UHWM skids

[rajincajingt]

ok guys, i need some recomendations, i picked up a super cheap 1/4" thick UHWM "drop" from the local plastic house and its time to get the skid mounted up.

what should i support this with? 1/4" plate all around? or can i get away with a square tube skeleton of sorts.

looking to go all the way from the oil pan to past the drive shaft out put.

[james@bluetorchfab]

we mounted 1/2" uhmw to the bottom of our belly skid with counter sunk cap bolts . it hold pretty good as long as you dont snag a bolt on any rocks.

[Devil Dog]

nice set up there... how thick is that pan? 3/16ths?

i have some 1/2" uhmw i am about to put on for a skid and have been wondering what to back it with... it will be roughly 42" w by 46" long... with it narrow on the 46" side covering the oil pan...

[Jason E]

1/4" is a little thin. you don't have much meat to countersink the bolts. I run 3/4" right to the tube frame no flat plate for backing. if your going to use 1/4" you'll have to back it with a plate for sure.

[james@bluetorchfab]

[quote=Devil Dog;10256944]nice set up there... how thick is that pan? 3/16ths?

its 3/16 with ribs running front to back on the top side for added support.

[HydroDynamic]

With thin material go with a large carriage bolt in a 1/2" diameter the large clamping face will help with pull through on the thin material.

[james@bluetorchfab]

you may have to counter bore the plate and the uhmw to get the tapered shoulder deep enough to tighten up with out it being loose.

[chris demartini]

I'm in the process of collecting material for mine. I'm using 3/4" plastic and backing it with 1/8" aluminum. Plastic and backing thickness depends on the size of the skid and amount of tube support it has.

[smitty66]

I got some thats 1" thick. It will be 24"x 36", will it need any backing? I didnt know people put backing behind it.

[chris demartini]

What are you bolting it to?

[ChiScouter]

Elevator bolts might be another way to bolt it up http://www.fastenal.com/web/products.ex?N=999600009

[rockcity]

Elevator bolts are always a great option but they don't offer much stregth. They are normally used to hold UHMW buckets on a vertical elevator belt. I just don't know how much I'd trust them. I've seen way too many of them break with very little force.

If you do use them, however, get the ones with the "teeth" on the head so that they grip into the UHMW and don't spin on you.

[Madzooki]

I have 1/2" with a 1"x.120" square tube skeleton.

Paul

[swamperford]

I work on a farm and our leg (vertical belt with plastic buckets on it) uses the elevator bolts. As said above the bolts are weak. We replace them all the time and they have a very small load on them. The head of the bolt is thin and I dont feel that they would hold up very well to some punishment.

I would counter sink whatever fastner you would use to reduce any shear load on it. My .02

[Slowrockr]

Originally Posted by smitty66

I got some thats 1" thick. It will be 24"x 36", will it need any backing? I didnt know people put backing behind it.

I ran 3/4 with no backing and no issues. Will be doing the same with my new car.

[bamatj51]

I know this is probably way to light weight for most but Ill throw something out there. Polaris makes some small cup washers that could be used on a skid plate and if its thick enough they can be mounted below flush. They are made to bolt down on the frame. I think this is to let the frame flex some without breaking the plate. I used them on my rzr for my 3/8" thick uhmw skid plate. But the bad part is that they use 1/4" bolts and they are just thin sheet metal. But they could be drilled out some and might be okay for some things since they are tucked up in the skid. Its number 5 on this list. http://partsfinder.onlinemicrofiche....pe=13&A=58&B=9

[Mikkofin]

I used 1/2 inch UHMW in my buggy and it was just thick enough to use the tapered SS bolts, 10mm.
Had it been any thinner, would have created problems.

[Mudinyeri]

I used to make UHMW skids for Polaris RZR's. I used 3/8" UHMW with countersunk flat head hardware like this: http://www.mcmaster.com/#91253a542/=3gdr3e

There is a risk that this type of hardware can pull through the UHMW so I used a higher number of screws that one might normally use. The likelihood of them pulling through is low, however, because the forces applied aren't generally pulling the skid in the right direction.

I would probably use 1/2" UHMW if you expected it to have some structural use over a frame. If you're just skinning an existing metal skid, 3/8" would probably be fine. There's not enough depth in 1/4" to countersink the screws.

If you look closely you can see the mounting holes in this picture.

[bamatj51]

Some people claim that the white is stronger than the black. But I have also read they are the same. Anybody know the truth?

[rajincajingt]

Originally Posted by Jason E

1/4" is a little thin. you don't have much meat to countersink the bolts. I run 3/4" right to the tube frame no flat plate for backing. if your going to use 1/4" you'll have to back it with a plate for sure.

it is a little thin, but this is a 5'x4' drop, it is cheap ($60) a new 4x8 sheet is $280! so i am going to use what i got.

it looks like i need a real plated skid with a good skeleton for support and just use the plastic as a cover.

Originally Posted by HydroDynamic

With thin material go with a large carriage bolt in a 1/2" diameter the large clamping face will help with pull through on the thin material.

i like the carriage bolt idea, that way i dont have to counter sink and weaken the already thin mounting surface but it offers a relatively smooth skid surface.

Originally Posted by chris demartini

What are you bolting it to?

its an open slate right now, but the vehicle is a cj7 with a 465 and 205, the 465 hangs down below the frame rails about 1" so i might make a dished skid

[92redyj]

I run 3/4" with no backing. The plate has dented in unsupported areas but I have enough clearance in the chassis that it isn't an issue.

[rokspydr]

1/2" uhmw backed with 1/4" aluminum. mounted with 3/8" countersunk allen bolts. 5 years and no problems. And its real light

[rockcity]

Originally Posted by bamatj51

Some people claim that the white is stronger than the black. But I have also read they are the same. Anybody know the truth?

The white has better impact resistance but the black has better wear resistance. The white is virgin while the black is recycled.

[dboy]

Im going to be doing a flat belly with a uhmw skid soon and am looking at my options and was thinking 1/4" uhmw to 1/8" steel. but you guys are talking 1/2" and 3/4" plastic! But i think a key factor that isnt being looked at is How heavy are your rigs that this is going on?

i dont think that a 4klb rig need 3/4" plastic with 1/4" alluminum, but then again a 7klb rig might. First glance at that rzr skid looks really thin and flexable but a rzr is under 1klb.

my .02sense

[DownNDirty]

Mine is 1/2 inch with a small backing frame. Biggest open space without a support is probably 10"x18". Runs the entire length of everything I care about. Buggy is right around 3500lbs. I do have to say watch out for exhaust heat. I blew a hole in my muffler running back out to the road from pritchett canyon and it melted my skid and all my poly mounts for the trans. The skid still works but it isn't flat anymore.