Stainless bolts on trailer coupler?

[flconrad]

I needed to replace my 2" coupler. The old one was bent. It is only held on by 2 bolts to the frame of the trailer and they were rusted. Bought 2 new stainless bolts and lock nuts to replace them. Friend of mine said do not ever use stainless fasteners because they will snap because they are soft. I have not heard of this, but listened to him and used new galvinized ones. I was afraid to unexpectedly lose my 21' cuddy cabin. Any one else know about this "don't use stainless on a trailer" warning?

 

[Mark42]

Re: Stainless bolts on trailer coupler?

Stainless is not soft, its hard and can be brittle depending on the grade. The stainless you buy in the hardware store is usually grade 5 and should be fine. Check for the grade mark on the head.

 

[Speedwagon]

Re: Stainless bolts on trailer coupler?

For a few bucks, you can probably have the coupler welded onto the trailer, and not have to worry. Any exhaust/muffler shop around will have a welder, and it's a quick job. Then the whole thing can be painted if you like, and you shouldn't see any rust.

 

[BoatBuoy]

Re: Stainless bolts on trailer coupler?

From boltdepot.com:<br /><br />"Stainless steel is an alloy of low carbon steel and chromium for enhanced corrosion characteristics. Stainless steel is highly corrosion resistant for the price and because the anti-corrosive properties are inherent to the metal, it will not loose this resistance if scratched during installation or use.<br /><br />It is a common misconception that stainless steel is stronger than regular steel. In fact, due to the low carbon content, stainless steel can not be hardened. Therefore when compared with regular steel it is slightly stronger than an un-hardened (grade 2) steel fastener but significantly weaker than hardened steel fasteners."<br /><br />I dis-assembled my trailer last summer and restored. All the bolts, screws, nuts, washers, etc. on it now are stainless, but the original coupler is welded.

 

[Mark42]

Re: Stainless bolts on trailer coupler?

From totallystainless.net<br /><br />"Stainless is a series of alloy steels which contain at least 12% chromium. Such steels will not rust when exposed to weather. The most common stainless steel is 304 which is an 18-8 alloy containing at least 18% chromium and 8% nickel. 304 is a non magnetic steel. The metric designation for 304 is A-2. Even more corrosion resistant alloys, such as 316, are available for some of our product line and are a good choice for high corrosion environments such as marine use. We carry medium strength hex and socket head cap screws made from strain hardened 316 in metric sizes. These fasteners have a strength designation of 80 and are approximately equivalent to metric 8.8 or a US grade 5. We have an extensive line of high strength stainless as strong or stronger than US grade 8 . The high strength bolts are made from age or precipitation hardened stainless and have a polished finish." <br /><br />Yes, stainless hardware is available in different harness ratings. Even the most common 304 stainless is much harder than common steel hardware without any grade marking.

 

[bigbad4cyl]

Re: Stainless bolts on trailer coupler?

i drive a semi for a living ,,,i crawl around in dirt with it allot....i pop frame bolts at frame junctures with stress all the time because the mechanic used grade 5 bolts there ,,,,,go save yourself some heartache and get some specialty tougher bolts ......or better yet go to a very very good welder , i snap frame welds all the time also that are inferior......i can tell the difference between a good welder and a poor welder in how long his welds last on my 5th wheel...i don't think the weight of a 21 foot cuddy weighing no more than 4,500 lbs would be to much on a grade 5 stainless bolt though ..........they do make stainless welding wire also in 304,316,318L etc.....................usualy when my bolts break the top cap pops off them....i think stainless is week in there threads , i heard they will strip eaisly because they are soft ,,,,im sure there sear strength is what got them there grade 5 rating....so a fine thread stainless would have more holding power in the threads when cranking down on it...

 

[Bondo]

Re: Stainless bolts on trailer coupler?

I think you fella's are going just a bit Over-Board.............<br /><br />2, 1/2" gr2 bolts will have a Tensile Strenght of Over 150,000lbs.......(common hardware store bolts)<br /><br />2, 1/2" gr5s will be at 240,000lbs........<br /><br />2, gr8s are Over 300,000lbs..........<br /><br />No Way I'd Ever Weld the coupler to the neape,......<br />After you Trash that new coupler,... You'll need to Shorten, or Replace the neape to attach the Next Coupler you'll need...............<br /><br />Oh,...Mark,.......<br />Even though there are Hard SSteel bolts available,......<br />The Common hardware store SSteel bolts are Very Soft..............<br /><br />Gr5 Or gr8 bolts are More than sufficient to attach a coupler to the neape.........<br />SSteel is Unnessessary,+ Not all that Desirable............

 

[dingbat]

Re: Stainless bolts on trailer coupler?

Stainless is used for specific applications and a boat trailer is not one of them. The only thing you’re guaranteed when using SS hardware is that you'll be using a hack saw to remove them. Use a galvanized grade 5 bolt and forget about it.

 

[bigbad4cyl]

Re: Stainless bolts on trailer coupler?

my trailer has all stainlesss hardware with anti seize compound applied to all the joints and it looks very sweet painted in blue perfection,with poly rollers.....i think the galvanized bolts would go good with a galvanized trailer cosmeticly...

 

[BoatBuoy]

Re: Stainless bolts on trailer coupler?

Originally posted by dingbat:<br /> Stainless is used for specific applications and a boat trailer is not one of them. The only thing you’re guaranteed when using SS hardware is that you'll be using a hack saw to remove them.

You've aroused my curiosity. Why would you need a hack saw to remove them?

 

[flconrad]

Re: Stainless bolts on trailer coupler?

Thanks to All for the great info. I learned a lot. I guess my friend was right.

 

[Reel Poor]

Re: Stainless bolts on trailer coupler?

I have an aluminum tripple axle 15,000 GVW<br />Performance Trailer and ALL the fasteners are Stainless Steel except the coupler bolts,they are galvanized. The coupler, and the tounge are also galvanized.

 

[dingbat]

Re: Stainless bolts on trailer coupler?

You've aroused my curiosity. Why would you need a hack saw to remove them?

SS by its alloying is a thermally active material meaning that is expands and contracts with even the smallest changes in temperature. What this means is when you put two pieces of the material together (ie nut and bolt) of different masses or alloys they will expand or contract at different rates. In a nut and bolt connection this usually results in the seizure of the nut to the bolt. The problem is further compounded by the fact that SS is a soft material and the threads have a tendency to distort or “gull" as it's called without lubrication between the mating parts, Anti-seize is typically used to minimize this effect but the probably of the materials gulling is still not in your favor.<br />I work in an industry where Stainless materials are a necessary evil and I don’t use SS hardware for anything unless it’s an absolute necessity. <br /><br />BTW You can’t cut SS with a cutting torch either, thus the hack saw comment.

 

[Wotknot]

Re: Stainless bolts on trailer coupler?

BTW You can’t cut SS with a cutting torch either, thus the hack saw comment.

But you can with a plasma cutter<br /><br /><br /><<<<drumming up business.....

 

[umblecumbuz]

Re: Stainless bolts on trailer coupler?

The main reason that stainless nuts seem to bind on their stainless bolts is because the threads on the bolts are molded and the internal threads on the nuts are cut.<br /><br />The nut threads are rougher, and when overtightened - which we all seem to do - they deform and bind, sometimes causing localised 'cold welding', making later disassembly difficult and often stripping or damaging the thread. The cure, and it is usually a total cure, is to use proper antiseize when assembling.<br /><br />If this is done, there will not be any need for hacksaws, plasma cutters or the like.

 

[tommays]

Re: Stainless bolts on trailer coupler?

all bolts are made the same way they wack the crap out it on the head on a header machine and they form the threads in the thread rolling section<br /><br />other than something special that might be single pointed on a screw machine or lathe<br /><br /><br />tommays<br />

<br />

 

[dingbat]

Re: Stainless bolts on trailer coupler?

The cure, and it is usually a total cure, is to use proper antiseize when assembling.<br />

Don't kid yourself, anti-seize is 30% effective at best even under normal conditions. <br /><br />It doesn’t matter how the threads are formed you still have to end up within the confines of the particular tolerance class. A Unified standard series 2A nut and bolt shall confirm to the dimensional specifications of this standard no matter how the threads are formed. If they met specification there should be no reason for the parts to have issues mating to each other. <br /><br />When all is said and done it all comes down to the temperature instability of stainless steel that is the problem. In critical applications we’ve gone as far as to design and make our own stainless hardware with tolerances appropriate for the conditions. 304 stainless steel is about 25% more reactive to a temperature change than that of mild steel.<br /><br /> thermal expansion

 

[tommays]

Re: Stainless bolts on trailer coupler?

i my work we can only use stainless and dont seam to have these problems with 18-8 ,304 or 316 bolts<br /><br />now if you run the bolt on with and inpact gun you might creat a problem<br /><br /><br />but all are nuts expect nylock spin on finger tight with no binding<br /><br /><br />tommays

 

[umblecumbuz]

Re: Stainless bolts on trailer coupler?

Getting a bit too tech for me, but here are a few more thoughts about using stainless nuts and bolts:<br /><br />First, don't use power tools. The faster the speed of running a nut up a bolt, the greater the chance of stainless galling. Tighten evenly and slowly.<br /><br />Second, and more importantly, always lubricate with an antiseize. There are many antiseize products for different applications. Plain wax is a good antiseize, although almost any wax will work.<br /><br />Third, do not overtighten. If you are working with torque figures for other steels, reduce these by at least 20% if possible when using stainless.<br /><br />Threaded fasteners that are made from Stainless Steel or other alloys which self-generate an oxide surface film are all prone to galling. Stainless easily gets a work-hardened surface. When the surfaces are rubbed together under stress (like tightening a nut on a bolt) they harden, then bits of the harder metal break off. The surface roughness increases, and this results in galling - localised 'cold welding'.<br /><br />One of the industry's acknowledged experts on the subject is a guy called Joe Greenslade. His website has articles on this subject:<br /> http://www.greensladeandcompany.com/

 

[dingbat]

Re: Stainless bolts on trailer coupler?

Where talking the same thing, different language. <br /><br />You talking means and I’m talking cause. Either way you end up with the same results. <br /><br />Stainless is a bear to work and should only be used when absolutely necessary. These guys changing all their boat trailer hardware over to stainless for appearance are in for a rude awakening sooner than later. Throw dissimilar metals into the equation and you really have a fine mess.