Welding Grade 8 Bolts

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So I am almost done with my jeep bumper that I decided to revisit finally.Anyway, I was assuming it is in my best interest to mount it to the frame with grade 8 bolts. (it has shackles on it)Problem is, in order to achieve this I have limited mounting options because the bolt holes are blocked when the bumper slides on. I am not looking to nuts making some open multi-piece bracket.So I wanted to weld a pair of grade 8 bolts to a backing plate that could be inserted in the frame tube before the bumper goes on and then secured.If I weld a pair of grade 8 bolts to a piece of 3/16" or 1/4" plate, will it eliminate the temper? Will more than likely be welded via mig unless there is a reason to TIG it.Heck are the grade 8 bolts even worth it?Here is what I am working with. The two mounting plates are 3/8" plate. (not sure if I went overboard on that?) The bumper itself is all 3/16" plate, the only part that will support any kind of load is the shackles and the plate they go through. My main screwup was not mounting the shackle plates directly against the mounting bracket, so I will need to bulk that up before I finish.Attachment 1060881Attachment 1060891Attachment 1060861Attachment 1060871Last edited by BrooklynBravest; 04-01-2015 at 11:59 AM.www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:I think you will be fine welding on the bolts
Reply:Hey man, I've got  better idea.Let me post some pics of the bront bumper I'm building for my truck...Just a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:Just a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:That's what I was thinking he should do to. He has the setup same as you AK. He could even just bolt the bumper on instead of weld nuts on. Time to sand blast that bumper AK and paint her pink lol jkLast edited by motolife313; 04-01-2015 at 02:07 PM.
Reply:Originally Posted by motolife313That's what I was thinking he should do to. He has the setup same as you AK. He could even just bolt the bumper on instead of weld nuts on. Time to sand blast that bumper AK and paint her pink lol jk
Reply:because the bolt holes are blocked when the bumper slides on
Reply:Just a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:Nice lookin' bumpers for both of you!! AK I'll suggest running a brace, either angle or sq. tube, from the one furthest back mounting bolt out to the middle of the outside corner. If you tap something solid very hard on that corner the channel will fold right at the mount bracket.                                      MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:The main issue is that cross member blocks the medial side of the frame rails, so a through-bolt is not possible.I think my best approach is to weld nuts to the plates I made, slides those inside the frame rails and bolt it from the lateral side. That also eliminates welding the nuts whatsoever.I would love to add a hitch to this thing as well but a factory hitch gets secured to that cross member, not really sure how I would pull that off. Probably better off making a cutout for an aftermarket hitch down the line.
Reply:This is what I used to mount my TJ bumper, but it was a fully enclosed bumper.  You use the stock angle brackets or make your own.http://www.atozfabrication.com/store...cat=275&page=1
Reply:Originally Posted by mla2ofusNice lookin' bumpers for both of you!! AK I'll suggest running a brace, either angle or sq. tube, from the one furthest back mounting bolt out to the middle of the outside corner. If you tap something solid very hard on that corner the channel will fold right at the mount bracket.                                      Mike
Reply:Picked up 3/16" 3" C-channel locally, paid $15 for 24" of it. Basically doing what you did but on the rear.My question now, is will a pair of 1/2" grade 8 bolts on either side hold this thing, or should I drill a third middle one on either side?Channel is actually a lot better. For starters its a lot easier to work with and It allows me to get the mounting point closer to the mounts for the shackles. If its within 1" of the shackle mount, is it worth beefing it up with a gusset from the channel to the face?Attachment 1062221Attachment 1062231Attachment 1062241Attachment 1062251www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:The holes in the frame look bigger then 1/2   I would look at getting  5/8 bolts  and just make a plate 1/8 or really big washers to cover the out side of the frame were the bolts go though.  So it put the loads on the upper and  lower part of the box frame.  The weak link will be pulling the bolts though the frame . If you winched it at a angle for some reason out of heavy mud. but i wouldn't worry much jeeps are lightLast edited by Bigrich954rr; 04-02-2015 at 03:56 PM.
Reply:Originally Posted by Bigrich954rrThe holes in the frame look bigger then 1/2   I would look at getting  5/8 bolts  and just make a plate 1/8 or really big washers to cover the out side of the frame were the bolts go though.  So it put the loads on the upper and  lower part of the box frame.
Reply:Ok  1/2 would be fine   cause 4 would put you close to 60 k shear loadLast edited by Bigrich954rr; 04-02-2015 at 04:02 PM.
Reply:Originally Posted by Bigrich954rrOk  1/2 would be fine   cause 4 would put you close to 60 k shear load
Reply:Dont bumpers need to give a little and have shock absorbers on them and/or tied into an air bag system in 20-30 year old vehicles?  I don't see how any of these can be street legal...
Reply:Originally Posted by rlitmanOn the bolts perhaps, but wouldn't the bolts just tear the frame well before that?  That's why I can't picture grade 8 in this use.
Reply:Originally Posted by Bigrich954rrYup would tear right though the frame which is why i would like to see a plate added to out side. but unless you burry a jeep deep deep in mud it will never take that much to pull it out
Reply:Originally Posted by BrooklynBravestAre you saying a plate on the outside just to sandwich the frame rail? That can be arranged no problem if you think its worth it.
Reply:Originally Posted by Bigrich954rryes just to sandwich the frame and spread the load over more area. only worth it if you plan to get it really stuck, for light mud not worth it
Reply:Originally Posted by BrooklynBravestAs far as the value of using grade-8 bolts here is there any reason not to? There really isn't any added expense. I was not going to use a grade-8 nut, since the load is lateral anyway.
Reply:Originally Posted by rlitmanActually, yes.  The grade of steel used is subject to hydrogen embrittlement, crevice corrosion cracking (why grade 8 bolts only come plated, but that's lost when you weld), and getting just generally brittle in the haz after welding.  I'd stick to grade 5, which isn't heat treatable, and doesn't have these issues.
Reply:Originally Posted by M J DI have used plenty of grade 8 bolts in black oxide finish. If you live in a road salt climate I would coat the channel and plates with rubberized undercoating and assemble it before it fully dries.Right, I was referring to the backup plates .
Reply:Real nice work on those bumpers!2 Hobart MIG welders, 1 on the gas 1 flux coreHTP Invertig 221 DV Eastwood TIG200HTP MIG 2400
Reply:Originally Posted by BrooklynBravestIf I weld a pair of grade 8 bolts to a piece of 3/16" or 1/4" plate, will it eliminate the temper? Will more than likely be welded via mig unless there is a reason to TIG it.
Reply:Originally Posted by MikeGyverA trick you can do is tack a 1/16" tig welding rod to the top of the bolt head then you can fish the bolt inside the frame and stick it out through the holes to get a nut on it.
Reply:Ok so I think I am on the right track now.Before i make my trip to home depot lets just verify.I should use grade-5 instead of grade 8.3 bolts per side sandwiching the frame between C channel and 3/16 plate.Only lightly tack the nuts to the channel.www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:Ok heres where I stand so far.Got the C channels all drilled out. Have to weld the nuts on cut the outside plate and drill the frame still.I ended buying grade 8 bolts. They didnt sell grade 5 in 1/2" and I don't feel like paying for shipping.Is there any reason to use a grade 8 nut with this or am I wasting $1 a nut by buying them? I don't see any way that the nut is receiving force other than tightening it down, all force should be directed at the shaft of the bolt.Attachment 1062951Attachment 1062961www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:Originally Posted by BrooklynBravestOk heres where I stand so far.Is there any reason to use a grade 8 nut with this or am I wasting $1 a nut by buying them? I don't see any way that the nut is receiving force other than tightening it down, all force should be directed at the shaft of the bolt.
Reply:Originally Posted by Gerry1964Bolts can act in two ways, namely in tension and shear. The individual parts of a bolt comprise a hexagonal head and a circular section shank, which may be fully or partly threaded. They come in shank diameters from very small (6mm) up to 36mm. Larger diameters may be available to special order.Two grades of bolt are commonly used. These are grade 4.6 and 8.8. The first digit relates to the ultimate strength of the material, whilst the second is the ratio of yield stress to ultimate strength. Thus grade 4.6 bolts have an ultimate material strength of 400N/mm2 and the yield (or proof) stress is 60% of the ultimate strength. Similarly grade 8.8 bolts have an ultimate strength of 800 N/mm2 and a ratio of yield/proof stress to ultimate strength of 80%. Simple grade 4.6 bolts without corrosion protection are commonly called 'black'bolts'Ideally you want to match the bolts to the nuts as using a lower grade nut will ultimately weaken the connection and makes buying the grade 8 bolts a waste of time
Reply:why would you want grade 5 over grade 8?Welding/Fab Pics: www.UtahWeld.com
Reply:Originally Posted by MikeGyverwhy would you want grade 5 over grade 8?
Reply:Originally Posted by Gerry1964Two grades of bolt are commonly used. These are grade 4.6 and 8.8.
Reply:Originally Posted by rlitmanYou're talking in metric.  In SAE grading, grade 8 is roughly equivalent to metric grade 10.9.
Reply:For holding a bumper on, it won't make a big difference what you use. If it was a bumper on a semi that would be pulled on a lot, it might make a difference.
Reply:Originally Posted by Welder DaveFor holding a bumper on, it won't make a big difference what you use. If it was a bumper on a semi that would be pulled on a lot, it might make a difference.
Reply:Originally Posted by BrooklynBravestTo clarify I am using SAE.I'm pretty satisfied with the job I did lining these up. It usually doesn't go off without a hitch when I do this stuff. (No pun intended)Frame is drilled, brackets are done.Only piece left is the plate for the outside. My question, is 1/8 sufficient for this or should I use 3/16? I have a piece of 1/8 so it would save me a couple bucks.
Reply:Originally Posted by SandyIs that plate for the outside going to create a trash trap? I'd have to leave it set there and think about it before I did it.  I do that kind of thing, go walk around, come back and stare at it. What's the plate gonna do for me, or against me?
Reply:Originally Posted by BrooklynBravestHuh?It's just acting as a large washer to sandwich the frame. It isn't going to collect anything?
Reply:Figures, I was soooo close to having it good to go for paint. I tacked the brackets on 1/4 too high and the step portion that the tire fits into hit the cross member. Had to use the BFH to smash them out now I have to grind the tacks down.www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:It fits! Not the greatest weld, I'm not so good with awkward positioning, was good to get some practice.Attachment 1065101www.FirehouseFabricators.comZachLincoln 210mpLincoln SW200Hypertherm Powermax 45xp2x4 CNC Plasma Table.
Reply:The frame rails will yield long before either of these bolts fail but if you wish to put grade 8 do it, in fact you may wish to recheck for lower yield stength because of this oem never use had 8 but if you are worried sabot corrosion go stainless Sent from my SGH-I747M using Tapatalk