Pipe Notch

[sailed2japan]

I also definately learned something from ths thread. I guess this is another situation were logical reasoning and engineering bump heads! I'm just curious about how crunch the numbers on a boxed section of frame. This info will come in very handy in the near future.

[DWright]

All of this is exactly why i post here. I came to this site to look for fresh ideas and information and thats exactly what i get, and am very appreciative of that. I have never been to any other forum where the people are so helpful and respectful to each other; i love it! This site is what has kept me moving on my project, and i thank yall for that.

[sailed2japan]

[aerotruk63]

To bridge the structure where the weaken point exisits could restore or even improve the rating on the frame but who wants a dinner triangle hanging under the truck? LOL

[protrash64]

Originally Posted by lakeroadster

As for the bolt holes, they don't effect the strength very much as long as they are spaced away from each other.

I guess to make a more extreme example, using the 4.75'' frame rail from page 1 (d).....what if, centered on the frame rail, one was to holesaw a 3'' hole thru the frame. What does this do?

My father was an engineer at Caterpillar for 40+ years so I'm used to physics, equations, and math blowing holes in my 'common sense'.

[daverod]

That CAD stuff is cool. I don't even want to know what it says about this. Well I do kinda. Maybe it's better not to know. I'll just drive slow most the time. Not

[sailed2japan]

Man I love this stuff!!

Am I reading this wrong or is the c-notched frameW/ box and repad showing to be stronger than stock? Also wondering how well it would work if you were you put a second arch inside the frame rail? Maybe using 6" pipe? And am I interpreting the procedure correctly where the re-pad is actually replacing part of the frame?

I personally appreciate all the time you've spent on this. It's been a real eye opener for me and will help me build a better truck.

[aggie91]

This is an interesting discussion.

Could you post the section modulus for a square tube shape? Like you did above for the C channel.

[DWright]

would something like what i've drawn here on my work table restore some of the lost strength? its simply the remainder of 1/4'' wall pipe with 3/16" plate on both sides.

[SCOTI]

I sat down tonight to try & decipher my set-ups values but seemed to be getting lost somewhere because of the notched area. Man, I wish I was better @ math calculations.

I'm tired so I'll try again tomorrow ....

[sailed2japan]

John, I think you opened pandora's box of frame mod calculations!

[aggie91]

John, Thanks for the link. I can use that...

[sailed2japan]

Fabrication would be a hight, but the way I see in is:
1. weld the 6" pipe to the box
2. weld the 6" pipe to the re-pad
3. weld the 4" pipe to the box and re-pad
4. put it all in place and weld it to the frame

This process would allow you to back weld the 6" pipe. If you wanted to be able to back weld the 4" pipe instead all you would have to do is put that one in first. I couldn't think of a process to et both of hem back welded.

[DWright]

is this workable? sorry its so crude. and yes, the extra 1/4'' wall pipe is used above the frame and plated on both sides with 3/16" steel.

[protrash64]

We may have to start paying consultation fees soon!!!

[sailed2japan]

I think (yes, I know it's dangerous) that if you were going to do a notch that big you would be better off just doing a step notch.

[DWright]

the pipe was 6" od. i wasnt too concerned with the bed floor as mine is currently a sheet of plywood. i was thinking of raising it about 2" to clear the diff. when aired out anyway. what kind of steel do you recomend be welded to the top of the frame? i was only asking about the remainder of the pipe because i already had it and hate wasted steel.

[SCOTI]

Originally Posted by sailed2japan

I think (yes, I know it's dangerous) that if you were going to do a notch that big you would be better off just doing a step notch.

x2.

[SCOTI]

The issue w/mine will be there's not much room to plate the sides of the frame between the c-notch, Panhard bar c.member, & shock c.member. I'm trying to come up w/something that can be welded to the top of the frame rail & add strength.

Solid bar,thicker c-channel, what do you guys think?

[DWright]

thanks for the work Lakeroadster. i notched the frame lastnight and installed the 6" pipe notch. i'm definitely gonna add a piece of heavy wall 2x4 steel to the top of my frame.

[SCOTI]

Originally Posted by lakeroadster

Shoot me a picture with some dimensions of what clearances you have and I can give it a shot if you like.

You've got mail.

[SCOTI]

Originally Posted by lakeroadster

Scoti,

How is you overhead welding abilities? If you were to add a piece of 1/2" solid round bar to the notch as shown in the attachment and then grind the welds such that they feather into the notch it helps a lot. Plus I would suggest that you grind a radius on the notched edges as shown in the attachment, that also helps. As a rule, radius edges when you can, that always helps reduce stresses.

The upper truss is 10-1/2" overall length, is boxed in, made from 3/16" plate, and ends are angled 45 degrees.

I hope this helps.

It's a frame on a quasi chassis table/jig. I suck @ overhead stuff but flipping the frame is very do-able . To make sure we're on the same page, what height did you establish on the truss?

[jonathan-m]

Originally Posted by lakeroadster

1-1/2" high on the upper truss... see attached.

Be sure and let me know how this works out for ya.

I can't even begin to tell you how interesting this whole discussion has been. Thank you for sharing your knowledge with us.

[SCOTI]

Originally Posted by lakeroadster

1-1/2" high on the upper truss... see attached.

Be sure and let me know how this works out for ya.

Dang..... I'm going to owe you BIG TIME for such professional advisement .

Here's what I'm thinking.... Looking @ the contours of the frame, simply attaching a generic piece of steel 'tube' to the top of the rail will require considerable chopping of the material & will look like an after-thought (would work great on a nice straight frame though).

In keeping w/the concept, I still have the extra frame that I originally intended to use for this build (but the frame was bent). I'm thinking I'll cut that proposed area from the extra frame & weld it to the compromised section of this frame adding an additional ~3" of height in that area & add the solid .500" piece @ the rear portion of the notch.

I'll add three 90° 'L' shaped pieces of angle under the 'new' section that will tie the top of the current frame to the side & top of the new section. I'll space the three brackets equally (one @ each end & one in the middle). The end pieces will be where I'll start the 45° transitions that will tie the old & new @ the ends of the 'truss' & I'll box the back side similar to what I did for the current c-notched area.

This should leave the frame visually consistent (like it was planned all along ) while reinforcing the area I didn't think through before commencement of fabrication.

[SCOTI]

Originally Posted by lakeroadster

I got ya, the tops of these frames are not straight, good thinking on using the other frame for the additional truss.

However I don't know that I would use an additional 3" to the frame height. If you were to maybe cut the frame section such that you end up with the 1-1/2" to 2" of additional height that should be adequate and it would still follow the contour of the frame. And for the ends I would angle them at 45 degrees and not use structural angle. Remember, abrupt changes mean stress risers. Try to make it flow without any hickups, if that makes sense. Smoother be betta.

I might have not been clear enough in my description. The angle pieces would be underneath the outer structure simply to assist tying the 2 sections together; the 'ends' of the truss would be 45° angled from new to old frame sections.