bob turner
Registered User
Oh, yeah - I missed that in Fobjob's text. No washers!
Question on strut fork bolts
- Thread starter Cooley
- Start date
Steve Pierce
BENEFACTOR
Graham, TX
All I know is that they are in shear and no need to be very tight. I have spent to much time looking at the drawings I guess. Also rebuilt 5 Super Cubs that had never been apart.
Last edited:
acroeric
SPONSOR
Burlington, NC
Several years ago I repaired a ground looped Super Cub. When we removed the wings I found the strut attach fittings elongated. I contacted Piper and got a manufacturer approved repair procedure to ream the holes oversize and install a bushing. The bushings took forever to arrive so I ordered a few extra sets just in case. This particular PA-18 was one of the last ones built and was very low time and I doubt the groundloop had anything to do with the holes. I was surprised to find them like that.
Anyway- my point is that I can get the N# (for the 337) and engineering data and have a few of the bushings if it helps anyone. It was an easy repair but correctly reaming the holes required some thought.
EDIT- Found the engineering order and just added it for future reference.
Anyway- my point is that I can get the N# (for the 337) and engineering data and have a few of the bushings if it helps anyone. It was an easy repair but correctly reaming the holes required some thought.
EDIT- Found the engineering order and just added it for future reference.
Last edited:
Steve Pierce
BENEFACTOR
Graham, TX
I would be very interested in that data and a set of those bushings.
fobjob
MEMBER
Salt Lake City, Utah
Thanks again to tempdoug for sending me the service bulletin that makes clear the strut bolt configuration!
http://www.shortwingpipers.org/photopost/data/509/piper_sb1172a.pdf
too impatient to be a craftsman...
http://www.shortwingpipers.org/photopost/data/509/piper_sb1172a.pdf
too impatient to be a craftsman...
skywagon8a
MEMBER
SE Mass MA6
Shear not tension.
Steve Pierce
BENEFACTOR
Graham, TX
LOL, yes, hadn't had my coffee yet.
Steve Pierce
BENEFACTOR
Graham, TX
The special bolts Piper used were used for a reason, no threads in the shear area and not to long that the gear hits the end of the bolt. I have inspected several Cubs that people have installed standard AN bolts there. I replace them with the correct bolts. Have also been in a field and had to remove the gear to get the wings off when someone used the NAS bolts that Piper called for when they quit making the special bolts and called for installing the NAS bolts upside down so it would not contact the gear in the event of a hard landing. The bolt won't come out when installed upside down without removing the gear.
aeroaddict
MEMBER
Boise ID area
Pardon my ignorance, but why no washers? I did see the change notice that piper removed the washers. CC's originally called for washers on the nut side, but then deleted them.
If bolt grip length is correct then whats the big deal with washers/no washers?
If bolt grip length is correct then whats the big deal with washers/no washers?
Steve Pierce
BENEFACTOR
Graham, TX
The threaded portion of the bolt is very short so that it does not contact the gear. A lot of times if you install a washer you cannot get the cotter pin in.
aeroaddict
MEMBER
Boise ID area
That makes sense. So it's more of an install solution than a 'safe practice' process.
I did notice that I installed washers (nut side) on my EX-2. Don't know when CC's changed their drawings. I'll be down there today and probably remove a nut/washer and look at the thread available. Obviously there are enough threads as I installed washers/cotter pins. More interested in the grip length of the bolts.
I did notice that I installed washers (nut side) on my EX-2. Don't know when CC's changed their drawings. I'll be down there today and probably remove a nut/washer and look at the thread available. Obviously there are enough threads as I installed washers/cotter pins. More interested in the grip length of the bolts.
Hardware solutions for items “no longer available” still exist. One door closes another opens. My aviation career/experience
is a fair amount lighter on the GA and Supercub side than it is on the Transport category and old piston driven aircraft side but one constant applies….you have to hold these machines together with something and a lot of the same hardware applies. There are “surprises” that are available that a fair number of folks may not know about so I’ll toss a couple your way for what it’s worth.
Quick background example: Sometime after Douglas Aircraft built the DC-6, which, if you peruse the parts book you see they have listed proprietary, high tensile, ground to tolerance, close tolerance bolts each with a Douglas P/N.
They realized after some time all that was obsolete etc so they produced, published, and made available to operators their
“Manufacturers Approved” hardware substitution manual. It’s two volumes about 2 1/2” thick each.
When it comes to this stuff, and I instruct our new mechanics on this A LOT, just think “Equal to or better than” with virtually any hardware you use on anything. Obviously a little homework is needed but there are plenty of solutions for many variable hardware issues. Attached you will find a page from one of my go-to sources from Genuine Aircraft Hardware.
Their website is a treasure trove of good stuff and a hard copy of their catalog is a bench top must in my opinion.
See the highlighted line for a workaround to hogged out holes, installing bushings, etc.
Notice, as someone mentioned earlier in this thread, that NAS 13XX and 11XX series bolts were replaced by NAS 66XX and 62XX series. All true but there is still plenty of the 1300 and 1100 stuff out there for purchase if it comes to that. Other than the redesignated numbers, there are no differences between these bolts.
The oversized bolt codes as shown in the highlighted line are truly a great way to get past some issues. We use them in plenty of structural repairs when needed to get our hole tolerances back where they need to be. Also, for those familiar with Hi-loc fasteners, they are available in multiple oversized as well.
One last thing….The 1100/6200 series bolts are SHEAR application only. They have very short threads for use with shear height nuts. They are a great solution for these strut bolts BECAUSE the threads are so short, thus eliminating some or all of the issues that Steve mentions above about inverted bolts or removing landing rear. Available drilled (D suffix, doesn’t mean they’re aluminum in this case) or undrilled.
Well, one more. DO NOT ORDER THESE BOLTS USING WHAT YOU THINK IS THE CORRECT DASH NUMBER. They are NOT the same as AN hardware. If you do, your lengths will be all wrong.
Hope this makes sense, and maybe a solution to a problem or two.
Regards, Oz
Sorry, tried twice to clean up this photo so the chart is easier to read.
is a fair amount lighter on the GA and Supercub side than it is on the Transport category and old piston driven aircraft side but one constant applies….you have to hold these machines together with something and a lot of the same hardware applies. There are “surprises” that are available that a fair number of folks may not know about so I’ll toss a couple your way for what it’s worth.
Quick background example: Sometime after Douglas Aircraft built the DC-6, which, if you peruse the parts book you see they have listed proprietary, high tensile, ground to tolerance, close tolerance bolts each with a Douglas P/N.
They realized after some time all that was obsolete etc so they produced, published, and made available to operators their
“Manufacturers Approved” hardware substitution manual. It’s two volumes about 2 1/2” thick each.
When it comes to this stuff, and I instruct our new mechanics on this A LOT, just think “Equal to or better than” with virtually any hardware you use on anything. Obviously a little homework is needed but there are plenty of solutions for many variable hardware issues. Attached you will find a page from one of my go-to sources from Genuine Aircraft Hardware.
Their website is a treasure trove of good stuff and a hard copy of their catalog is a bench top must in my opinion.
See the highlighted line for a workaround to hogged out holes, installing bushings, etc.
Notice, as someone mentioned earlier in this thread, that NAS 13XX and 11XX series bolts were replaced by NAS 66XX and 62XX series. All true but there is still plenty of the 1300 and 1100 stuff out there for purchase if it comes to that. Other than the redesignated numbers, there are no differences between these bolts.
The oversized bolt codes as shown in the highlighted line are truly a great way to get past some issues. We use them in plenty of structural repairs when needed to get our hole tolerances back where they need to be. Also, for those familiar with Hi-loc fasteners, they are available in multiple oversized as well.
One last thing….The 1100/6200 series bolts are SHEAR application only. They have very short threads for use with shear height nuts. They are a great solution for these strut bolts BECAUSE the threads are so short, thus eliminating some or all of the issues that Steve mentions above about inverted bolts or removing landing rear. Available drilled (D suffix, doesn’t mean they’re aluminum in this case) or undrilled.
Well, one more. DO NOT ORDER THESE BOLTS USING WHAT YOU THINK IS THE CORRECT DASH NUMBER. They are NOT the same as AN hardware. If you do, your lengths will be all wrong.
Hope this makes sense, and maybe a solution to a problem or two.
Regards, Oz
Sorry, tried twice to clean up this photo so the chart is easier to read.
Attachments
Last edited:
