Frame reinforcement ??

[MAC71]

I am thinking about doing some frame reinforcements. I want to just stiffen it up a little with out adding to much to the frame. Leaning to just adding some gussets to the cross members and maybe welding the cross members in.
Any thoughts or ideas.

Here is some photos of card board templates to give an idea of what I am thinking.

[imjeff]

I'm curious why? There has to be some flex points or you'll start breaking and cracking parts. Those gussets would keep the frame from racking corner to corner, but so does the body.

Jeff

[TrkEnvy]

I beg to differ.. The frame should not flex at all. The suspension should be doing all the work, but if factories had built us super rigid race truck frames then they would have been way out of the average consumers price range. So, while I think it's a good idea to limit flexion, until your frame rails are boxed the entire length you are wasting your time with gussets.

[imjeff]

What "flexion"? I don't see many truck frames racked corner to corner, but I do see them with cracks from welding. The gussets pictured are not on the same axis as boxing.

[67chevy1series]

As far as frame flexing being good or bad,the 2014 GM trucks for sure have fully boxed frames and tubular crossembers to eliminate flexing. I know GM, FoMoCo, and Dodge have been trying there hardest to build there frames not to flex as you always see them drive the truck up on frame twisters and try to show that the frame doesn't flex, the body aligns almost perfectly and that the tailgate and doors still open and close with nice gaps and operate normally while one rear wheel is off the ground. Not only that but after watching a lot of porterbuilt equipped truck builds, those truck frames are pretty much entirely mated with bolts which don't flex like rivets do. The only things that I can see being a bad thing is if you've welded you front clip together as a whole or if you welded the tailgate up to the bedsides, if any of that has been done I would assume there would be some body issues appearing after driving. Not saying stock suspension is up to the task of being the only flexing part of the truck

[brad_man_72]

I've been wondering about bolting the cab to the bed (with large spacers to keep the gap correct and act as a fender washer to keep the metal from tearing). Poly body mounts reduce flex aslo. The only way to keep a frame from flexing is to build up, frames are pretty much a flat plane, add a third dimension (height) and it will stiffen significantly.

[imjeff]

Originally Posted by 67chevy1series

As far as frame flexing being good or bad,the 2014 GM trucks for sure have fully boxed frames and tubular crossembers to eliminate flexing. I know GM, FoMoCo, and Dodge have been trying there hardest to build there frames not to flex as you always see them drive the truck up on frame twisters and try to show that the frame doesn't flex, the body aligns almost perfectly and that the tailgate and doors still open and close with nice gaps and operate normally while one rear wheel is off the ground. Not only that but after watching a lot of porterbuilt equipped truck builds, those truck frames are pretty much entirely mated with bolts which don't flex like rivets do. The only things that I can see being a bad thing is if you've welded you front clip together as a whole or if you welded the tailgate up to the bedsides, if any of that has been done I would assume there would be some body issues appearing after driving. Not saying stock suspension is up to the task of being the only flexing part of the truck

I was assuming the design specs, steel and suspension technology were different in 2014 than 1970. I also assumed that boxed frames were to gain strength on a different plane than the pictured gussets. Since I don't have a porterbuilt anything, I guess I'm out of the loop. Like I said, I've never seen a truck frame spontaneously rack itself, but it sounds like I must be mistaken. Weld away, I say. I will continue to drive my BBC K 10 every day, at least until the frame racks into a diamond.

[Fatherflash]

With the understanding that manufacturing knowledge has grown greatly since the 1960's/1970's, anytime you reinforce a frame whether through gusseting or boxing, the loads are transferred to areas that may have not been considered during the design of that frame. What that means is if you gusset, you strengthen the frame however, you also transfer load to other points of the frame that may not have been designed to take that load.

Unless you fully box and all open areas and gusset every location, you are just transferring load and stress from one location to another. When you transfer stress or load to a location that may not be able to take that load or was designed to absorb load (not something common when our trucks were manufactured), you are introducing stress to areas that may not be capable of taking those loads which could lead to failure at those locations. Nothing quite so exciting as having a frame fail during a critical moment.

Simply put, you gusset a frame cross location with fasteners, you transfer the torque loads from the cross beam to those puny fasteners. That cross beam is designed to flex and if you dampen that flex, all the loads created during either acceleration or turning will be at the fastener locations which if you are lucky will wear and let you know they are about to fail. if you are unlucky, those fasteners will fail at the absolute worse moment and if you are still lucky, you will walk away from that failure. Most welds can take stress loads however, they are not that terrific at taking shear loads over time which torque frequently produces.

My opinion: Gusset and box everything or leave it alone.

[trkfrk]

Originally Posted by Fatherflash

With the understanding that manufacturing knowledge has grown greatly since the 1960's/1970's, anytime you reinforce a frame whether through gusseting or boxing, the loads are transferred to areas that may have not been considered during the design of that frame. What that means is if you gusset, you strengthen the frame however, you also transfer load to other points of the frame that may not have been designed to take that load.

Unless you fully box and all open areas and gusset every location, you are just transferring load and stress from one location to another. When you transfer stress or load to a location that may not be able to take that load or was designed to absorb load (not something common when our trucks were manufactured), you are introducing stress to areas that may not be capable of taking those loads which could lead to failure at those locations. Nothing quite so exciting as having a frame fail during a critical moment.

Simply put, you gusset a frame cross location with fasteners, you transfer the torque loads from the cross beam to those puny fasteners. That cross beam is designed to flex and if you dampen that flex, all the loads created during either acceleration or turning will be at the fastener locations which if you are lucky will wear and let you know they are about to fail. if you are unlucky, those fasteners will fail at the absolute worse moment and if you are still lucky, you will walk away from that failure. Most welds can take stress loads however, they are not that terrific at taking shear loads over time which torque frequently produces.

My opinion: Gusset and box everything or leave it alone.

Agree 100%. I thought I was reading a suggestion from one of my mechanical engineers at work. Lol

[SS Tim]

The easiest way to imrove a C10 frame is to replace it with a C20 frame. The section height and thickness increases make the frame about 25% stiffer. The beefed up bracketry and trailing arms can only help.
But as others have pointed out just welding is going to transfer stress and that is not always a good thing.
At this stage a frame swap would be super easy stripped as it appears.

C Blazer
C10 115"
C10 127"- 6.04" section height, 2.53" flange width, 0.156" thick, 2.98 section modulus

C20 127"- 6.11" section height, 2.46" flange width, 0.194" thick, 3.71 section modulus

C20/30 133" (Longhorns)- 7.20" section height, 2.77" flange width, 0.194" thick, 5.05 section modulus

C30 157"- 8.18" section height, 2.97" flange width, 0.224" thick, 7.29 section modulus