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07-12-2019, 09:01 PM
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#1
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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Possible problem with Elevator bolts
I'm involved with rebuilding a 92 Excella. I did a shell off and I'm now preparing to install new channel to the frame. I decided to use 3" stainless steel hex head tap bolts with stainless flat washers and stainless nylon centered lock nuts. I've decided to dry fit the new channel and make sure the shell will fit over it okay before I cut and install the flooring. I installed the first tap bolt then I broke the second bolt during installation. Now, I'm wondering if stainless steel is a good idea since it is rather soft. I'd love some advice and or encouragement. I'm happy to buy new bolts, washers and nuts if that's what is needed, I just want this to be right.
Also, has anyone else used lock nuts for this purpose and is installing and removing them okay or does that make them less effective?
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-12-2019, 09:18 PM
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#2
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Rivet Master
2007 30' Classic
Oswego
, Illinois
Join Date: Jul 2010
Posts: 13,655
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Yes, stainless is soft. You could always use nylon or stainless washers with steel bolts. I have done that on various projects to reduce galvanic interference where touching aluminum. I dont see an issue with nyloc nuts.
__________________
-Rich-
"If the women don't find you handsome, they should at least find you handy." - Red Green
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07-12-2019, 09:36 PM
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#3
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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Quote:
Originally Posted by dznf0g
Yes, stainless is soft. You could always use nylon or stainless washers with steel bolts. I have done that on various projects to reduce galvanic interference where touching aluminum. I dont see an issue with nyloc nuts.
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Good thought. Stainless bolts were not my first choice, but then I may have over thought it, remembering how rusty most of 26 years old elevator bolts were. Then I thought about all of the stainless screws and bolts that are used on sailboats and the like and they get a lot of stress and I decided to give stainless a try. When the second bolt broke from twisting on that nylock nut it made me question how well these bolts would hold up bouncing down the road. The thought of them shearing in half scares me. Even rusty the original ones were still in one piece.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-13-2019, 07:00 AM
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#4
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Rivet Master
1973 21' Globetrotter
Houston
, Texas
Join Date: Sep 2009
Posts: 3,314
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Believe it or not, the galvanic interaction between stainless and aluminum is many times higher than it is with regular steel.
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07-13-2019, 07:12 AM
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#5
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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I did not know that.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-13-2019, 08:05 AM
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#6
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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As may be apparent I don't know much of anything about steel. Here I am ready to begin bolting down my channel and I discover that I bought the wrong type of steel bolts.
In my case these bolts are fastening the channel to the outriggers and frame perimeter. Instead of using the round wafer headed elevator bolts I'm using hex head full thread bolts unless I find some partial thread bolts that will do the trick. Since I'm using nylon insert lock nuts I'm thinking that bending over the remaining bolt stem is not necessary and if that is true then neither do they need to be 3" long. How does that jive with conventional wisdom?
Are Grade 8 bolts acceptable?
If not what type of steel is recommended?
Regardless of the bolts I end up using is it wise to use the Stainless flat washers and Stainless Nylock Nuts I already have?
I'm open and ready to receive your shares.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-13-2019, 09:28 AM
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#7
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4 Rivet Member
1968 26' Overlander
CORDOVA
, TN
Join Date: Apr 2018
Posts: 414
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I like the idea of using stainless bolts, although, you still have a steel frame, and there can still be rust....Unlike the boat you referenced, where virtually no steel is found at all.....
Perhaps there is a higher grade of stainless bolt available at your source?
...in either case, I like your idea, even if you cannot make it work. Seems odd that threading a nut onto those bolts is stressing them out that much.
__________________
1968 Overlander Land Yacht International
Ford E-350 W V-10 booom!
2018 Chevy Tahoe smooooooth
Find a way to enjoy life and have fun, every day !
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07-13-2019, 09:38 AM
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#8
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Rivet Master
1964 26' Overlander
1974 31' Sovereign
Milton
, ON
Join Date: Oct 2002
Posts: 1,223
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I use stainless steel bolts whenever possible in camper renovations. Occasionally I've had problems with galling that has resulted in broken bolts. This may be the problem you're facing. I don't think the difference in the strength of a bolt (SS vs various grades of steel bolts) is going to matter in attaching the shell to the frame.
There is information on Thread Galling here.
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07-13-2019, 09:56 AM
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#9
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New Member
2015 22' FB Sport
LEWISTON
, NY
Join Date: Jul 2019
Posts: 2
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Quote:
Originally Posted by Re-Pete
I'm involved with rebuilding a 92 Excella. I did a shell off and I'm now preparing to install new channel to the frame. I decided to use 3" stainless steel hex head tap bolts with stainless flat washers and stainless nylon centered lock nuts. I've decided to dry fit the new channel and make sure the shell will fit over it okay before I cut and install the flooring. I installed the first tap bolt then I broke the second bolt during installation. Now, I'm wondering if stainless steel is a good idea since it is rather soft. I'd love some advice and or encouragement. I'm happy to buy new bolts, washers and nuts if that's what is needed, I just want this to be right.
Also, has anyone else used lock nuts for this purpose and is installing and removing them okay or does that make them less effective?
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I do not claim to understand anything about the various qualities of stell and bolts. When I have bolt problems I visit a Fastenal store and get excellent advice for the most exotic solutions in SAE DIN ISO standards - just as I need it per case to be solved.
I am not getting paid for referencing them but I can tell you that they were always helpful!
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07-13-2019, 10:59 AM
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#10
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Stainless is brittle and the threads gall easy. Always use anti-seize, and you can buy higher quality stainless fasteners than those typically available at big box stores.
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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07-13-2019, 12:25 PM
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#11
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3 Rivet Member
2019 27' Tommy Bahama
Midland
, MI
Join Date: May 2019
Posts: 109
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Stainless Steel
Stainless Steels comes in many varieties - it's basically a generic term for 5 classified types that are defined by the basic metal recipe (content). The recipe is the percentage of chromium. nickel, sulfur, iron, and many more elements, as well as the metallic structure itself. These types are then further classified into hundreds of different grades. These have been developed over many years to satisfy different requirements - corrosion resistance, strength, weldability, formability, etc. Consequently it's not wise to base a design decision solely on the term, Stainless Steel. Many stainless steel grades are soft, and in fact are often quite weak compared to steel. Most stainless grades do not harden well, as steel does, and this leads to many other issues compared to steel. Galvanic reaction also varies based on type. The most common stainless grade fastener normally available at hardware stores is type 18-8 - a low cost, weak and soft grade. It has decent corrosion resistance, but is much poorer than another semi common grade, 316. A 316 bolt will cost 3 times what the same size 18-8 bolt does.
If I were doing the job you are, I would see about exchanging the stainless steel fasteners for good old grade 5 steel bolts, nuts and washers. These will do the trick strength wise and last for a long time. (Grade 5 bolts have 3 radial lines on the head.) I wouldn't use the more common and cheaper grade 2 bolts - these have 35% less strength of a grade 5 bolt. Tensile yield strength of 57,000 psi vs. 92,000 psi. I think grade 8 is overkill but better yet if you want to pay for it. For comparison Stainless 18-8 bolts yield strength is 20,000 to 65,000 depending on exact composition.
Precoating the parts prior to assembly, and then recoating after assembly with a good primer and paint will help as well. Not sure if this helps, but I guess my bottom line suggestion is to do some fastener research or talk to a true professional before you embark on a very difficult project.
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07-13-2019, 12:51 PM
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#12
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Rivet Master
2019 27' International
2014 25' International
2006 23' Safari SE
Boulder City
, Nevada
Join Date: Aug 2007
Posts: 5,703
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For an outside the Airstream advice, check with Shelby Cobra (Carroll Shelby origin). They have Aluminum shells on their frames. I am sure they would be happy to tell you what kind of hardware they use. There are all kinds of hardened steel bolts used from boats to airplanes.
Shelby American, Inc. Las Vegas, Nevada (Great tour as well!)
aka: Carroll Shelby Museum and Factory Tours in Las Vegas
I like the polished aluminum... maybe, some day.
__________________
Human Bean
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07-13-2019, 01:56 PM
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#13
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3 Rivet Member
2018 27' Flying Cloud
INDIAN HARBOUR BEACH
, Florida
Join Date: Jul 2018
Posts: 245
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What Can I Do to Prevent Galling?
Slow Down Installation Speed
Because heat generated by friction is a contributing factor in galling, slowing down the installation speed can prevent galling. It is recommended that power tools not be used for the installation of stainless steel or other fasteners prone to galling. This is especially important when using nylon insert lock nuts as these nuts significantly increase the chance of galling.
https://www.boltdepot.com/fastener-i...d-galling.aspx
THX for the discussion and learning!
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07-13-2019, 10:00 PM
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#14
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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Quote:
Originally Posted by DavidsonOverlander
I use stainless steel bolts whenever possible in camper renovations. Occasionally I've had problems with galling that has resulted in broken bolts. This may be the problem you're facing. I don't think the difference in the strength of a bolt (SS vs various grades of steel bolts) is going to matter in attaching the shell to the frame.
There is information on Thread Galling here.
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Grant, Sincere thanks! Damn! That Galling information was very enlightening! I know I've heard of galling before, but I had a complete misconception of what it was. This article particularly dwells on Stainless steel bolts and nylon insert lock nuts. I was installing the lock nuts with an 18V Milwaukee Fuel impact driver. I never considered the friction and heat that was generating. Respect!
Everyone who does not no what galling is or how it happens should read Grants link to the Galling article at the BoltDepot.com.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-13-2019, 10:15 PM
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#15
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Rivet Master
2022 20' Basecamp
1968 17' Caravel
Los Osos
, California
Join Date: Nov 2013
Posts: 613
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Great info. Thanks
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07-13-2019, 11:03 PM
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#16
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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I highly recommend to anyone who like me is unsure of exactly what galling is and how it's caused to read Grants link to the Galling article at the BoltDepot.com.
For those deep divers like myself I also recommend the following article on the albanycountyfasteners.com site on the problems of using stainless steel and aluminum together.
And thanks to everyone who has shared thus far, it's been truly appreciated and studied.
Because I can only find the stainless bolts I wish to use in 18-8, I'm going to either use grade 5 or grade 8 bolts to bolt down my channel and I think I'll follow albanycountyfasteners.com advice and use these washers to protect the aluminum.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-15-2019, 09:21 AM
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#17
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New Member
1994 34' Limited
Charlotte
, Michigan
Join Date: Dec 2012
Posts: 1
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Looks like to me that your problem is, trying to use self tapping stainless bolts in steel. Drill hole and use a nut on the back side if you can get to it.
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07-15-2019, 11:41 AM
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#18
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4 Rivet Member
1972 25' Tradewind
Calgary
, Alberta
Join Date: Jul 2015
Posts: 297
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Just pre-drill your hole a bit smaller than the tap screw/bolt you're using, still have it tab but not doing all the heavy drilling.
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07-15-2019, 12:09 PM
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#19
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Rivet Master
1992 29' Excella
Virginia Beach
, Virginia
Join Date: Jul 2012
Posts: 747
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Quote:
Originally Posted by Jeff Sage
Looks like to me that your problem is, trying to use self tapping stainless bolts in steel. Drill hole and use a nut on the back side if you can get to it.
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Quote:
Originally Posted by Monza
Just pre-drill your hole a bit smaller than the tap screw/bolt you're using, still have it tab but not doing all the heavy drilling.
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These are just 1/4" bolts placed through 1/4" holes drilled through the channel and outrigger or cross member with a 1/4" drill bit. They require a nut to secure the bolt. And I guess a nut to be doing all of this in the first place.
__________________
Pete
Virginia Beach, VA
1992 29' Excella Classic
TV 2006 Dodge Ram 2500
Mega Cab Diesel 4x4
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07-15-2019, 04:30 PM
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#20
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Rivet Master
1973 27' Overlander
Currently Looking...
Jupiter
, Florida
Join Date: Apr 2006
Posts: 2,060
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After twisting off a few SS bolts once I dropped the shell I automatically bumped up one size (5/16 to 3/8", 1/4 to 5/16" etc.) when installing stainless bolts & screws - the big-box store stainless bolts don't make Grade 3, internet mail-order can supply proper 'head stamped' bolts but there is still a high likelihood of QA (quality assurance) issues with bulk fasteners out of China.
The one thing I had problems sourcing was stiff enough stainless washers to keep from dimpling aluminum C-Channel and plywood from merely tightening the fasteners.
My solution was to use an oversize SS fender washer backed up with a large phosphor-bronze or Gr8 steel washer under each nyloc nut.
__________________
The days are short and the night is long and the stars go tumbling by.. . ~Airstream~
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