Pipe Notch

[protrash64]

Ok, thanks John.........that's cool!! Now my question is what is the difference from boxing to '' heavy structural steel members that are added to the existing frame rail.''?

Isnt that just the same as boxing on the outside of the frame? And, do the bolt holes reduce the section modulus of the frame?

[protrash64]

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

[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

[darkhorse970]

Originally Posted by lakeroadster

Yep, from a "calculation standpoint" adding the structural steel member is about the same as welding in a boxing plate. Most of the bolt on kits use a steel plate that is considerably thicker than the stock truck frame thickness. That helps but I still would like to run the numbers on one of the kits to see if it is as strong as the original uncut frame when all is said and done.

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

I took a little time this morning and made a solid model using Inventor Cad software. (See attachments below)

First I made a model of a stock frame rail.

Second a model of a c-notched rail using 4 inch pipe (0.237 wall) as the notch. This configuration is about 75% weeker than the stock frame.

Third was the c-notch with a 1/4" thick boxing plate. This configuration is about 25% weeker than the stock frame.

Using FEA is more realistic than the simple channel and tube calculations that were discussed in the previous posts because it looks at how all the parts work together as a system. And the cool thing about this type of analysis is it gives you a warm fuzzy feeling about how different modifications effect the strength of a part.

Kind of neat, don't ya think?

This is very nteresting reading...

John, did you run the numbers on an "off the shelf notch"? (I wanted to attach a pic of the one I have from Early Classic Enterprises, but can't find it on their site now) I'm very curious to see how this stacks up the to other designs shown here.

I have not installed it because I decided that it probably wasn't necessary on my '63. I was thinking about using it on my '68, but I'm not sure if thats a good idea or not now.