Custom Bumper Project

[Marlin]

Marlin, I really hope you are happy with the end result.
That is what matters most.
Having said that, I think you should get someone from a local 4wd club have a look at your setup, and advise on how to beef up the anchor points for your strap, and the anchor points back onto the chassis.

Most official 4wd clubs have very strict rules that apply to towing points.
If you have ever seen what damage a snatch strap can do when one end breaks loose, you would understand why.

Looking good or not, being able to safely use it is a totally different matter.

I am talking from experience, and only with concern about the safety of your trail mates in mind.

Best regards

PK

Hmmm, I did not know that, but I was thinking about how Warn bumpers, and Hummers have their tow points on the bumper. My steel is actually almost double the strength of the Warn bumpers, and those D rings are rated to 10K lbs. They are mounted double walled with 1/2" grade 8 bolts, not sure you can get any stronger, I suppose to I could weld a bback plate to the tubing? The other good thing is that I can just disconnect the hooks and move them back to the factory tow points in a few seconds, just 1 cotter pin each

Thanks for the heads up, I am sure Joe Darlington will look at it with great scrutiny when we get to Uwharrie in Oct. If you don't know who Joe D is, he does a lot of fab works for Isuzu, including Tie rods, tie rod shields, bumpers, sliders.....and the list goes on. I am interested in what he recommends as well.
Thanks again PK

[Triathlete]

I would use a weld on type that the shackle connects dirrectly to...less parts to fail!


For bolt on I would use something like this

and have a solid plate behind it sandwiching the bumper material. This will help prevent the bolt heads from pulling through. Might be overkill but better safe than sorry!

And I am pretty sure you said you were doing so but just incase...high quality grade 8 bolts ONLY!

[Marlin]

I would use a weld on type that the shackle connects dirrectly to...less parts to fail!


For bolt on I would use something like this

and have a solid plate behind it sandwiching the bumper material. This will help prevent the bolt heads from pulling through. Might be overkill but better safe than sorry!

And I am pretty sure you said you were doing so but just incase...high quality grade 8 bolts ONLY!

Shoulda coulda woulda....I went with bolt on type, grade 8 bolts, not sure if I need the plate on the back, the wall thickness on the tube is 3/32", that is some pretty thick stuff. I do have about 3/8" of bolt left, so I may add it later.

[PK]

Hmmm, I did not know that, but I was thinking about how Warn bumpers, and Hummers have their tow points on the bumper. My steel is actually almost double the strength of the Warn bumpers, and those D rings are rated to 10K lbs. They are mounted double walled with 1/2" grade 8 bolts, not sure you can get any stronger, I suppose to I could weld a bback plate to the tubing? The other good thing is that I can just disconnect the hooks and move them back to the factory tow points in a few seconds, just 1 cotter pin each

Thanks for the heads up, I am sure Joe Darlington will look at it with great scrutiny when we get to Uwharrie in Oct. If you don't know who Joe D is, he does a lot of fab works for Isuzu, including Tie rods, tie rod shields, bumpers, sliders.....and the list goes on. I am interested in what he recommends as well.
Thanks again PK

Hi Marlin,
I have just gone back through all your photos and would like to offer the following -
The hook bolts pass through your SHS tube without anything to stop crush of the steel tube. You need to weld some steel tube (round) spacers from the front edge of the SHS to the rear edge. This will spread the load over both of the section areas of the SHS. Alternatively, weld a pad, full height of the SHS and about 6mm (1/4") thick, wide enough to pick up both of the bolts for 1 hook.

The lynch pin points do not look man enough or the loads generated on the front and rear of the respective holes. They look as though the holes will elongate. I would either double the number of pins, or weld pads onto the outside of the outer tube, and inside of the inner tubes, to increase the load bearing area.

The bolt point to the chassis looks to be only one bolt per side for your main attachment point. This would bring into question, the strength of the bolts in shear, and again, the load bearing area of the tube to prevent elongation.


Mind you I have not crunched the numbers because I don't have enough information on the materials you have used.
Most snatch straps used these days are rated at a SWL of 8000kg (17,640 lbs). You need to design so that if anything breaks, it is the strap. A flying strap can hurt - even break bones, but put a lump of steel on the end of it, and it can kill.
From a design point of view, we would use a safety factor of 2:1, so your design strength needs to be capable of supporting 35K lbs.

If you had 16 - 17 tons hanging from your arrangement, would you walk under it??

Please accept above points as a genuine attempt to help.

Regards

PK

[Marlin]

Hi Marlin,
I have just gone back through all your photos and would like to offer the following -
The hook bolts pass through your SHS tube without anything to stop crush of the steel tube. You need to weld some steel tube (round) spacers from the front edge of the SHS to the rear edge. This will spread the load over both of the section areas of the SHS. Alternatively, weld a pad, full height of the SHS and about 6mm (1/4") thick, wide enough to pick up both of the bolts for 1 hook.

The lynch pin points do not look man enough or the loads generated on the front and rear of the respective holes. They look as though the holes will elongate. I would either double the number of pins, or weld pads onto the outside of the outer tube, and inside of the inner tubes, to increase the load bearing area.

The bolt point to the chassis looks to be only one bolt per side for your main attachment point. This would bring into question, the strength of the bolts in shear, and again, the load bearing area of the tube to prevent elongation.


Mind you I have not crunched the numbers because I don't have enough information on the materials you have used.
Most snatch straps used these days are rated at a SWL of 8000kg (17,640 lbs). You need to design so that if anything breaks, it is the strap. A flying strap can hurt - even break bones, but put a lump of steel on the end of it, and it can kill.
From a design point of view, we would use a safety factor of 2:1, so your design strength needs to be capable of supporting 35K lbs.

If you had 16 - 17 tons hanging from your arrangement, would you walk under it??

Please accept above points as a genuine attempt to help.

Regards

PK

Great advice, I was already planning on placing another sleeve inside both ends of the tubes for the tow points. That will prevent the crushing of the tubes. I can easily drill another set of holes in order to double pin the outer sleeves to the inner sleeves.
As for the frame bolts, there are two, I used the factory bumper mounting points as well as the factory bumper bolts. I think they are 17mm grade 8? They go through the 1/4" plate that makes up the front of the frame bumper bracket.
I think at that point, the weakest spot on the whole set up would probably be the bolts for the tow points. But as I mentioned earlier, I can move the tow hooks from "my" points to the factory points in less than 10 seconds, I left them accessible on purpose. So if I am buried in mud doing some serious snatching, then I can move the tow hooks. If it is normal, stuck on an obstacle, just need to move snatching, then I can leave it. I plan on going out to the woods when I am done and tying off to a big tree. Then I will slowly back up with a buddy watching to see if anything moves, if it does, that is the next thing to upgrade. This way I can test it in a controlled environment without danger to anything or anyone. Tree huggers may be upset, I will be stressing out a tree.....

[Robbomaz]

Hmmm, I did not know that, but I was thinking about how Warn bumpers, and Hummers have their tow points on the bumper. My steel is actually almost double the strength of the Warn bumpers, and those D rings are rated to 10K lbs. They are mounted double walled with 1/2" grade 8 bolts, not sure you can get any stronger, I suppose to I could weld a bback plate to the tubing? The other good thing is that I can just disconnect the hooks and move them back to the factory tow points in a few seconds, just 1 cotter pin each

Thanks for the heads up, I am sure Joe Darlington will look at it with great scrutiny when we get to Uwharrie in Oct. If you don't know who Joe D is, he does a lot of fab works for Isuzu, including Tie rods, tie rod shields, bumpers, sliders.....and the list goes on. I am interested in what he recommends as well.
Thanks again PK

Great work so far If I may put in 2c?
My first thought was with your snatch points where they are - wide apart and on the ends of your extensions - there would be a degree of leverage 'crush' force trying to pinch the two together during the snatch. Whether you would actually get any movement I dunno, but with the hitch points closer together the effect would be less.
I've seen a snatch by an expert using the factory designated points kink a chassis leg in
As I said, just my first thought, feel free to slap me
Rob

[Marlin]

Great work so far If I may put in 2c?
My first thought was with your snatch points where they are - wide apart and on the ends of your extensions - there would be a degree of leverage 'crush' force trying to pinch the two together during the snatch. Whether you would actually get any movement I dunno, but with the hitch points closer together the effect would be less.
I've seen a snatch by an expert using the factory designated points kink a chassis leg in
As I said, just my first thought, feel free to slap me
Rob

Wow, I never thought about that? How do the hummers and Jeeps get away with using tow points that far apart? Hopefully the gussets I weld in this week will add enough stability to minimize the potential damage. This is another reason I love this site. I ahve never done anything like this before, and I am getting all kinds of feedback.
Some I will upgrade, some I think are not needed, but all are important, so if my setup fails, you can say "I told you so!!"
Then I get to rebuild...yipppeeeee!!!!!!!!!!!!!!!!!!!

[Triathlete]

Although not structural as you said you may want to build that grill hoop as if it is. If you have a minor front end collision that hoop will bend into your hood/grill causing more damage than if you didn't have it. Just ask anyone that has had an accident with a safari bar in the front.

[vt_maverick]

Although not structural as you said you may want to build that grill hoop as if it is. If you have a minor front end collision that hoop will bend into your hood/grill causing more damage than if you didn't have it. Just ask anyone that has had an accident with a safari bar in the front.

I thought the whole point of safari bars was to PROTECT the front of the car?

[Triathlete]

Nope, Safari bars (aka brush gaurds) are pretty much cosmetic. They will move light brush out of the way but thats about it.

[Marlin]

Nope, Safari bars (aka brush gaurds) are pretty much cosmetic. They will move light brush out of the way but thats about it.

Yep, I know that, saw someone rip the guard off the front of their rodeo in NC, tried to warn them....but they wouldn't listen.

As far as making my hoop "structural", I dunno, if I drove around worrying like that, I would never move it out of my driveway, if I get into a front end collision with something big enough to get up that high, I am screwed and it is totaled anyway.
ALthough it would give me a reason to get a 12ton press to bend tubing with.....my garage is starting to look like a metal shop.

[Robbomaz]

Wow, I never thought about that? How do the hummers and Jeeps get away with using tow points that far apart? Hopefully the gussets I weld in this week will add enough stability to minimize the potential damage. This is another reason I love this site. I ahve never done anything like this before, and I am getting all kinds of feedback.
Some I will upgrade, some I think are not needed, but all are important, so if my setup fails, you can say "I told you so!!"
Then I get to rebuild...yipppeeeee!!!!!!!!!!!!!!!!!!!

Were it me, I'd put them just inside the width of the chassis rails apart, but it looks like you have a lot of metal in there, should be plenty strong I'm watching this closely, I have to either buy a roo bar for my project (ho hum everyones got one of those) or do what you're doing

[Marlin]

Were it me, I'd put them just inside the width of the chassis rails apart, but it looks like you have a lot of metal in there, should be plenty strong I'm watching this closely, I have to either buy a roo bar for my project (ho hum everyones got one of those) or do what you're doing

No way I would go with ordinary, run of the day stuff. I have had a lot of fun making this thing, and I cannot even begin to tell you how much I have learned. Metal work is a whole new world for me. I think it moght be addictive, I find myself walking around the house thinking "I could fab something for that" "I oucld weld that together".
I am going to make the pretty pieces this afternoon out of cardboard and post up some pics to get advice, I will also go ahead and sleeve the inserts for the tow points, and drill out second holes for another set of pins. The gussets can wait until I do the body work. That should satisfy just about everyone
Then I will tie it to a tree, pull the tree out of the ground, destroy the tranny and break a few straps, just to prove that my bumper was not the weak point!!! LOL.

[Marlin]

First upgrade complete. I put the 2" tubing sleeved into the crossbar for the tow points. Took forever, that is a whole lot of steel to drill through, and the bit is about $15. I made the sleeve about 10" long, so that should do plenty to spread the force over a bit wide of an angle, as well as strengthen the weld point. Thanks for the advice guys. I gotta find a scrap yard so I can get materials to make the gussets with.

[Marlin]

Update*** I am upgrading the clevis pins to 5/8" hitch pins this weekend, and I decided to take Billy's advice and get some bolt through D-ring shackles. By autocad, the weakest point will be about 20K lbs at the welds on the tubing. The front portion of the frame will bend before the bumper does, assuming the welds are good.
For the metal work guys, the inner tube is 8gauge, and the outer tube is 12 gauge.
I will post up the pics of the new shackle mounts, that may be a few months, but the pins are this weekend for sure, as well as some of the sheet metal work. I got my LED turn signals in, and picking up the driving lights Friday. HID kit for those will be in August sometime. I may not do the whole front end in sheet metal, it is starting to grow on me Just do the bottom and sides so it looks a little tighter, and a front facia for the lights and to hide the tubing. I don't know what to do next I am running out of projects. Any ideas? I may get the hubs this weekend too if it isn't 100 degrees and raining.