Bolts?

I used these, added a 3/8 washer. Did not paint, I figured the bolt head is up above the floor and the paint will be wore off as people move around in the Jeep. Got the longer ones and cut off to what I needed.

3/8"-16 x 3" ASTM F879 Hex Drive Grade 316 Stainless Steel Button Socket Cap Screw | Fastenal

 

I use, and like, 3/8-16 serrated flange bolts and nuts, zinc finish, likely because I had access to huge quantities. No need for flat washers or lock washers. After several months the zinc is ripe for painting. But I will admit that I used 7/16 NF carriage bolts when I reworked the rear bed mounts. I like the round head in the bed for obvious reasons. Honestly can't remember (as with lots of things) why 7/16" diameter, but no doubt there was a good reason.

 

Use of Washers and Flange Heads | Archetype Joint

Think also about what grade to use? Grade 5 or Grade 8?

 

If I recall correctly I filed the hole square.

 

Impact will zip them down. Probably won't ever take it back off right?

 

I have done this several times. You end up using 1/2" bolts and the floor is so thin that it still doesn't hold when you go to remove it. I have been able to remove them very easily by welding a nut onto the top of the carriage bolt though.

 

Grade 5 is almost overkill for body bolts. Grade 8 is certianly unneeded.
-Donny

 

Why is it stupid? Im asking for a friend.

 

That is the reason for filing the hole square so that the bolt has something to grab on. Under the dome of a carriage bolt hides a square.

 

Oh I thought you were saying it's a stupid idea to weld a nut to the frame to put the bolts through. I did not understand the carriage bolts and the welded nuts part

 

IIRC my Jeeps have had plain hex bolts with fender washers through the floor, everywhere the bolt head contacts the steel floor. Some locations go through the heavier gauge channels, and have ordinary flat washers. Not sure why you need anything fancier than this. It may be different for a M38A1 tub though.

 

I prefer to use 5/16 and 3/8" carriage bolts.
Basic grade 2 allows you to break them off after they have rusted and seized through the years.