'72 K5 - Greg's @MightAsWellK5 Build

[BigBen]

For what it's worth, these guys are definitely taking you in the right direction! Kyle, it's good to see another on here working in Pro/E and running FEA. The only thing I lack is access to a Faro arm (I work on my own).

I'd have to go back and review my mohr's circle to tell you for sure, but I think you're ok here looking at the simple loading. I believe Mohr's circle comes in more when you have to take several loads and resolve them into pricincple stresses and shear loading to make sure that a part won't fail. (Think tip load on a road sign at the edge and you want to see if it shears off at the base).

I really don't think we need to dig into herzian contact stresses here. That comes in more whith repeated cyclic loading like bearings and gears.

About the only thing might be fatigue, but since we're using steel we should be able to make sure we're covered by a safety factor on the s-n curve. (Fatigue strength is manageable in steel since it levels out over time)
http://en.wikipedia.org/wiki/Fatigue_(material)

Kyle's going to be wathing for that and making sure you don't have any stress concentrations in your design (No sharp corners, nice uniform welds).

other than that, the build is awesome and kyles definitely taking you the right direction.

Kyle, I'm assuming you've got it too, but I've got a my own seat of Mechanica and also can help by running stuff if need be. We could also look at running Greg's design in mechanism and making him a little movie of the motion....


-Ben

 

[Greg72]

I appreciate all of the input.... whenever you guys can provide a formula or two I'm willing to do my own legwork and figure these things out.

It's an unbelievable day outside....47 degrees and SUNNY! After a long, cold winter this feels like summer. I've got both garage doors opened wide and I'm lovin' it. Don't worry, I'm taking photos.... the full update will probably have to wait until tomorrow.

My lunch break is over, I'm heading back outside.

 

[swartlkk]

Yeah, sorry Greg. I was stuck in a class room today learning how to field strip and service our Scott NXG2 4.5kpsi SCBA's and I have been busy with work and other things now that it is decent outside. This next week I won't be able to do much to help out either... We've been socked with trying to clean up orders from the end of last month that are now late.

I have my own copy of Pro/E & Pro/Mechanica although I do not trust Mechanica output for anything other than comparisons. I don't use the numbers for anything. If I really need to run a representative FEA, I use Ansys. But I also have an HP Elitebook from work that has WildFire v2 on it while my personal copy is quite old (2000i^2). I have to transfer stuff over onto my workstation in the basement to run Ansys models though.

I would love to talk the shop guys into scanning in my 2nd K5 frame with the FARO arm. That would definitely be sweet!

 

[Greg72]

2010.03.07 - UPDATE! - RECYCLING AND STAYING GREEN...

First, to let you all know I have finally succeeded in recovering the last of the broken photo links at the beginnning of this thread. The side admin over at NorCalBigDawgs was able to retrieve them from an old archive and send them my way, so next time to go back to Page 1 of this build thread you shouldn't see any more red 'x's...

UPS delivered another heavy and expensive box from Evolution Machine on Friday afternoon.... the medium heims for the upper links!

I put a couple of the original Large heims in the photo to show scale....the mediums almost look "cute" by comparison!

For this weekend, I decided it was time to start dealing with some of my 2x4 lumber crossmembers and replacing them with somthing more substantial...

Since I had never thrown the old rear receiver hitch away, I decided to do the "green" thing and RECYCLE it. Some will remember that was built to fit the old C-channel frame and ended up matching the distortions of that frame.... I think it was about 1/2" wider than it was supposed to be. Fortunately, now that the frame is boxed and narrowed to the correct stock overall width, all I had to do was cut off the excess and build some new end plates.

As I'd done before in the Body Mount #1 position, it was time to sleeve a piece of thick-walled tubing into each of the holes I intended to use. This basically requires me to drill out the existing 3/8" rivet holes to 7/8" so that the sleeves will fit. On each one, I also cut a generous bevel with a countersink bit to give better weld penetration.

Here's the shot before welding... (and my existing lumber crossmember)

Once all the mounting holes were sleeved, welded, ground flush and painted, I was able to install the new "restored" hidden hitch. Based on the way the hitch is now installed and braced I think it's possible to lift the entire weight of the truck by this recovery point if I wanted to...

I had a little bit of time left yesterday so I decided to put the 4L80E into position for fun also. I was curious to know what sort of clearance would exist under the tranny pan for another set of frame-side coverging links (to match the rear design). From the looks of it, there's a pretty good chance I'll be able to fit them in there.

This coming week, I'm dropping off the raw materials with my machinist and he'll start cutting the rear links to length, cutting wrench flats into the ends and doing all the L/R hand threading. That will allow me to drop the "real" parts into this design, and then steal the PVC ones for the front suspension mock-ups.

 

[Chevy305]

wow i think there may be some overkill on that cross member...

 

[supersize75k5]

Go man go

 

[ryoken]

Stoutness......

 

[Dr. Custom Werx]

how long before its on its own weight and you can roll it outside for pictures?

 

[Greg72]

how long before its on its own weight and you can roll it outside for pictures?

June?

• Reassemble portal gears into CNC boxes
• Assemble 8-Lug Conversion Parts
• Cut existing axle housings to proper width
• Cut off old portal mounting plates from 404 housings and weld to new housings
• Buy at least 3 more tires
• Finalize front 4-link setup
• Weld in all suspension crossmembers (F & R)
• Build upper mounts for ORI struts (F & R)
• Order ORI struts.... wait 10 - 12 weeks for delivery

I think that would be a minimum list. That doesn't include axle shafts, steering components or brakes.... just the absolute minimum to make it roll. Actually, I could probably just weld in some lengths of tubing to represent the ORIs so maybe it's not THAT much work? More importantly, there aren't any more huge capital investments required which is a nice change of pace from the last couple months.

 

[Dr. Custom Werx]

June?

• Reassemble portal gears into CNC boxes
• Assemble 8-Lug Conversion Parts
• Cut existing axle housings to proper width
• Cut off old portal mounting plates from 404 housings and weld to new housings
• Buy at least 3 more tires
• Finalize front 4-link setup
• Weld in all suspension crossmembers (F & R)
• Build upper mounts for ORI struts (F & R)
• Order ORI struts.... wait 10 - 12 weeks for delivery

I think that would be a minimum list. That doesn't include axle shafts, steering components or brakes.... just the absolute minimum to make it roll. Actually, I could probably just weld in some lengths of tubing to represent the ORIs so maybe it's not THAT much work? More importantly, there aren't any more huge capital investments required which is a nice change of pace from the last couple months.

sooooo anything else crossed off that list yet?

 

[Greg72]

2010.04.10 - UPDATE! BRACKETS, LINKS AND HEIMS, OH MY!...

I got my heavy-walled DOM back from my machinist friend, and now I'm the owner of some seriously large taps (both left and right thread). It turned out that he doesn't often tap stuff larger than 1" very often so I needed to buy the specialty taps to help him get set up properly.

The links are HEAVY. The lowers are something like 35 - 40Lbs each, so it's not nearly as simple to throw them into position under the truck. In fact, they are so heavy that they kept rotating the axle housing down and knocking my jackstands out of position... after a few episodes of that I had to fabricate a couple small saddles for the jackstands so that they'd hold the axletube tight even with the heavier links pulling on them.

I've been looking cross-eyed at my lower link mounts for a couple of weeks now... I just don't like how they came out and the angularity of the mount to the link itself was kind of wonky, so I decided to change them out for a more traditional setup.

I also started working on my upper link mounts, and as luck would have it, the two sets of brackets ended up overlapping each other. That is actually a plus, since I'll be able to plate them together and put gussets everywhere to add more strength. The upper mount will clearly need more reinforcement.

The upper mount position gives me 10" of vertical separation on the axle side which is great for strength, but my design also requires that the upper link be 1" forward of the axle centerline. This required me to put a slight rake in the upper mount. I think it also makes it look FAST!

Another important attribute of the suspension design is that the upper links are not only parallel to the ground, but also parallel to each other, and 42" apart. This poses a bit of a problem, since the frame is about 8" narrower than that at the front mounting position.

I tried a few different design ideas to build something strong enough, and ultimately ended up with a design that actually ties in to the factory body mount plates at postitions #2 and #3.

This allowed me to get the link out far enough to get it totally parallel. Right now I've got it bolted in temporarily to take a picture, but there will be one more plate on the outside of the heim to create a solid double-shear mount. (The black marker line shows where the final plate will go) Once that's in place, I will be able to plate the entire thing top and bottom and gusset and brace the #2 body mount a bit more.

Even though I hate doing them, I have to admit that I'm getting pretty good at building freehand link tabs and plates. The paper templates get transfered to the steel with a silver Sharpie marker and the plasma cutter can usually get me within about 1/16" of the line.... from there it's just hours and hours with a flap disc dressing the edges until they hit the marks perfectly...

Sorry for the slow progress lately, I've been traveling quite a bit for work and that keeps me from getting into the manspace as often as I'd like.

 

[AJs72K5]

That's a lot more progress than I've made lately. Looks really good Greg.

 

[4X4HIGH]

Greg, that ratchet strap holding the lower link mount in position won't work very long.

 

[sponsoredbydad]

That looks great so far. Everything you fab up is really clean and shows the time spent had much forthought (And I thought my build was complicated.) Altho this is not your 1st go around.

 

[Dr. Custom Werx]

im sure its been thought through but it looks like your upper axle link mounts are going to hit the frame when it articulates. prove me wrong with some pictures....
=]

 

[Greg72]

Greg, that ratchet strap holding the lower link mount in position won't work very long.

I'll tell ya, I got really tired of fighting with that mount! It's been sort of "balanced" on a temporary crossmember there but with the heavy links it kept swiveling and crashing to the floor and trying to knock the axle to the ground. All those blankets and stuff you see are to help protect the heims from the concrete... actually, since they're EVO ends I guess the blankets are protecting the poor concrete from the heims!

Josh,

I'm getting close to the point where I'll have enough links attached that I can cycle the suspension. It's going to be close, there's no doubt about it, but as I'm sure you understand it's a careful balance between getting JUST enough clearance for articulation and keeping enough extra room on the outboard side of the axletube to still place the coilovers and get the wheel assemblies tucked in as tight as possible. I don't want the wheel track to be any wider than necessary.... I hear that local law enforcement can be pretty strict about tire stickout. (I think I'm comfortably below the bumper height limits though).

 

[Dr. Custom Werx]

well the only people that ever get harassed are the ones that are rotted and smashed or drive like ass holes. if it looks nice and shiny you will be free and clear.

 

[Greg72]

2010.04.18 - UPDATE! - I DON'T LIKE IT....

As I kept building along on the upper link mounts, it became increasingly clear that the frame side mount was not heading in a good direction. Each time I made accomodations for the #2 body mount and the cab sheetmetal, the resulting mount was getting weaker and more complex. The bracket was becoming a series of small patch pieces, and the amount of work necessary to reinforce the body mount while still giving access to the bolt and rubber mounts was just getting stupid. It was time to take a step back and get a fresh look at things.

Ultimately, what I really wanted was a mount that didn't have to wrap around other existing stuff. Something that could pick up the heim position and move the loads directly into a beefy mount and the frame itself.


Here's a shot of the bracket as it was evolving and getting notched to clear all the body mounts and bolts...

After a bit of measuring the answer turned out to be pretty simple. I could actually move the body mount position from the outside of the framerail to the inside of the framerail instead... I put an extra mount on the inside and marked it exactly 9.5" away from the original. This gives me a good spot on the tub to come through with a new bolt to hit the new mount. I will have to relocate some a reinforcing tube on the tub, but that should be fairly simple.

Once I checked all the dimensions to make sure that it was going to work, I cut down the body mount and bolted it back to the inside of the framerail. There is plenty of clearance for the lower suspension links to cycle, and now I can completely remove the outer mount bracket.

This will give me a much more direct way to build the mount and support it properly with continuous lengths of steel, instead of dozens of small ones.

 

[sponsoredbydad]

Sometimes just stepping back and taking in the whole picture just seems to work. This is a much better angle of attack. I was checking out that new mount and thinking wow how good those bends were, then I realized that you cut the top off shortened it and slid it back. Do you find yourself dreaming formula's and link movements yet?

 

[4X4HIGH]

Sometimes just stepping back and taking in the whole picture just seems to work. This is a much better angle of attack. I was checking out that new mount and thinking wow how good those bends were, then I realized that you cut the top off shortened it and slid it back. Do you find yourself dreaming formula's and link movements yet?

I think Greg drilled a new mount hole and then cut some length off the end. I doubt he "cut the top off and slid it back".