drilling holes into front of frame

[looch]

I am in the process of building a front bumper and would like to incorporate a reciever for a hitch into it. My current thoughts are to cut a square hole in the bumper, slide the reciever through(premanufactured seamless tubing with hole for pin), weld a backing stip with two holes onto the reciever, drill to holes into the front frame, and bolt the backing stip to the frame. I was wondering if doing this would weaken the frame. Do you suppose if I just welded the front and back of the reciever to the bumper (3/16" mild steel) that it would be strong enough?

[ArtsiFrtsi]

:D I don't think that it will weaken it any, after all, how many holes are there not being used as it is? I would weld the front of it to the bumper, and bolt it to the frame as well, then you'd have another mounting point for the bumper, and the bumper would also help to hold the receiver on the vehicle. :D

[oldyellowwagoneer]

If you bolt it to the frame you shoule drill out the holes large enough to sleeve them with pipe to avoid collapsing the frame. Weld the pipe front and back to the frame. Be carefull when you drill since there's a brake line running alongside the frame. DENNIS

[Tad]

I think welding the reciever tube to the 3/16" front bumper would be just fine. You might be jerking someone out backwards and that creates a lot of stress but I think your OK. Now if you want to tow something backwards at say 50mph...that's another story.

[looch]

Tadsal--I am going to put the receiver on so that I can eventually ($$$$) use it with a winch cradle. Do you suppose that the bumber could handle that?

[Tad]

1. What size tube is the bumper going to be made of? (3/16 x ? x ?)
2. Are the bumper mounts going to come straight foward off the frame and what size are they?
With that information I can calculate the approximate tensile strength.

[looch]

Tadsal--I am using 3/16" plate that with a 90 degree bend up top and a 45 degree bend on bottom. The front "face" of the bumber is 5" tall, the bottom bend is 1", and the top is cut to fit the point of the front clip (from 4" to about 1 1/2") The mounts are 1/4" x 3" x 8" bent in half with the front half welded to the flat back of the bumber all around. Thanks for you help---

[Tad]

OK, how much you cut for the clip of the wag beyond the first 1/2' of the top 90 degree bend won't matter that much. I'll print your numbers and do some math on the actual surface area the tube will be attached to. I think, just reading this, that you'll need to tie the back of the reciever tube to the frame or back out to near the mounting plate on the backside of the bumper. Me do math, get back in am.

[looch]

Thanks Tadsal! Tying into the mounts might not be a bad idea. I hadn't even thought of that. Maybe I could extend some sort of brace from the backside or underside of the reciever to the mounts? tongue.gif It is pretty tight back there (with the V-cut and all), but I might just be able to weld a piece of tubing from one mount to the other and then tie in the reciever. Two heads are definately better than one. Thanks again.

[JB]

looch , when you get done with the project , If its not too much trouble I would like the deminsions and lengths of materials used , thanks JB

[Tad]

looch -
The compression and tensile strength of mild steel is 15,000 lbs per sq" of surface area. In your case the surface area is only the 3/16" of the 90 degree bend above the area of the tube, I'm not counting the bottom bend since it's not 90 degrees and will not have that much more strength to add. Using that formula, (there are others), we get a max tensile strength of about 5,600 lbs, a SWL (safe working load) would be 1/2 that, 2,800 lbs.

This is what I suggest, I am by no means an expert, just a humble welding teacher.

On the back side of the bumper, use a section of 1/4" plate extending as far as you can towards the frame, by welding this to the back of the bumper you can increase the SWL by about 7,500 lbs for a total of 10,300 lbs.

The tie the back of the receiver to the outer ends of the 1/4" plate using the same 1/4" x 3" material you are using for the mounts. This will add about another 5,500 lbs of SWL.

You'll now have a receiver area with about 15,800 of SWL, that's stronger than the receiver insert tube and probably max for what the frame can take.

[Tad]

Math in the morning, never do that again????