minimum rollcage tube size

[milesstarkey]

i'm going to build a custom cage, and wondering how small would still be safe?

 

[woody]

for the A-hoop, B-hoop, and two outside stringers, 1-3/4 x .120 wall DOM is the minimum....you could consider 1-1/2", but I'd only do that if your rig will end up in the 3500# or less range. If you do a C-hoop family cage, then keep it .120 as well...if just straight bars back from the B-hoop, .095 1-3/4 is fine.

For any hoop v-bars, seat mounts and such, 1-1/2" x .120 or .095 works well....I'd keep .120 overhead tho, .095 dents a bit too quickly (BTDT)

Personally, I'd stick with DOM for material too...good strength to price ratio, CroMo is boo much $$$ and HREW/CREW is a bit under strength for me....

next opinion??

 

[Mace]

Woody is right, although I see no reason to stray from Hrew..

The strength increase is not that great..

 

[Radd Cruisers]

In saying the DOM would make a good cage at 1 3/4 with .120 wall, what would a tube chasis be built with?

Would be cool to have a coloured cage in the Tech section with heading showing material choices, dimensions, wall thickness.

And add lower links along with it with vehicle weights.

 

[Gumby]

I thought the big reason to stay away from HREW is just the difficulty in bending it.

 

[woody]

tube chassis can actually get away in some cases with smaller diameters, since the weight usually runs in the 3000# range. hard part in a tube project is ensureing the wall thickness of some of the lower mount points is enuf...almost need .250 in some places to keep things from tearing thru.

 

[Mace]

I thought the big reason to stay away from HREW is just the difficulty in bending it.

Most cages are built from HREW
It bends just fine. You just usually have to make sure that the seam is on the INSIDE of the bend..

 

[BJ40 3B]

Can someone expalin me waht is HREW???

 

[cruiserrg]

For my entire chassis I used (no weight yet as I am not done, but will be heavier than a comp rig):
1.75"OD 0.120wall DOM 1020 mild steel for chassis frame, cage, and upper links
2.00"OD 0.250wall DOM 1020 mile steel for lower links
1.25"OD 0.120wall DOM 1020 mild steel for window tubes
1.00"OD 0.120wall DOM 1020 mild steel for gussets

Now if I was going to make it again and lighter I would use 1.50"OD 0.120 wall DOM 1020 for the six point cage and frame rails, and then 1.50 and 1.25" OD 0.95 wall DOM 1020 for everything else.

If I was going for ultra light weight (like a comp rig single seater):
Chromoly alloy steel A 519 grade 4130 1.50” OD with .090 minimum wall for roll cage and chassis
Chromoly alloy steel A 519 grade 4130 1.00” OD with .083 minimum wall
Solid 1.75"OD 7075 T-651 aluminum for upper links, and Solid 2.00"OD 7075 T-651 aluminum

 

[Mace]

hrew = hot rolled electric weld

Dom is just HREW that has been passed through a mandrel to make it consistant.

 

[Gumby]

Can someone expalin me waht is HREW???

I'm sure there are those who know better, but my understanding is that it is Hot Rolled Electric Welded, meaning it is flat hot rolled steed formed into a tube and welded electrically. It has a seam that is difficult to bend.

 

[cruiserrg]

One thing to consider in the discussion of HREW and DOM is the properties (and the fact the HREW you buy at suppliers is usually 1010 and not 1020):

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1020 DOM STEEL TUBE

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1020 is normally used in the manufacturing of small-diameter or thin-wall DOM steel tube. DOM is formed from strip and electric-resistance welded, then cold drawn to size. The cold drawing process causes the weld line to virtually disappear.
American Specifications: ASTM A513 Type 5

British Specifications: 040 A 20, 070 M 20

Applications: Mechanical, hydraulic cylinders, shaft, tight tolerance requirements

Size Range: 1/4" - 14&1/2" (6 mm - 368 mm) OD; .035" - .625" (.9 mm - 16 mm) wall

Typical Chemical Analysis: C .15-.25
Mn .30-.60
P .040 max
S .050 max

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Typical Mechanical Properties: Tensile strength (ksi) 80
Yield point (ksi) 70
Elongation (% in 2") 15
Rockwell hardness RB80



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1018 COLD DRAWN AND HOT FINISHED SEAMLESS TUBE
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1018 is normally used in the manufacturing of cold drawn and hot finished seamless tube. The production of seamless tube is generally made by piercing a hot rolled bar. Hot finished is generally furnished in the unannealed condition, whereas cold drawn seamless is supplied in the unannealed or S/R annealed conditions, depending on the size.
American Specifications: ASTM A519

British Specifications: 070 M 20, 080 A 15

Applications: Axles, shafts, gears, bearings

Size Range: 1/8" - 24" (3 mm - 610 mm) OD; .0218" - 3.00" (.6 mm - 76 mm) wall

Typical Chemical Analysis: C .15-.20
Mn .60-.90
P .040 max
S .050 max
Typical Mechanical Properties: CDS HFS
Tensile strength (ksi) 80 60
Yield point (ksi) 60 35
Elongation (% in 2") 15 30
Rockwell hardness RB88 RB60



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1010 ELECTRIC WELD STEEL TUBE


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1010 is normally used in the manufacturing of electric-resistance welded tube. The product is available normally in cold rolled strip (16 gauge and lighter), and hot rolled strip (.083" wall and heavier). The product can be obtained in the as-welded condition (flash-in) or in the flash-controlled condition.

American Specifications: ASTM A513 Type 1 and Type 2

British Specifications: 040 A 10, 045 A 10

Applications: Machinery stands, exhaust tubes, handles, hand rails, display stands, conveyor rollers

Size Range: 1/4" - 10" (6 mm - 254 mm) OD; .028" - .375" (.7 mm - 10 mm) wall

Typical Chemical Analysis: C .08-.13
Mn .30-.60
P .035 max
S .035 max
Typical Mechanical Properties: Tensile strength (ksi) 45
Yield point (ksi) 32
Elongation (% in 2") 15 min
Rockwell hardness RB55 min





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1026 STEEL TUBE


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1026 grade is normally used in the manufacturing of DOM, cold drawn seamless and hot finished seamless. This grade normally furnished over 2" OD, with walls heavier than .156". A variety of thermal treatments can be supplied, depending on the type and size of material.

American Specifications: ASTM A519 (SMLS), ASTM A513 Type 5 (DOM)

British Specifications: 070 M 26

Applications: Mechanical, hydraulic cylinders, shaft, tight tolerance requirements

Size Range: 1/8" - 24" (3 mm - 610 mm) OD; .028" - 3.00" (.7 mm - 76 mm) wall

Typical Chemical Analysis: C .22-.28
Mn .60-.90
P .040 max
S .050 max
Typical Mechanical Properties: CDS DOM HFS
Tensile strength (ksi) 87 80 70
Yield point (ksi) 72 70 47
Elongation (% in 2") 10 10 28
Rockwell hardness RB89 RB85 RB78

The above was from a thread on pirate4x4.com http://www.pirate4x4.com/forum/showthread.php?t=133117&highlight=hrew+1020

 

[Radd Cruisers]

Now thats the information I was looking for......

Good work

 

[xjnation]

Can someone expalin me waht is HREW???

I called a local steel shop yesterday pricing some HREW. He said "hold on" and I heard him ask somebody what HREW was. Time to find a new supplier.

 

[chappysfj40]

so is this why they say DOM is seemless??? the way it is constructed.

 

[brokenparts]

I called our local steel yard here to get some pricing on DOM and HREW. His first question was why DOM? I told him I was thinking about building some armor or cage for my 60. He said he'd be happy to sell me the DOM but there really was no reason for th DOM unless it I was running an axle through it or was in a Race Car application. If its a questionable area I would run DOM but I see plenty of cage applications where people have no problems with HREW.

 

[Mace]

so is this why they say DOM is seemless??? the way it is constructed.

Yea, but DOM does have a seam..


And brokenparts has it. DOM is nice but lots of safe cages out there are made out of HREW.

 

[chappysfj40]

yes, but is it a seem but commonly refered to as seem less?

 

[John Smith]

I called our local steel yard here to get some pricing on DOM and HREW. His first question was why DOM? I told him I was thinking about building some armor or cage for my 60. He said he'd be happy to sell me the DOM but there really was no reason for th DOM unless it I was running an axle through it or was in a Race Car application. If its a questionable area I would run DOM but I see plenty of cage applications where people have no problems with HREW.

I am curious as to the price difference between the two per foot?

 

[brokenparts]

HREW commonly sells for about $3 a foot and DOM $6.50 a foot.