Bumper Design (1 Viewer)

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marcfj60

marcfj60

Joined
Oct 1, 2006
Threads
206
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4,353
Location
Sandia Park, NM
I've come up with a design for the rear bumper for my 60. I bought all the steel for it this weekend and just need to get to work on it. Now if I could figure out how to survive on about 2 hours of sleep a night, I might have time to work on it. The main tube is a 3 X 6 x 3/16 wall. I got a seamless receiver tube from BDA trailers. All the steel I got lucky and was able to get at Koenig's. The current weight, according to Pro Engineer is 115 lbs. The idea is to have a 99% bolt-on solution without any cutting or welding to the frame. I will just need to drill some holes in the frame rails to mount the tow tab straps.
bumper1.jpg
bumper2.jpg
bumper3.jpg
 
And a couple more.
bumper4.jpg
bumper5.jpg
 
While you are there it can't hurt to cut in some lights.
 
I like it. Low profile, reasonably light, functional. If you don't mind, I'd like to offer two suggestions based the experience with mine.

First is to either recess the receiver into the bumper, or provide it with some sort of reinforcement/ramp below it for protection. I once thought I wouldn't be able to get the pop-up home after wheeling because I deformed the receiver and couldn't get the hitch in.

The other relates to the side "wings". Make sure to leave maybe more clearance from the sheetmetal than seems necessary. You wouldn't think it, but the body mounts can compress enough and frame flex enough that the first time I dragged the rear hard the bumper put dimples in the sheetmetal.

Hope this makes sense.
 
Ruadhrigh said:
sweet.

are the tow tabs going to double as recovery points?
Click to expand...

Recovery points are probably a better description than tow tabs. I'm not sure exactly what profile they should have, how far the hole should be from the end of the tab, how big the hole should be or how far the tab should protrude from the face of the bumper. They will be made from 1/2" plate steel that is 3 1/2" tall. They will penetrate completely through the bumper and stick out about 8" on the 'back' side of the bumper to provide part of the mounting for the bumper. I want to be able to secure D-rings to them for recovery use and remove the tow hook that is currently bolted to the bottom of the frame rail and catches on stuff.

Anybody know off-hand the pin size and D diameter of a typical D-ring used for vehicle recovery use?
 
Cruisergreg said:
First is to either recess the receiver into the bumper, or provide it with some sort of reinforcement/ramp below it for protection. I once thought I wouldn't be able to get the pop-up home after wheeling because I deformed the receiver and couldn't get the hitch in.
Click to expand...

The current design has the receiver tube penetrating through the bumper and being welded flush with the back side. I'm still debating whether to use the flat gusset shown above or to use two triangular gussets welded below the tube and at a 45 degree angle that would act as ramps for anything scraping up from below (or maybe keep the flat and add the triangles). The reason the tube protrudes out so much is because the hitch-pin hole is already in one I bought, about 3" from the end, and I wanted to give enough clearance between it and the bumper face for a locking pin, if necessary. I don't have any idea how much clearance I really need but currently it is 1.25" from the center of the hole to the face of the bumper, the same distance from the center of the hole to either the top or bottom surface of the tube.

Cruisergreg said:
..The other relates to the side "wings". Make sure to leave maybe more clearance from the sheetmetal than seems necessary. You wouldn't think it, but the body mounts can compress enough and frame flex enough that the first time I dragged the rear hard the bumper put dimples in the sheetmetal.
Click to expand...

Good advice. I think I've got about 1 1/2" clearance and the 'wings' will be made from 1/4" thick plate. Hopefully they won't flex much and they will be far enough away from the body to keep from hitting it.

Thanks for the advice based on your learning experiences.
 
marcfj60 said:
Anybody know off-hand the pin size and D diameter of a typical D-ring used for vehicle recovery use?
Click to expand...

I believe the holes on da'40 are 3/4" and I cut them after I acquired the shackles. I would cut them larger (7/8"?). I have another pair of 3/4" shackles that I keep in the truck and they are just a tad too big for da'40.
 
Here are some images with the top gusset removed and two triangular gussets added to the bottom of the receiver tube. I reworked the shape of the recovery tabs as well. Any ideas how large the safety chain ovals should be? In this image they are 1" X 2". That seems too large for the gusset size.
bumper2-1.jpg
bumper2-2.jpg
bumper2-3.jpg
 
One more angle.
bumper2-4.jpg
 
Recess the 2" receiver like Greg suggested and put the pin in from behind the bumper. Take a look at the 4x4 Labs bumper for the 80-Series.
-Mike-
 
Beowulf said:
Recess the 2" receiver like Greg suggested and put the pin in from behind the bumper. Take a look at the 4x4 Labs bumper for the 80-Series.
-Mike-
Click to expand...

The downside to that is that I would have to cut a big chunk out of the crossmember to clear the receiver tube and any additional gusseting. I'm trying to avoid cutting any of the frame.
 
Damn engineers. :rolleyes: you got pictures and cad drawings and...

OK looks way cool, and it took me 2 weeks to make something half as cool.:D
 
Thanks. It's really nice to be able to 'make' something in the virtual world before you actually make it in the physical world. I don't know how engineers designed anything complicated before 3D solid modeling CAD packages came along. They actually had to think and use math.

Anybody with a spare $15k can get a seat of Pro Engineer and make the same pretty pictures I did. Or, for half that you could get Solid Works. I'm lucky enough to get to use the company's license for 'incidental personal use'. Meaning, in the morning before my official start time and during lunch I can use it for personal use as long as I don't use it to make any money and it doesn't impact my work responsibilities.

If I wasn't worried about paying the mortgage or feeding my wife and kids, I'd try to make a living designing and manufacturing bumpers, sliders, skid plates, suspensions, etc.....
 
Not to say they compare to those CAD programs, but there are several free-ware versions out there. Google even has one. I downloaded it, and used it for about 30 minutes. For the at-home weekend user, I am sure they will do the job, just take abit longer.
 
marcfj60 said:
The downside to that is that I would have to cut a big chunk out of the crossmember to clear the receiver tube and any additional gusseting. I'm trying to avoid cutting any of the frame.
Click to expand...

the bumper will be stronger than the original x-member, cut it and forget it.
 
dude,

where are the sliders you were suppose to build up? I'd think you need them more than the rear bumper!!

Just bustin' your chops...
 
I've been kind of busy. Stop busting my chops.

I want to be able to tow stuff and this was the perfect excuse to make that possible. Plus, if I build sliders, I might start wheeling harder and breaking more stuff. A tougher rear bumper will just make me less nervous about the dismal departure angle of an unlifted 60.
 
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