerance bolts, then use NAS6605-33X.
The reason I went with them, is because I inadvertently used 5/16" bit.
bret
Well Known Member
This is a very common mistake, I was thinking I will do the hole good to make it nice and round with a 5/16 reamer, for the AN 5 bolt, if you do this, it will have too much play, and in my case the wheel axle nut moved forward and back by 1/4 to 3/8 inch. in the plans, it says to use a .311 reamer, I did not see this, and others have missed this also.....now it is tight with no play. actually had to tap the bolt in, very snug!
I can verify when I get home, but I believe it is the (PPRL-.3261) Long Piloted Reamer M42 Cobalt.3261
That reamer will give you a .0012" interference fit.
Richard@Langair
Well Known Member
A reamer that is sized at 0.3261 will not fit a close tolerance bolt. That will fit an oversized bolt. The close tolerance bolt should be 0.312,
Oh good catch. I had it in my head that the holes were out of tolerance already (i.e. drilled with 5/16").
Marc, if you're still within the limits of the nominal size bolt, then I guess my 1/64" oversize reamer will be of no use to you.
Plummit
Well Known Member
Gosh I just don't know. The bolt suggested was a NAS6605-33X. That's an oversized, close tolerance bolt. The X represents a bolt that is .0156 oversize. A close tolerance bolt is max .3112.
I don't know if the builder of my plane drilled the hole with a 5/16 bit as many people seem to do, but the landing gear do move around (back and forth).
What bolts did you use Andrew?
thanks
~Marc
I used a "(PPRL-.3261) Long Piloted Reamer M42 Cobalt.3261" with a NAS6605-33X bolt.
You may want to start by pulling one of your bolts out to see what condition the hole is in. Is this plane already flying, or is it still being built?
If you have the slop in your gear, you're going to need at least the 1/64" o/s. If it's really bad, you may even need the -Y 1/32" o/s.
You may want to start by pulling one of your bolts out to see what condition the hole is in. Is this plane already flying, or is it still being built?
If you have the slop in your gear, you're going to need at least the 1/64" o/s. If it's really bad, you may even need the -Y 1/32" o/s.
Plummit
Well Known Member
OK, here's what I found out:
The NAS6605-33X is the oversize, close-tolerance bolt to replace the stock AN5-24A. This is the first oversize bolt, and the grip is almost identical to the AM5-24A.
If you drilled the gear with a 5/16 drill bit you probably need this size bolt.
http://www.gen-aircraft-hardware.com/viewImage.asp?item=NAS6605-33X&folder=basic
The reamer to use for this bolt is either a PPR3261 or a PPRL(Long)3261. The short reamer is about 3½" long. I don't know how long the "L" version is but I will post it soon.
http://www.gen-aircraft-hardware.com/viewImage.asp?item=PPR-.3261&folder=basic
These are "Piloted" reamers, which means the end it turned down so when you put it through the tube, it serves as a guide to help ream the hole straight.
The hole you end up with will be slightly smaller than the bolt, so you will have an interference fit. How much smaller depends on the bolt: There are min and max dimensions that the bolt must adhere to.
You may need a rivet gun, mallet, or B-F hammer(just kidding) to install these bolts. They have nominal threads on the end so the same lock nut can be used. You may need a different washer on the grip area.
There should be no movement in the joint if done correctly.
~Marc
The NAS6605-33X is the oversize, close-tolerance bolt to replace the stock AN5-24A. This is the first oversize bolt, and the grip is almost identical to the AM5-24A.
If you drilled the gear with a 5/16 drill bit you probably need this size bolt.
http://www.gen-aircraft-hardware.com/viewImage.asp?item=NAS6605-33X&folder=basic
The reamer to use for this bolt is either a PPR3261 or a PPRL(Long)3261. The short reamer is about 3½" long. I don't know how long the "L" version is but I will post it soon.
http://www.gen-aircraft-hardware.com/viewImage.asp?item=PPR-.3261&folder=basic
These are "Piloted" reamers, which means the end it turned down so when you put it through the tube, it serves as a guide to help ream the hole straight.
The hole you end up with will be slightly smaller than the bolt, so you will have an interference fit. How much smaller depends on the bolt: There are min and max dimensions that the bolt must adhere to.
You may need a rivet gun, mallet, or B-F hammer(just kidding) to install these bolts. They have nominal threads on the end so the same lock nut can be used. You may need a different washer on the grip area.
There should be no movement in the joint if done correctly.
~Marc
Last edited:
Plummit
Well Known Member
Today I received a "loaner" reamer (Thanks Andrew!). It's marked .3261. When I measured the grip on the bolts I bought from Genuine Aircraft Hardware, they measured .326 - Using my El-Cheapo digital caliper from Harbor Fright. 
Looks like there might be .0001 space to play with..... I'll post a follow up next week.
regards
~Marc
Looks like there might be .0001 space to play with..... I'll post a follow up next week.regards
~Marc
Plummit
Well Known Member
Last night we reamed the holes out and it became clear why the landing gear was moving around. The holes in the gear tower were "wallered" out (technical aviation term). I probably could have gone to the second oversize on the right gear, but when we got done everything was tight.
Getting to the bolt holes involved some disassembly, but we were able to use a regular air drill on the reamer with bo-lube. We had to jack up each side to take the load off the gear as it moved around some, but in the end, we had to pound the bolts in so I know we made an improvement.
regards
-Marc
Getting to the bolt holes involved some disassembly, but we were able to use a regular air drill on the reamer with bo-lube. We had to jack up each side to take the load off the gear as it moved around some, but in the end, we had to pound the bolts in so I know we made an improvement.
regards
-Marc
I did this
Just read this thread and thought I would share.
When I mounted my gear I had one axle toed out and one in and wanted both slightly in. I set the toed out gear leg in the correct position and temporarily welded in in place. (just a small weld on the top of the weldment). I then drilled an oversized hole thought the gear leg. I then ground off the weld then reamed and put the oversized bolt in place. Now both my gear legs are symmetrical and toed in. I ran this across VANS before drilling.
Just read this thread and thought I would share.
When I mounted my gear I had one axle toed out and one in and wanted both slightly in. I set the toed out gear leg in the correct position and temporarily welded in in place. (just a small weld on the top of the weldment). I then drilled an oversized hole thought the gear leg. I then ground off the weld then reamed and put the oversized bolt in place. Now both my gear legs are symmetrical and toed in. I ran this across VANS before drilling.
