Arm material.....

Ghost

Member Number 257
NAXJA Member
Location
Camden, SC
No not muscles and bones silly! Long Arms, radius arms, and links.... Round or Square which do you prefer? Which is better? Why? .25 or .375? Is .375 over kill?
 
Ghost said:
No not muscles and bones silly! Long Arms, radius arms, and links.... Round or Square which do you prefer? Which is better? Why? .25 or .375? Is .375 over kill?

A bigger diameter will gain you more strength (pound for pound) than a heavier wall thickness of the same diameter. 1.75" is good, but 2.00 is better. This is true both in bending and in tension/compression. 0.25 wall is a great start.

Also, a thicker wall tube will be better than a small wall sleeved with a bigger tube, i.e., 2" x .250 wall is far superior to 1.5" x .120 wall sleeved with 2" x .120 wall.

However for the best...PolyPerformance has pre heat-treated 4130 tube in made to order lengths. 2" OD x 0.188 or 0.250 wall 4130 H/T would be nearly unbreakable.

HTH
 
i used 2x2x.25 square tube turned corner down, works awsome and slides over rocks easily
 
steagall9301 said:
i used 2x2x.25 square tube turned corner down, works awsome and slides over rocks easily

so you made it so that it gets loaded in its weakest direction?
 
XJ_ranger said:
so you made it so that it gets loaded in its weakest direction?
ok, i guess so, you might be right, i dont know, i figured the corner is less of a friction point. although i was wrong, it is 3/8 thickness, i went in the garage after i wrote that and looked at the leftover stock, i really dont think that i will have any issues, and if i do then i will just have to make some newer and better ones. mabi a hidden 3 link or true long arm 4 link
 
steagall9301 said:
ok, i guess so, you might be right, i dont know, i figured the corner is less of a friction point. although i was wrong, it is 3/8 thickness, i went in the garage after i wrote that and looked at the leftover stock, i really dont think that i will have any issues, and if i do then i will just have to make some newer and better ones. mabi a hidden 3 link or true long arm 4 link

it is less friction, but the way that square is designed to be loaded puts the top in compression and the bottom in tension (assuming a top load - opposite for a rock under and axle and frame on either end), and the sides more or less hold them together... (contribute to the comression and tension as well, but not to the same effect)

by moving it over onto its side, you now have one corner in compression and one corner in tension... much less surface area in each type of stress - and have effectivly mounted it in its weakest direction.

at least - i think that is what Dr. Kearsten said 2 days ago... :D
 
XJ_ranger said:
....... effectivly mounted it in its weakest direction.

at least - i think that is what Dr. Kearsten said 2 days ago... :D

i wish he would have told me that 7 months ago when i built the setup:doh:
 
XJ_ranger said:
at least - i think that is what Dr. Kearsten said 2 days ago... :D

You maybe be right, it's pretty late here, but bending strength is determined by I, not the shape per say. Also loading on a corner seems fine as the rib, or bend is going to have more resistance to bending then a flat area, ie the sides. Also going to be less likely to dent.
 
I've been kicking this 2x2 arround in my head for a while. I saw some pictures of compatition rigs that had square or flat on the bottom arms and it got me to thinking why not. What abut holes to lighten them? Or would that weaken them?
 
Ghost said:
I've been kicking this 2x2 arround in my head for a while. I saw some pictures of compatition rigs that had square or flat on the bottom arms and it got me to thinking why not. What abut holes to lighten them? Or would that weaken them?
go on Pirate and search for bgreen's buildup thread in the Chevy section. he's done some awesome fab work. One of which was 2x3 arms that were a thinner wall (.120?) then he plated the key areas.
 
BrettM said:
go on Pirate and search for bgreen's buildup thread in the Chevy section. he's done some awesome fab work. One of which was 2x3 arms that were a thinner wall (.120?) then he plated the key areas.

I think he plated the wrong key areas if it's the same thread I'm thinking.
 
Dirk Pitt said:
I think he plated the wrong key areas if it's the same thread I'm thinking.
yeah, there was some debate there regarding him plating the sides. personally I don't think with 2x3 oriented vertically he has to worry about bending them anyway, the key plating to me is doing the bottom to resist denting.
 
I'm not concerned with plating bc I'll use .25 tube when I do it. I ordered the JJ's earlyer. I just have to find out if my friend that is doing the bends can bend square.... :wierd: as for Pirate I lurk there but hardly ever post, too many asshats who have no tact and respect for each other for me to do that.... JMHO of course...

Glenn "Pirate Hatter" Ghost
 
i used 2x2 .250 for my extended radius arms and jonny joints and i dont see those bending easily i havent yet wheeled it so i geuss ill see
 
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