Frame Welding Do's and Dont's (Thanks Nick)

[Jasonj105]

First I want to start by thanking Nick (BrokenBronco) for directing me over to this forum. But my question is about fishplating and welding to Bronco frames. I am connecting my cage to the frame, and doing shock hoops and an engine cage. I want to weld a 3/16 plate anywhere to the frame I will be attaching any kind of tubing, but I ve been told not to weld perpendicular on the frame. Can anyone clarify how the plate should be welded.

Thank you.

[billy1911]

You can but after some heavy abuse it will most likely crack. Not on the weld but the heat effected between the weld and the native material. the best thing to do is box the frame. Make sure the plates you use to box the frame are longer then your landing plates. This will help but eventually it will crack.

[billy1911]

Also you can make the landing pads trapezoid not square.

[SteveG]

I've always been told that you should either not weld at all or weld A LOT to ford truck frames (because of their tempering). Especially on the face.

You could also make it all bolt-on like this tuck:

http://www.race-dezert.com/forum/showthread.php?t=68264

EDIT: I should have added that there are perfectly good exampled of cages done both ways.

[Rednek Renegade]

So me welding my leaf spring brackets to the frame will actually weaken it?

[philofab]

So me welding my leaf spring brackets to the frame will actually weaken it?

Possibly. If you have vertical welds across the face of the frame it may crack next to the weld.

This is the reason all of the 80s and 90s Ford race trucks had bolt on or bushing mounted cages. Ford specifically told racer NOT to weld on the frame. This does not matter if you have a cage from front to rear that is solid mounted. You have to be careful not to create any one area that sees an excess of force or rigidity.

[ntsqd]

A change in cross section, like in adding a welded-on plate or a hole for that matter, is a stress riser. What ever you do, the idea is to mitigate that as much as possible. How ever you shape the edges of the plates, you can pass through running straight vertical, just don't dwell there.

[Rednek Renegade]

So since my welds wouldnt be going straight up and down but at an angle they would be okay?

[gunit]

I welded mine in both areas discussed, no frame cracks yet (Although plenty elsewhere).

Here are the pics

frame mount.jpg (20.02 KiB) Viewed 3594 times

spring mount.jpg (69.06 KiB) Viewed 3594 times

[PaulW]

Maybe you guys should examine a few Broncos with cages. No plates just tubes that fit, and plain old butt welds. My Bronco has over 10k miles on Baja roads and whoops and several others have 2 to 3 times that many miles. No weld or cracks found. Most of the cracks seem to be at the cage tube penetration to the body where thin metal and thick tubes are welded. We strive to eliminate body flex but these body cracks indicate we are not completely sucessful. We do know there are very few of these cracks.
It is possible all these Broncos I know of are done by a pro with proper weld material and correct heat. All are mig welded.
PW

[Jasonj105]

Miesk5 posted this on that old sight we used to be one, the name slips my mind, lol.

"Bronco Frame 1992 (other years similar)
Frame Service - Drilling Precautions
CAUTION: Do not drill holes in the frame flanges. This will reduce the strength of frame (5005).
If a hole must be drilled in the frame, make sure that it meets all of the following requirements:
1. The hole is located in the upper half of the frame.
2. The edge of the drilled hole and the edge of the nearest hole are at least 25mm (1 inch) apart.
3. The edge of the drilled hole is at least 25mm (1 inch) from the edge of the flange.
4. The drilled hole is not adjacent to any other existing brackets or components of frame.
Welding Precautions
CAUTION: Disconnect the battery ground cable (14301) before using any electric welding equipment.
All welding on frame must be done with electric welding equipment, and the heat should be kept in a small area to prevent change in hardness of the metal. Do not use gas welding equipment. A double reinforcement must be added to frames where heat or weld is applied to the area to be repaired. The welds are to run lengthwise along the reinforcement when a reinforcement is to be welded to the frame side rail.
Frame Strength Identification
F-Series, F-Super Duty Chassis Cab and Bronco all use a 36,000 psi steel frame.
Frame Straightening
Misalignment of frame can be corrected by straightening the out-of-line parts or by replacing the crossmembers, braces, or brackets if they are badly damaged.
WARNING: DO NOT STRAIGHTEN FRONT FRAME RAIL CONVOLUTES.
Straightening should be attempted on frames that fail to meet specifications of the diagonal checking method or where damage is visually apparent.
However, to prevent internal stresses in the metal, frame straightening should be limited to parts that are not severely bent. If heat is needed to straighten a frame member, keep the temperature below 649�C (1200�F) (a dull red glow). Excessive heat may weaken the metal in the frame members and cause permanent damage.
Frame Reinforcing
After a bent frame member has been straightened, inspect the member closely for cracks. If any cracks show, the frame member should be reinforced or replaced.
Reinforcements should be made from angle or flat stock of the same material and thickness as the frame member being reinforced, and should extend a minimum of 152.40mm (6 inches) to either side of the crack. Ideally, the reinforcement should be cut from the corresponding area of a similar frame.
Weld Attachment
To ensure a quality repair, adhere to the following procedure if it is necessary to weld reinforcements to the frame.
1. Wire brush the area around the crack to remove the paint, grease, mud, etc., and to expose the crack completely and ensure good weld adhesion.
2. To stop the crack from spreading, drill a 6.35mm (1/4-inch) hole at a point 12mm (0.50 inch) beyond the root of the crack.
3. Grind out the full length of the crack to the hole to form a V-shaped slot with the base of the V-slot contacting the reinforcement.
4. The base of the V-slot should have at least a 1.52mm (0.06-inch) opening to ensure weld penetration to the reinforcement when welding the crack.
5. Drill clearance holes in the reinforcements to clear rivet heads and bolt heads or nuts where necessary.
6. In the event that repair is required on more than one frame surface (i.e., a flange crack that extends into the web), two pieces of flat stock (one for each surface) should be utilized and welded together where they join. The web reinforcement should be a minimum of 76.20mm (3.0 inches) high and have a 63.50mm (2.5-inch) radius at each of the two corners.
7. Completely clean the surface of frame under and around the reinforcements.
8. Clamp the reinforcements securely to the frame prior to welding.
9. Weld the reinforcement all around after welding the crack V-slot.
10. The flange edge weld should be ground smooth after all pit holes have been filled by the weld.
11. If a damaged bolted-on frame bracket is to be replaced, the new bolts, washers, and nuts should be of the same specifications and bolt torques as the original parts.
12. In cases where it is necessary to remove rivets, replace them with Property Class 9.8 metric (Grade 8 ) nuts, bolts and washers of the next larger size (i.e., for 3/8-inch diameter rivets use 7/16-inch bolts, for 7/16-inch diameter rivets use 1/2-inch bolts). This requires line drilling of the holes to the same diameter as the new bolt (i.e., either 0.437 diameter or 0.500 diameter).
Frame Member Replacement
If a damaged frame member is to be replaced, new bolts, Property Class 9.8 metric (Grade 8 ) fasteners and rivets required for replacement of parts should be of the same specifications as the original bolts or rivets. In cases where it is necessary to substitute a bolt for a rivet, use the next larger size bolt."
__________________

[MOSS2]

One item that may be of interest here is when bolting items to the frame using a short bolt can be a disadvantage. We have found short bolts as in bolting thin frame to thin plate are really hard to keep tight even if torqued properly. The same joint with thick washers and a little longer bolt holds up just fine. The reasoning is a longer bolt offers more stretch and has to relax a lot more to lose tension and come loose. The length you need increases with the diameter of the bolt. I will try and find some technical backup for this as I have probably stated some part of this incorrectly

[ntsqd]

One of the small things that has puzzled me about GM's steering box mounting on my Sub is the use of spacers on the inside of the frame 'C' rail, and the required longer bolts. I figured that it was not an accident, but hadn't been able to conjure up a reason why. Moss2's post makes complete sense to me. FWIW those steering box bolt spacers are ~1" tall.

[magic carpet XLT]

Most of the cracks seem to be at the cage tube penetration to the body where thin metal and thick tubes are welded. We strive to eliminate body flex but these body cracks indicate we are not completely sucessful. We do know there are very few of these cracks.

this is the only place where my cage has developed cracks over the years. butt welds can be plenty strong if done properly and the cage is of a good design.

how many of you have issues with roof cracks? mine are horrendous, and i haven't yet found the way to eliminate them.

[philofab]

Most of the cracks seem to be at the cage tube penetration to the body where thin metal and thick tubes are welded. We strive to eliminate body flex but these body cracks indicate we are not completely sucessful. We do know there are very few of these cracks.

this is the only place where my cage has developed cracks over the years. butt welds can be plenty strong if done properly and the cage is of a good design.

how many of you have issues with roof cracks? mine are horrendous, and i haven't yet found the way to eliminate them.

Are you referring to the area on the top passenger and top driver side where the hardtop mounts? You have to have a very stiff cage attached heavily to the B-pillars similar to Leduc and Southwest cages. Unfortunately the design of out trucks creates a huge pressure point on the body at that location.

[PaulW]

Both my Broncos and others built by Glen are fully unitized. Meaning the cage and body are welded together. Bed rail stitch welded to the lateral from the B to the C. The A to b at the top same. The A cage tube follows the body A and they are stitched together. No more issues there , just where the tubes penetrate the body - firewall, floor, etc. So far mine has no cracks.
PW

[jennydinc]

That is a good information about welding precautions. It is better to take those necessary precautions always to stay away from a hospital.pacquiao vs clottey live

[KBL]

I've got some close-up photos of a Bronco owned by Lee Hayes which was built by Curt LeDuc.

As mentioned, the body is welded to the 'cage. The 'cage and suspension bolt to the frame--no direct welding.

This rig was amazing, although on paper it doens't sound like anything that would blow you away. It had stock-width beams and a stock-width rear axle, and full frame rails. Suspension travel wasn't anything eye-opening, at 16 inches front and rear. The amazing part was how well it worked and how much abuse it could take.

Here's how Curt tied the front and rear suspension mounts together:

Lee-Hayes-Bronco-19.jpg (89.56 KiB) Viewed 3297 times

A couple of shots of the juncture at the cab and the fiberglass top:

Lee-Hayes-Bronco-56.jpg (123.65 KiB) Viewed 3297 times

Lee-Hayes-Bronco-63.jpg (90.13 KiB) Viewed 3297 times

[KBL]

One more: a bolt-on landing plate with a tube welded to it.

Lee-Hayes-Bronco-68a.jpg (133.81 KiB) Viewed 3297 times

[BDKW1]

Lee's bronco has more miles on it than any other that I know of.

All of the old Walker Ramchargers were bolton/bushing mount on cages. They are still running around this way 20 some years later. Putting a plate on the frame to weld to is a waste of material. If you welded the tube strait to the frame and used some .125 to box it into the frame you would be way ahead of the game. Once you start welding on it, I would highly recommend boxing in the frame with .125 mild cold rolled..........