Mack Posted March 23, 2008 Share Posted March 23, 2008 hey all, i have to make a custom front control arm to put S13 coils on my 280ZX, my question is, would 6061 aluminum in a 2.5" x 1.25" box with 1/8th inch thick walls be adequate in terms of strength? Or do I need to go with solid aluminum? Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 23, 2008 Share Posted March 23, 2008 If you do use a box, you cannot have any bolts go through the box that do not have a tube on the inside so the box does not collapse. If you have the correct tubes, you should be OK. I would use 7075, for fatigue resistance. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 24, 2008 Share Posted March 24, 2008 WIth your "new cad system" you were bragging about the other day. ( hehe) You should just draw something up in a .dxf file for a cheap 2d cnc profile, and get something done out of billet. Should not be two expesive. And although, if you drew me a print of what you wanted, I could make the stuff for you, but if you do a .dxf file you have to create a print to go with it. If you do a parrasolid, iges, solid works file, etc. I can import it in 3d, and you dont have to create a paper print. Quote Link to comment Share on other sites More sharing options...
Mack Posted March 25, 2008 Author Share Posted March 25, 2008 Im going to drill all the bolt holes in a solid 1" thick peice of aluminum and then weld it on to the end of the box control arm. For the sway bar mount, I will weld a gussetted mount on the side for the arm. and the part where it mounts to the crossmember will just get a thick wall tube, the proper size for my new urethane bushings, welded to the other end of the box. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted March 25, 2008 Share Posted March 25, 2008 That seems like a whole lot more work with possibly more weak points than just using a solid piece of aluminium, and with very minimal weight gain at best. I don't recall the exact length of the stock control arm, but at somewhere around 10", you'd only have about 5 to 6" that is this tube. Doesn't seem like it's worth the effort to do it this way. Quote Link to comment Share on other sites More sharing options...
Mack Posted March 25, 2008 Author Share Posted March 25, 2008 new control arms have to be about 15.5" from center of bushing to center of ball joint, where as stock control arms are about 14.5". so, the actual box part will be about 12 to 13". I may just go solid, as I do not know how strong the aluminum will or wont be. that was my main question. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted March 25, 2008 Share Posted March 25, 2008 I missed the "ZX" in your original post, the S30 front control arms are shorter, the exact length was posted on here a day or two ago. I still believe that the possible weight savings won't outweigh the additional labour and possible weak areas, as compared to a solid or billet piece, if there would end up being a difference in weight. Quote Link to comment Share on other sites More sharing options...
katman Posted March 25, 2008 Share Posted March 25, 2008 Keep in mind 6061 isn't the most weldable (not like a 5000 series anyway) and it's strength is crap compared to REAL aircraft grade aluminum (like a 7075-T6) or most steels. Whether or not it's strong enough will depend a lot on the details of your design. Quote Link to comment Share on other sites More sharing options...
Mack Posted March 25, 2008 Author Share Posted March 25, 2008 yeah, looks like I might just end up making the control arm out of solid, 1" thick aluminum. I think the stregth should be sufficient. Quote Link to comment Share on other sites More sharing options...
2126 Posted March 25, 2008 Share Posted March 25, 2008 Keep in mind 6061 isn't the most weldable (not like a 5000 series anyway) and it's strength is crap compared to REAL aircraft grade aluminum (like a 7075-T6) or most steels. Whether or not it's strong enough will depend a lot on the details of your design. I highly suggest you do a little homework on aluminums before making such a statement. Tom Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 25, 2008 Share Posted March 25, 2008 I highly suggest you do a little homework on aluminums before making such a statement. Let's keep it civil guys. My understanding is that Keith is an aeronautical engineer, so not the kind to talk out of the wrong hole... Quote Link to comment Share on other sites More sharing options...
DrSideways Posted March 25, 2008 Share Posted March 25, 2008 Let's keep it civil guys. My understanding is that Keith is an aeronautical engineer, so not the kind to talk out of the wrong hole... +1 Katman would be the GU in Guru on such matters. He has been there done that got the shirt and bumper sticker. Alan Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted March 25, 2008 Share Posted March 25, 2008 What kind of machine work do you need to do these? I may be able to help out some. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 27, 2008 Share Posted March 27, 2008 6061 is fully weldable, and works well. 7075 is under NO circumstance weldable, nor is 2024. I would go billet, but I may be saying that because I have a machine shop . Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted March 27, 2008 Share Posted March 27, 2008 6061 is fully weldable, and works well. 7075 is under NO circumstance weldable, nor is 2024. I would go billet, but I may be saying that because I have a machine shop . I've always wondered what makes certain alloys or material not weldable. What is it that happens? Lack of flowability, poor joints, weakening if the base material? Quote Link to comment Share on other sites More sharing options...
katman Posted March 27, 2008 Share Posted March 27, 2008 6061 is fully weldable, and works well. 7075 is under NO circumstance weldable, nor is 2024. I would go billet, but I may be saying that because I have a machine shop . I didn't say it wasn't weldable, just not as easy as a 5000 series, and I didn't say 7075 was. Point is the design needs to be vetted before we could answer his question. And yeah, I'd go billet with your machine shop too- and 7075 doesn't gum up the cutters like 6061. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 31, 2008 Share Posted March 31, 2008 The strength of 5000 series is not NEAR enough for a controll arm, and you WILL bend it over time. I have tried, many procedures to welding the 70, and 20 series stuff. It always pulls apart under high stress applications, plus cracks. Quote Link to comment Share on other sites More sharing options...
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