Pro Mo's adventure in rust and ruin. (A build thread)

Projectile Motion · Post by **Projectile Motion** » Fri Aug 10, 2007 12:08 pm

Yea it is a pretty cool trick that came out of the aircraft industry. If you follow the link at the bottom of the page then go to the link called "punching holes for strength" there is good info on the advantages of dimpled plate.

SpazMO · Post by **SpazMO** » Tue Aug 14, 2007 1:27 pm

One doesn't necessarily achieve lower stress by simply inserting a hole into a member. Stress flows need to be modified correctly for the technique to work. Flaring a hole helps this, insofar as it moderates the effect of the "edge" of the hole, which is in fact a stress concentration point (thereby requiring less precision of hole placement and size). It also adds a second dimension to the plate, preventing buckling.

I wrote a quick memo on it for a program I had to develop in school, hopefully it captures what I mean without boring anyone to death.
http://infohost.nmt.edu/~rslingsb/NMT/M ... AB%234.doc

Post by **Leatherneck** » Tue Aug 14, 2007 1:30 pm

SpazMo, you are one of those highly technical guys aren't ya? Going to have to watch you

, I can see that now.

SpazMO · Post by **SpazMO** » Tue Aug 14, 2007 1:52 pm

heh- I get paid to do that stuff, so I figger if I can lend a little of what I know to others, might help.

Don't worry too much tho- my dubb doesn't reflect any technical anything

Real point of the story is that those dimple dies look really cool.

rickosuave1987 · Post by **rickosuave1987** » Wed Sep 19, 2007 4:34 pm

Any more updates to your build recently??

and you still coming to El Mirage?

Projectile Motion · Post by **Projectile Motion** » Wed Sep 19, 2007 5:17 pm

No, the car still looks like the last photo. Work has been super busy lately which naturally slows progress. The good thing is more work means more money so that will help! I might go buy the shocks for the front end this weekend so I can get those mounted. I still need a fuel cell and seats to finish up the interior. I really need to start thinking about a motor now too. The list goes on and on

El Mirage is now iffy for me. I am having to work a lot of Saturdays so I will not know until about the Wednesday before.

rexr · Post by **rexr** » Wed Sep 19, 2007 7:19 pm

Projectile Motion wrote:The good thing is more work means more money so that will help!

At least you are getting some extra peyote for the extra work.. I haven't been paid OT for so long I don't remember what extra money is... But I know what you mean.. I need to retire so I can have time to build my car...

Projectile Motion · Post by **Projectile Motion** » Sun Oct 28, 2007 1:42 pm

Well not a huge update (but a lot of pics for you) but some progress on the car. I was working at a school in Rancho Bernardo this last week so needless to say work was canceled. I made the best of my time off and got some work done on the bug. Some of the new work I actually did a few weeks ago but figured it was not enough to post about.
First is the plate work to finish up the rear shock mounts.

Here are the front shock mounts. Still need to finish welding them into the beam but I need to disassemble it first to take the bushings out.

Here is a picture that I sort of screwed up but I thought it ended up looking cool. Front shock mounts.

Here is the dash. The center part will have a removable aluminum panel with all the gauges and switches. I welded a piece of steel from the top bar to underneath the windshield frame. I have very little sheet metal experience so with the arc of the car and the strait tube it was tricky but I am happy with how it turned out. The welds will be grind down and sanded out as smooth as possible. Steering is done for now too. (Power steering will go in a little later. I have better places I could spend the money right now)

I guess anyone who has done tube work can apreciate a good tube junction. They do not always go this smooth so I want to brag a bit.

That is about it for now. I am really close to having a roller. Actually all I need is lug nuts, two more wheels and 8 springs and she will be rolling! Unfortunately that adds up pretty quick to a lot of money.

Post by **Leatherneck** » Sun Oct 28, 2007 6:31 pm

Sweet work, killer welds, I am jealous. Keep em coming.

Super "B" · Post by **Super "B"** » Sun Oct 28, 2007 7:30 pm

Looks Awesome...Yours skills look top notch..either that or that is some real fancy Photography work....One Question what is the measurement on the width of your beam? I just picked up one from a local guy and it measures 43 1/2". I think I might need to cut it down a bit. so it can match up better with my 3 x 3 rear arms.

Projectile Motion · Post by **Projectile Motion** » Sun Oct 28, 2007 8:00 pm

The beam is 40" end to end. I sort of wish I had gone with an 8" over beam (42") to match up with the 4x5s but the 6" over is good for 3x3s. I would cut the beam down to 40" if I where you unless you want it that wide in the front.

runslikeapenguin · Post by **runslikeapenguin** » Mon Oct 29, 2007 4:29 pm

if your going to continue tack welding your cage make sure you do three things
1. turn the welder up to make sure you burn in stronger
2. over lap the welds more, you need to only show a quarter to half of the first tack, you dont want that little start and stop pock marks.
3. make sure that after you stop the weld and move and start again that the first weld is still red hot, to get as much continual penetration as possible.

Projectile Motion · Post by **Projectile Motion** » Mon Oct 29, 2007 5:55 pm

Thanks for the advise rlap but I must say that I have a hard time taking advise from someone who is too chicken to post pictures of their own work. I know you are building this super secret class 5 (But you're still too cheap to buy a freaking $30 rule book

) but I call bull. You just won't post pictures because you are afraid someone will tell you how you are f-ing up. I took welding classes probably before you had your times tables memorized and have worked with a lot of people in the industry. I have built offroad cars before (including suspension) and have NEVER had a weld fail. Have you even been at this long enough to truly test any of your work? Not that I need to explain myself to you but since you chimed in with your expert opinion (note sarcasm) The plate work shown was "trigger welded" as are some of the hard to reach areas in the cage work. While it is "faking it" to some extent the areas I chose to go about this method allow for it. Not only that but I learned the procedure for this method in a class and am fully aware how to go about it. These are tricks I learned from people who's opinion is very well respected in the offroad world.
By the way "Tacking" is the first few beads laid down to get pieces to stick.

By no means do I consider myself anywhere near professional level of fabrication but for comparison here is the shock mounts on a Penhall car. Do you have advise for him too

DesertGuy · Post by **DesertGuy** » Mon Oct 29, 2007 6:04 pm

Holy Crud... That will never hold

Yep, I think ProMo just needs to gut the whole thing and start over...

Very nice build, BTW

Post by **david58** » Mon Oct 29, 2007 6:14 pm

My Mother used to knit like that.