In regards to the proper material to use... So my neighbor installs commercial fire sprinkler systems, he brought me some s**** pipes for use on my "C" notches... The 4" is sch 10. (Kinda thin wall) and some 6" sch 40 (kinda thick wall) would either of thes be appropriate for my notches? I also got some remnants from the steel store of 3/16" plate for boxing the frame. Any and all thoughts are welcome. Is the 3/16" too thick? Is the 6" sch 40 too big? Is the 4" sch 10 too thin? P.S. the axle is 3" (56 olds) & all this is going on a 51 Studebaker pickup.
If you are building a real C notch as in notching your existing frame rail the 6" will work like a champ. Don't forget to gusset it as well.
The ch***is is almost certain to be 1/8th (10 gauge) so it's best to use matching material. I personally don't like the idea of c notching, I feel that it weakens the ch***is but I know it has been done many times. Here is a link to what I did instead, http://www.jalopyjournal.com/forum/showthread.php?t=596032&page=5 David
As PNB'r said you need to gusset or reinforce that type of C notch with added material above the notch. If you just notch it and box it there is a good chance you have created a weak spot that will eventually crack or break. Scroll down on this chart and it gives the wall thickness for pipe at different sizes and schedules http://academic.evergreen.edu/projects/biophysics/technotes/fabric/pipe.htm
Thank you all very much for your timely responses! I kinda figured on the bigger notch but was worried about it being too big but gusseting it like ya'll said makes the most sense...I'll just gusset it in few times before I box it in! Thank you again!
I have a picture on the way. ***uming a 4" frame and the 6" tube. The C notch will actually strengthen the frame if it is done correctly.
Remember, if you're running leaf springs the differential moves rearward with suspension travel as the leafs flatten. You must make allowances for this movement when notching or the differential will make contact with the back of your notches. If you're running arms or links the notch goes directly above the rear end.
Here is that pic. This is allowing for a 4" frame and a 6" pipe. But it is not to scale. The arch cam be moved lower in the frame as is required. One thing that should be taken into accout also is that all plate etc should be fit up corner to corner and the weld should completely fill the fillet area. So 1/8 plate to 1/8 plate for example will have an eight inch weld, or it will be approx. 1/8" through the throat of the weld.
The wife and kids gave me the day to work in the garage so I got to work... [/IMG] [/IMG] [/IMG] [/IMG] Welded inside and out.
An extra boxing plate midway in the frame rail with a regular boxing plate on the inside surface should help reduce (eliminate?) any weakness the notch has induced.
Ok, I'll double up on the boxing material right around the notch. Tiny? It's 6" ID and my axle is only 3"....boy, I hope I didn't blow it and make it too small... [/IMG]
I spent some time ****yzing c-notches a few years back. How much strength you really need depends on how the rear suspension is mounted (coil springs, leaf springs, coil overs, etc.) and if your going to install a hitch on the vehicle for hauling, etc. In any event here is a link. I hope it helps. http://67-72chevytrucks.com/vboard/showthread.php?p=4597148
Lakeroadster, I always meant to thank you for doing that research and posting. I just took a while to do it! So thanks, That's way better than just saying "i've done it this way and it didn't break." It should be required reading for anybody contemplating doing a notch. Ralph
Lakeroadster I did some reading on your link and I appreciate your input and the work you did in ****yzing notches. Lots of great info! Here is what I came up with to strengthen my notches... A pic of the first one welded to the outside of my 2" frame... [/IMG] I think if I do this inside and outside of each frame rail and then box it in then I will actually be making the frame stronger than it has ever been in the last 62 years... What do you think? [/IMG] Stupid cell phone pics... Shoulda got the REAL camera out...
I think adding the half circle and then boxing the open side is enough. I ran a generic model where the notch cuts about half way through the frame height and found: Notch with Reinforcing half circle = about a 50% reduction over stock (obviously, but proves the model valididty) Notch with Reinforcing half circle and a boxing plate on open side of frame = 13% increase over stock As a sanity check I ran a model with no notch but boxed the frame. It is 2.17 times stronger than stock which would seem to prove the model as somewhat accurate. But, as previously stated: The information posted here is for reference only. Results will vary based on actual dimensions, materials used and the quality of the implementation and fabrication.
LAKEROADSTER, I tip my hat to you, thank you for running the numbers for me. It will help me sleep better at nite. Kinda makes me wish I hadn't changed majors in college from engineering to business. I've always marveled at engineering and physics.
Glad I could help fellas and thank's for the accolades. One more suggestion. When you add the boxing plate bevel the edge and fit it about 3/8" inside the frame, then use a groove and fillet weld to attach it to the frame.
Notched the rear of my 52 ford with 4" 3/16 wall tube and welded a nut to the inside for a bump stop. Got 3 more inches of suspension travel, no gussets
Wow so cool to find this on here must have been searching the wrong topic, anyhow was wondering why screen name Lakesroadster was on the chevy truck site and newest post was 2011. I've spent a few days trying to figure out if I should c notch my 69 f-100 I only have 2" of suspension travel after axle flip. This same c notch would give me about 1 1/2 to 2" more with a small bump stop 11/16" I had read through the posts on the chevy site for about 3 hrs following to the consolidated link you posted above and at that point I was ready to give up on a c notch as it seemed to compromise strength too much. Found this thread by accident when I did an image search and saw the pic of the reinforcing circle. So did I read it correct? boxing with the reinforcing circle actually increased strength, thought the only way would be to build a bridge on top and I'd be through the bed floor to do that. Would this add any strength Sorry to hijack thread
Jcox68rt and I exchanged some information via PM's. Since he has a '67 Chevy C10 his frame is essentially the same as my '65 that I did the original ****ysis on. I therefore felt comfortable running the ****ysis for him based on the actually parts he was using. I am not familiar with a 69 F100, frame dimensions and thickness, suspension type, etc. As the old saying goes "Your Results May Vary".
No problem for now I think I'll wait on the c notch and go with an AOL to restore suspension travel. Then this winter i'll raise the bed floor and do a step notch with a 4 link. Thanks for all the research and testing you did. The chevys have so much more suspension and aftermarket available I almost went with a truck arm style.
The key point to be careful of is that your frame is now reduced height in the notch area. Height is what really give the strength in bending. The frame has tension on the bottom and compression on the top, with a neutral point in the center with no stress, ***uming leaf springs. By putting the notch in, you have increased the stress level as it has to be held by less material and distance from center neutral point. A gusset on the top, higher than the frame is best, but not always possible. So boxing the inside is a reasonable solution to increase the material in that area of the notch.
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