Broken S/O

[Montana_4397]

Charlie, Stainless bolts, as a rule , eo do have as high a shear strength as carbon steel. Any hardware store should be able to supply the grade 8 bolts. They are designated by the number of radiating lines on the head. Again the store will show you the difference.

Best Regards, Ted

[Montana_4397]

Charlie, Stainless bolts, as a rule , eo do have as high a shear strength as carbon steel. Any hardware store should be able to supply the grade 8 bolts. They are designated by the number of radiating lines on the head. Again the store will show you the difference.

Best Regards, Ted

[Illini Trekker]

Charlie Grade 8 bolt is about as soft as a bolt gets, as far as grade.

Dale posted earlier this about an upgraded use of bolts
mobilrvn,

That bolt needs to be a 1/4-20X2" grade 8 hex head bolt. It uses a nylok 1/4-20 hex nut. If possible, purchase zinc plated ones to protect against rust and corrosion. In fact, purchase several and keep them as spares. You can purchase these any where. Lowes, Menards, Home Depot or any hardware store.

Any of you folks that where at the Reno Rally probably got some of those as I had them there for hand-outs.

The reason those are grade 8 is because, these are designed to be weak points. They shear before something more expensive and time consuming to repair is damaged.

If you have any further questions or need help, feel free to call me at the number shown above or call our toll free number, 866-524-7821. My extension is 4542.

I'd think the stainless could cause failure some place else!

[Charlie]

Thanks Dennis, that makes sense, I was thinking that if bolt failure was to occur why not prevent that by using stainless, but I see Dale's point. I must have missed this post somehow but will pick up some spares next trip to Lowes's.

[sreigle]

Charlie, I bought some in Carson City, NV. Lowe's had them but Home Depot did not. So if one place doesn't, try another.

[Charlie]

Steve-
Picked up the bolts at a local auto parts house today. Cheap insurance.

[Wrenchtraveller]

Just to clear up some misinformation on Bolt grades

Grade 2 bolt- no markings made of steel tensile stength of 74000 PSI yield stength of 57000 PSI
Grade 5 bolt- 3 slashes on head , steel, tensile stength of 120000 PSI yield stength of 92000 PSI
Grade 8 bolt- 6 slashes on head , Alloy Steel tensile strength 150000 PSI, yield strength 130000
316 stainless gives you only a tensile strength of 100000 PSI and a yield strength of 65000 PSI

As you can see a Grade 8 bolt is one of the stronger, harder bolts you can use and normally would not be used a a shear pin.

As the gentleman from Lippert had pointed out , the reason these bolts were failing is because they had used a shorter bolt which allowed the threaded portion to come under stress.This weakens a bolt quite a bit.

Any mechanical device will break the weakest link and the slide out rooms are doing this.
If your slide out starts breaking these Grade 8 bolts after you replace them with the longer ones, you probably have another problem.

Metric bolts use a different marking system and that information as well as the information I have posted is very easy to find on the net. As a Millwright , the most common Grade I use is Grade 5 but for high strength applications we use Grade 8 and when I put my 5th wheel hitch on 6 weeks ago, I was happy to see it came with Grade 8 bolts.

This post is not to point out error, simply to educate, Thanks, Wrenchtraveller.

[Northstar]

Thanks guys for the great info. I will be picking up some of these bolts for spares.

[richfaa]

Thought I had better go out and buy some of those bolts as described and throw them in the Camper tool box,Got 4 of them at our local hardware store (yes we have a real hardware store here in town) 4 of them for 1.83 tax included. Cheap insurance.

[Trailer Trash 2]

Well I hate to POP Bubbles on screww types, Stainless verses Grade 8, all of you that think stainless has a stronger shear than grade 8 are wrong, Stainless is the weaker of the two Titanium is stronger than stainless but not as strong as Grade 8. I will get the rockwells for them if requested. I have used Stainless and Titanium in a lot of automotive projects, and they do not rust. you do not see stainless bolts holding a cylinder head together, even though it would be nice because you wouldn't need anti seiz on the threds and they dont rust.

Stick with the grade 8 bolts you will be better off with them

[HamRad]

Hi Don,
I think the info Wrenchtraveller posted agrees with what you are saying about stainless. At least that is what I got from his posting.

If I remember correctly Dale indicated at Reno that the main problem was not the bolt type or rating but rather that they were too short. So whatever rated bolt they had in there to begin with was probably correct but just too short. With the longer bolt folks should not have the problem.

Don't know why I'm posting on this issue since I do NOT even have this type slide!

Good luck.

HamRad

[Trailer Trash 2]

Yep I saw that after you mentioned it Dennis. I did not read them all shame on me.
The big problem is the shearing action simular to those screw cutters that are on electricans crimping tools, that is the same thing that is happining to these screws. I often wonder if using a softer screw instead of the # 8 would be better , as far as wear on the square toubing and the drive shaft so they dont get egged, I guess it would be easier to change a bolt every now and then apposed to the shaft and driver. I guess it will be the decision of the indvigual.

TT2