The Stovebolt Site Forums The Shop Area Engine Shop Question about which bolts I should use on my chassis

I have a 1968 c-10 which is stripped down to the frame and been sand blasted. My question is what strength bolt should I use to reattach my crossmember that is under the engine? I also have to attach the first and last crossmembers, still looking for the last one if anyone has one for good price, to the chassis as well. They looked like someone tried to fight a stump and lost so I removed them. I have #5 strengh bolts and I have been told it would be okay by a knowledgeable person, but just wanted to get yall's opinion.

Thanks,
Jarrid

For the crossmember list it in the parts wanted of the swap meet. (if you haven't already) If the crossmembers are resting on/inside the chassis rail I think #5 would be fine. I would recommend #8's if it has anything to do with suspension although #5's have been used for ages. If I remember right yours is a half ton and you will not be "carrying heavy loads" or fighting stumps

Grade 5 should be fine for crossmembers, suspension parts should use grade 8. But, remember the crossmembers were attached with rivets, and thy were not heat treated. Just soft steel. They did have the benefit of filling the holes so there was not any clearence for movement.

I, myself refuse to use anything other than grade eight bolts. I`ll pay the extra. 2cents worth.

I agree, I use grade eight. I have been replacing a lot of hardware on my truck and I have been replacing it with stainless steel. I know the when I walk into Wally's Hardware they are glad to see me. It cost more but some of those nuts,bolts and screws may not be seen for another 70 years.

Grade 5 for a shear load and grade 8 for a tincile load. Yes it is true a grade 8 is stonger than a grade 5 but they are also more britle. I learned this from a fence posthole awger. I was using grade 8's for the shaft pin and they would shear right away. An old former looked at one of my broken bolts and told me to use a grade 5 insted. Its softer and will flex where the grade 8 will snap. He was right the same grade 5 bolt is in there today hundreds of holes later.

Don't use stainless, they are not very strong as a general rule. OK for looks, but when you are really counting on it use grade 5 or 8.

I would use hot rivets. I replaced about 2 dozen missing or broken 3/8" rivets on my 2 ton frame. It's pretty simple with an air hammer, a torch, some homemade tools, and a friend.

For the parts of my frame that I modified and wanted to bolt in so I could remove them I went to a big truck parts store and bought special frame bolts, they are grade 8, black, have washer heads and washer type self locking nuts to match. They come in 3/8", and 1/2" diameter as well as larger and perhaps smaller, that's just the sizes I used. Some new tractor trailer frames are assembled with them, no rivets.

Rivets sound the best to me, if you are able to properly install them.

If you use stainless steel (or any kind of) bolts, make sure they are at least grade 5. Totally Stainless sells grade 5 and grade 8 stainless bolts.

Another thing to watch out for. The other day I went to Ace Hardware to buy some bolts. They had plenty of grade 5 bolts, but no grade 5 nuts. Make sure if you use grade 5 bolts that you also use grade 5 nuts.

Where do you get the rivets?

I did a search for info on nuts and came up with this site. It has some good information about nuts and bolts.

http://www.smithfast.com/products.htm

This should answer some questions.

Another good source for information and fasteners is the McMaster-Carr catalog.

McMaster-Carr

They show the strength, if available, for each cap screw or nut, for many materials and grades. A grade 8 3/8-16 cap screw is rated at 150,000 psi, a grade 5 at 120,000 psi, an inexpensive stainless (18-8) at 70,000 psi, and an expensive stainless (17-4PH) at 140,000 psi. The grade 5 costs 20 cents each and the 17-4PH costs $7.50 each. I have broken hardware store stainless steel cap screws by applying typical torque values.

Hoyt

Lonnie,

Our Ace Hardware in Missoula has Grade 5 bolts in bins but the Grade 5 nuts are in cardboard slider boxes which are perched on top the bins. Go figure.

I buy rivets from McMaster Carr, most of the time they have the size I need. Sometimes I buy long and cut them to length, and sometimes I go elsewhere to find odd sized ones.

Greg,

Thanks for the resorce on the rivets, I have one of their catalogs on my desk. I'll take a look tomorrow. I need to replace some rivets on my frame. I was going to use bolts, but like the idea of using rivets. It will take me back to my blacksmithing days.

Wally,

The Ace Hardware owner is a friend of mine; when I asked him about the nuts he said he can't please every customer. That was after I told him that stocking the grade 5 nuts would solve both needs. It's a small store, but he does have a good selection of grade 8 nuts and bolts.

Note that totallystainless.com has high-strength stainless suspension hardware that is even stronger than grade 8. And they will never rust!

a lot really depends on the individual stores and location, I think!! I usually have real good luck at the Ace Hardware but today I walked into one I hadn't visited in a while. The guy greeted me at the door and when I told him I wanted two studs that were standard national coarse threaded he shook his head and said we only have METRIC. I hate to do it but a lot of times I drive the 19 miles to my hometown to McCraw's Hardware. The guy who runs it went to high school with me and he is carrying on the store his daddy ran for years. Talk about bolt bins and lots of odd stuff we look for he has a lot of it. Sometimes my luck is good!!!

You Guys are fantastic. This site is Fantastic. This is more info than I would have ever thought I would get.

Thanks to all,
Jarrid