LWB to SWB Questions?

[LT1]

Hello to everyone on this killer forum!!!!! I'm very happy to be a member of such an informative forum. This is my first post, and surely won't be my last, as I have an extensive build on the way. I will be starting a new thread in the Build section shortly. I'm trying to gather as much info on converting my LWB frame to a SWB frame. All my lowering components will be purchased from Porterbuiltstreetrods. From what I have gathered so far I like the way that Rokcrln has shortened his frame the most as it seems to be an easier cutting method. Does anyone have opinions on this method vs. how others have performed this?

[LockDoc]

-
to the board from the Corn State. I used efabman's method that is in the FAQ forum. I had good luck with it and am thinking about doing another one the same way.

LockDoc

[leddzepp]

Welcome to the forum! If you can find a SWB frame, that will make your project much easier. Good luck!

[jabraham17]

I am following the method right now on my 67. So far I have the rear section done and I am waiting for time to get to the front. My advice is, TAKE YOUR TIME MEASURING it will go a long ways when it comes to welding it back together. Going by Rokcrln's measurements vs. pictures, I think that his placement of the front cut does not match his statement. He says 8 3/4" back from the stake pocket but it looks more like 4". I will find out soon. Good luck!

[N2TRUX]

Have you read this- LINK

[slicks garage]

I didn't look at that method. But I have looked at other posts. I spoke with a long time good friend who is second generation in welding and fab. Their living is made by stretching and shortening HD over-the-road, and service trucks. Dumps and Farming.
Don't get tricky with stupid cuts. Just cut it 90 degrees across the frame and but weld with a proper fish plate backing it up. If the weld is the weak link, why does everyone try to get tricky and make for a longer weld? Slicing at 45 degrees creates a sheer condition. Slicing along the middle of the frame to create a step??? I guess some just think if they have more welding it will be stronger.......
I know how my frame will be cut and finished, and I have witnessed my friends work hauling Heavy Duty for over 25 years now......
Just my (and his) two cents........... Greg

[AusTx68]

Originally Posted by leddzepp

Welcome to the forum! If you can find a SWB frame, that will make your project much easier. Good luck!

Big +1 that! SWB frames are easy to find. I made the swap myself using the same year short frame off a stepside. Pics are on my bloglink.

[LockDoc]

Originally Posted by slicks garage

I didn't look at that method. But I have looked at other posts. I spoke with a long time good friend who is second generation in welding and fab. Their living is made by stretching and shortening HD over-the-road, and service trucks. Dumps and Farming.
Don't get tricky with stupid cuts. Just cut it 90 degrees across the frame and but weld with a proper fish plate backing it up. If the weld is the weak link, why does everyone try to get tricky and make for a longer weld? Slicing at 45 degrees creates a sheer condition. Slicing along the middle of the frame to create a step??? I guess some just think if they have more welding it will be stronger.......
I know how my frame will be cut and finished, and I have witnessed my friends work hauling Heavy Duty for over 25 years now......
Just my (and his) two cents........... Greg

First off, I don't see where anyone said the weld is the weak link, and I don't think the "stupid" remark was necessary. Just because everyone doesn't do it the way you think it should be done doesn't mean they are stupid in the way they cut theirs.. By the way, 90 degrees is the last way I would ever cut any frame of mine. If I'm stupid because of that so be it but I don't think that is your call...

LockDoc
.

[LT1]

Thanks for all the information to all that replied!! Another concern I have that wasn't mentioned is making sure everything lines up after the procedure. I plan on using Porterbuilt lowered trailing arms with a step notch to be able to lay frame. By using efabman's measurements will this make the frame the same length as an original SWB frame? I've been reading 68 short steps Incredible Hulk build and plan on trying to duplicate just about everything he's done. Very AWESOME build by the way.

[echo72]

If I was going to use precision Porterbuilt parts, I would just find me a SWB frame. Just my opinion.

[pitbull784]

cutting a frame at the 90 degrees could cause a sheer conditon just as easy as a 45 degree cut. a step cut does not and is easier to line up level and square

[pat 70/71]

My frame is cut@90 with frame stiffeners from early classic worked great, make sure your numbers are right on the money. and there wont be a problem take the time !! lay it out & do it!! not a pro, its just fun for me. have fun!! P. S. I would do it again tomorrow in a heart beat. Pat

[Dieselwrencher]

Ok, for these guys claiming that cutting a frame at 45* or 90* will cause a shear condition, PROVE IT! I used to work in a heavy truck frame shop. All the cement trucks we lengthened used the 45* splice method and had the main frame and usually 2 sleeves in each frame rail. All the over the road tractors used a straight butt, and one cold rolled steel sleeve in each rail. If the metal is prepped properly, the weld is done properly, and if it is reinforced properly you will not have this problem. You would have to place one heck of a force on one of these light duty pick up frames to get the frame to shear like claimed. Personally I prefer the straight cut when I do my personal projects, but you could do it either way.

[slicks garage]

Okay, I don't claim to be a pro welder. But, if someone offers me advise, and they are in the business, I'll listen. And when they tell me to avoid the "stupid" cuts, I gotta think, hey, maybe they know what they are saying. Compound that with what they have going down the road, at 80K pounds, I'll listen............
If, (and I mean if) the weld is not good, then you think the parent metal is the problem? Didn't think so. So, let's assume the weld is not correct. Then if you make a longer weld, is it going to magically get better? So why make a longer weld. The main thing is as suggested. Proper conditioning, and backing plate preparation and additions. So with the proper "good" welds, a longer weld will hold. But, why all the extra work?
One thing is for sure, the step cut will have poor penetration on the lower portion, if the frame is not stood up on it's side and a flat horizontal weld is performed. And if the cut is not correct, then how is it going to come together straighter then the 90 degree cut? You guys better start studying your welding manuals.
Point being, 1/2 ton crusier pickups like we build, probably will get through their next life span, without an issue.
Dieselwrench....... I've never seen a "cement mixer" truck before. It is concrete. Cement is the powder that glues it together.

[slicks garage]

Oh, I forgot.

"Mamma says, stupid is, as stupid does." Forest Gump.

So, I listen to people with vast experience. A wise man once told me... God gave you two ears, and one mouth.

[LT1]

So would this be the best method?
http://67-72chevytrucks.com/vboard/s...223158&page=12

[ace of shades]

Every truck I know of *in this town* has been cut at a 45. there is one odd duck running around that has been "step cut". They do that because you have a longer, stronger weld, it actually looks cleaner when done, and from what I understand is easier to fit up.

What ever your method is, make damn sure its a good clean weld, and remember, you can never gusset too much