A different approach to a LWB to SWB conversion

[65standard]

I understand everyone's concern about the frame. I have been doing this for nearly 30 years now and have never had a weld crack, even on some very high horsepower trucks. Remember, this is a C20 and the frame rail is about 50% thicker than a C10 frame.

Skinning the rail with a channel that fits inside would be insurance that everyone can see and understand. Welding is still mysterious to most and not trusted with your life. I am a unlimited thickness certified welder. The frame will stay as is. All others please add fish plates and not follow my example here.

[Mayo]

I'm a longbed guy myself but your are doing a fantastic job!

[65standard]

My wife wanted it cut down. She didn't like the look of the long bed. Pressure from her made me convert it.

[kingstrider]

You have some fine fabrication skills, I like how you are doing the bed.

[67c10rustbuket]

Great fab work, I always wondered why no one did the bedsides like this. I am curious how you do the rear half of the bedsides though. You obviously know what you are doing and I understand the difference in frame welding from a guy with a welder like me to a real cert welder like you. Keep up the great work.

[imjeff]

No need to get defensive, I just don't want anyone else thinking this is the proper way to weld a frame. Welding is not a mystery to me. If we're throwing experience out I will tell you I've been welding for about 40 years, but a journeyman for only about 30 of that. I have a fair amount of both formal training and experience with heat treating techniques and practical experience pertaining to a variety of metal, including mild steel. To not acknowledge the change in space lattice and the resultant vertical stress points just doesn't make sense. Without heat treatment that frame is weak on each side of the weld. Not opinion, fact. Either most every frame shop in the nation doesn't possess your talent or fish plating is an industry standard for a reason. I appreciate your craftsmanship, but would not do a frame like that anywhere but maybe the ends. I hope anyone else doing this consults more sources before they proceed. Good luck!

[Andy4639]

The weld is the same type of weld used in piping. Nuclear plants and any other plant use full pentration welds with beveled ends. No difference. Nice job man. Being a common weld with QC inspections for the full penitration. Certified welders can do this with no problems. As stated most people are not going to be certified in this type of welding. It takes years to gain this type of certifaction. It takes even more practice to keep it.

[imjeff]

Originally Posted by Andy4639

The weld is the same type of weld used in piping. Nuclear plants and any other plant use full pentration welds with beveled ends. No difference. Nice job man. Being a common weld with QC inspections for the full penitration. Certified welders can do this with no problems. As stated most people are not going to be certified in this type of welding. It takes years to gain this type of certifaction. It takes even more practice to keep it.

As one who has the certification I will tell you this is not the same as nuke piping. Mild steel isn't used in nuke piping. Nuke piping is welded with TIG. It's generally not steel period. There are many types of welded assemblies that are require fullpenetration welds. No mystery there. The toes are an issue. There's a reason for fish plating and its not because no one has enough expertise to do it. It's because the heat put into the steel causes the toes to become brittle. That's why heat treating exists. The steel in a weld is stronger than the base material, but the adjacent steel undergoes changes that induce internal stress in the steel and it becomes the failure point. Once again, this isn't a welder ability issue, this is metallurgy. If you can tell me the weld technique that leaves the space lattice of the toe unchanged I will be happy to try it. Unfortunately, welding puts heat into the base material and that changes its characteristics. Not my opinion, fact. If the truck is ran like most trucks these days it may very well be ok, but if it fails it will be next to those welds, even if they're perfect. I won't argue it further as its not a subjective issue, but since you brought nuke plants into it I thought I'd respond.

[68shortwide]

Okay, can we stop the pissing match and get back to the "outside of the shortbox" thinking here? The man has talent and great imagination, Lookin forward to more

[WIDESIDE72]

Curious about bed rear as well.

[29od1]

Any of you certified welders know what the reduction in material allowables is due to welding? We could do a quick axial and bending calculation on the frame and see if it's anywhere close to Fty. My guess is that with a good weld and a 3 ton load at the rear bumper, it should be no problem with a C20 frame.

At least the analytic calculations would stop the conjecture whether it will fail or not.

I think this method of cutting down a LWB could save a ton of welding and body work. I can't wait to see the final product and how you tackle the hardest part.

[Vintage Windmills]

Originally Posted by imjeff

The steel in a weld is stronger than the base material, but the adjacent steel undergoes changes that induce internal stress in the steel and it becomes the failure point. Once again, this isn't a welder ability issue, this is metallurgy.

True statement.

Maybe since its a thicker frame than any Swb that ever left the factory with, it will have stresses low enough to not be an issue, but so much of it depends on usage (loads and miles driven). A fishplate or formed channel insert just seems like cheap insurance.

I like what he is doing here otherwise, this seems like a well thought out way to shorten the bed and Im on my toes to see how he does the back part of the bed.

[Vintage Windmills]

Originally Posted by 29od1

Any of you certified welders know what the reduction in material allowables is due to welding? We could do a quick axial and bending calculation on the frame and see if it's anywhere close to Fty. My guess is that with a good weld and a 3 ton load at the rear bumper, it should be no problem with a C20 frame.

At least the analytic calculations would stop the conjecture whether it will fail or not.

Probably a fatigue crack propagation problem, which occurs at less than yield. If we could find guidance on reduction allowances, just multiply the allowable stress by the x sectional area of the C20 frame and compare to same calculation with a stock swb C10 frame and no allowance.

[tommys72]

I'm wondering why this guy is catching so much trouble here? I've welded two things in my life, so would I try this, no. Dude has been welding 30 years, and by reading, does it everyday. I'm sure he wouldn't do something that isn't going to work. Has he told anyone to do it his way? He made a build thread for us to look at, not junk up with a bunch of middle school crap. Send him a pm if you want to tell him his way won't work or whatever. Maybe it's because he hasn't built a truck on here yet. Not that I want to drag others in, but what if superflysteiny did this? I almost bet no one would say a word about it.

*Eric, I love reading your builds. You're a household name around here. Just used you as a point guess you could say.

Now, I'd love to see these besides, please continue sir.

Tom

[leftybass209]

I'm not sure this thread will last much longer if it becomes a massive critique about what one man decides to do with his property. I for one would like to see it continue on the right track.... perhaps with pictures of shortened bed sides

[leddzepp]

Very different approach and I am enjoying following along with the OP as he goes.

I don't want to lock the thread either

[treveiger]

Great thread. Here's the thing if your a experienced welder and you feel comfortable with this then do it, but if you haven't welded much and are going to attempt any structural changes to the frame then by all means use the plates. Or better yet have a professional do it. I'm sure the OP will check the truck regularly and I'm sure the other guy just wanted to warn the people thinking to attempt this. The site is great for ideas and help but always research a lot before attempting anything yourself.

[hamjet]

Very nice work. Wish I could do that well. Very talented and skilled. Ya just can't knock it....

[jjzepplin]

I like it! I want to see the bed work. PLEASE continue!!!
Are you sure you're not a magician? How do you get that metal to bend like that? Mine would look like Hail hit it.

[EARNHARDT#3]

I can't remember what show it was (modern marvels or how it's made...one of those) but they showed a HUGE earth mover dump truck. Like big enough to fit 40 pickups in its bed. The frame was welded together from the factory. Each joint had 100's of welds that made up a huge gap (like a foot wide beveled gap). Then when it was done they used the ultrasound thing to check it just like the OP was talking about. If they can use that technique for that big monster it sure as hell is good enough for a C20.

[Dustmaker65]

Very Nice Tony!

Wife made a great decision

[WarMonger]

Build is going good. You are a good welder/fabricator. Keep us posted on the bed.

[Ft.ValloniaStreaker]

If you guys really need something to worry about...worry about all the guys buying these trucks hacked up, rotted out and painted up like a show truck. Some people know what there doing....some think they do, and even their better off than the next bunch...the clueless with cash. That's the people i worry about driving beside me on the road. Carry on Sir!.....as will the rest of us.

[catch2otwo]

imo, there is nothing wrong with all the critiquing. If not one bothered to question, how would you learn anything. Never good to just blindly follow, no matter how much experience the guy has.

Good thread, looking forward to more progress.

[msgross]

nice work...