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H3 Heavy Duty Skid Plate

Schwarttzy

Sponsor
Messages
1,348
Location
Rockford IL
I think with some additional gusseting/ bracing that guard could survive any beating you could give it. I think you'd have to figure out some additional attachment points with M10 bolts and toss those M8's....there's your opening, Schwarttzy....

OOO, Then I can keep the factory skid styling.
 

Schwarttzy

Sponsor
Messages
1,348
Location
Rockford IL
Updated the thread title to reflect the current direction, I haven't heard from my laser guy in while and will be calling him Monday, but basically this thread isn't dead and I still want to make this happen.
 

Portager

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Messages
1,506
Location
Silverado
I'm not convinced that Aluminum is a good choice for a skid plate. Aluminum is soft and the surface has a tendency to gouge and tear. I think it would be fine for skidding over snow, but not very good for skidding over rocks.

I would recommend the 6,000 series aluminum for corrosion resistance in a salt spray environment. 6061 would be the best choice due to its yield strength of 40,000 psi and an ultimate strength of 45,000 psi. 6063 would be a bad choice since it has a yield strength of only 21,000 psi (but it looks nice).

You will need galvanic isolation to prevent corrosion where the aluminum contacts the steel frame.

Another factor to consider is the modulus of elasticity of aluminum is 1/3rd that of steel, so for the same cross section the aluminum will bend 3 times as much under a load. This can be both good and bad depending on your design.

I have seen H3's and an H3T (mine) high centered on their UCP with almost no weight on the wheels, so I would design the UCP to carry the full weight of the vehicle without yielding. My UCP is developing a curvature which I'll have to rectify someday.

If you want to do a lattice type design like the OEM UCP, which I think would be better for hot operating conditions. I would recommend ASTM A513 also know as DOM (drawn over mandrel) steel. DOM is only available in round tube, but it has a yield strength of 72,000 psi and an ultimate strength of 87,000 psi.
 

Schwarttzy

Sponsor
Messages
1,348
Location
Rockford IL
Thanks for the input Portager, can really tell you know what your talking about.

The end goal will be that these skids plates can holding the entire weight of the vehicle, I'm hoping a half inch worth of Aluminum will get the job done. I not sure with the grade of Aluminum yet because I haven't heard from my laser guy. I also understand your concern about over heating and it will be something I watch out for and may influence the design.

However if aluminum fails I will be going to 3/8 steel because I'm really trying to avoid the lattice design, but who know that maybe the only effective design when all thing are considered.
 

justin94tt

Well-Known Member
Messages
169
Location
Springfield VA
My personal opinion is that it should be made of steel, because of the softness of aluminum. Crashing down on rocks it won't take long to gouge aluminum up. I know that the DOI company was able to make their design with 3/16 steel and it seems pretty sufficient as I know one person that I wheel with has it.
 

Schwarttzy

Sponsor
Messages
1,348
Location
Rockford IL
Guys hold you horses on the whole aluminum debate, it will be literally nothing for me to switch over to steel or any other material.

Actually... come to think of it... when I finish the design I could easily let you guys choose the material it's made out of.
 

ArtHummer

Well-Known Member
Messages
1,220
Location
Gaithersburg/MD
Of course a plain sheet of steel will be stronger the plain sheet of aluminum. But clever structurally designed aluminum part can be strong enough... Can't wait to see what you will come up with
 

rsc

Well-Known Member
Messages
1,087
Location
Tulsa
I personally would like to see your design made out of 3/16" steel (not stainless). Preferably 1/4" thick with 1" wide laser cut slots from front to back like those welded on plates for the stock UCP. THAT is what I would spend my money on. The extra 1/16" should only add about 20 lbs to the weight of the skids, around 110 lbs total?

weight= thickness x L x W x .284
 

rsc

Well-Known Member
Messages
1,087
Location
Tulsa
I don't think painting and rust prevention is going to be a problem, however I do worry about the bend/yield strength of aluminum and multiple hit deformations over time, even at 1/2" thick. Aluminum is roughly 4/5ths the strength of steel and 3 times lighter but I don't think its ductile properties are the best for this application. After all, carbon fiber composite is 5 or 6 times stronger than steel and feather light in comparison, but it would not be a good material for a bash plate.

What do you calculate the force of a hit to the skid plate to be? Lets say a 6,000lb vehicle dropped from 18" on a 3 square inch contact surface? Will aluminum hold up to repeated hits without cracking? How much will the aluminum bend before it doesn't spring back any more and dents versus steel? Just throwing it out for thought.
 

is350

Well-Known Member
Messages
202
Location
fallbrook, Ca
I'm just curious has anybody ever used UHMW for skid plate material on jeeps or trucks? I know its used pretty often in the UTV world
 

rsc

Well-Known Member
Messages
1,087
Location
Tulsa
I know some Jeep guys running that on their skid plates for a smoother slide over rocks, but they still have steel under it for strength.
 

Expendable

Well-Known Member
Messages
1,025
Location
Burbank, CA
not looking for an argument. but there is a reason why H1 owners swap out their factory Aluminum rockers for factory and or aftermarket Steel rockers.
 

telemike

Hummer Enthusiast
Messages
466
Location
Greensboro, NC
How long? I am itching to buy some UCP after Christmas but I can wait until March. I was going to get the GM OEM but I am intrigued at a beefier solution. I would suggest laser cutting in some slots for drainage
 

Expendable

Well-Known Member
Messages
1,025
Location
Burbank, CA
Fine, Fine, I'll be moving the design to quarter inch steel in light of all this opposition.

I was in no way trying to change your mind. I'm just bringing up years of experience that H1 owners have had.

I do not have a H3. most experience I have with them is driving two 06s when my mom and brother each had one years back. and you can't directly compare a H1 and a H3. but I figure you can learn from their experiences.
 

Schwarttzy

Sponsor
Messages
1,348
Location
Rockford IL
Great news guys!

I received a phone call today telling me that my two mock-up quarter inch skid plates have finally been made and that they are ready for pick-up. I haven't figured out the bolt hole locations quite yet... I'll probably use the factory locations, but we will see. I shouldn't have much of a problem meeting my price goal of $300 + Shipping for these powder-coated black with all the hardware necessary.

I hope to do a big batch of these skid plates the first time around and would be happy to pass the saving on to you. How much that is... I'm not sure, but it is related to how many people we can get in on this run.

I hope to have photos of these skid plates tomorrow.
 

Portager

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Messages
1,506
Location
Silverado
I am interested, but I'm waiting to see the results of the prototype installation and trail testing.

Also, when you get a chance if you could weigh them.

Sent from my Galaxy Nexus using Tapatalk 2
 
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