blueovalz Posted November 23, 2006 Author Share Posted November 23, 2006 These are 3/4". I wanted to use the same size as was on the outboard ends. The 3/4" stud in the last photo (on the previous page) is simply a 3/4" grade 8 bolt with the head cut off and spot welded into the CA pivot tube. With the proper spacers, I should be able to bolt all of this together in a couple of hours. The key is getting the spacing down correctly so that I don't wear the bearings out. As it sets, the bearing retainers have a .0005 interference fit, and a light press seats them easily. This old photo shows my initial goal of using a rod end (bad idea), but now I see that the monoball assembly is definitely the way to go. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted November 25, 2006 Author Share Posted November 25, 2006 I fabricated the spacers and finally fitted the bearing retainers onto the CA as they would be in a final installation, and then compared it to a CA with the OEM rubber bushing. Quote Link to comment Share on other sites More sharing options...
LLave Posted November 28, 2006 Share Posted November 28, 2006 Jon, Ok I have some more questions. In the picture above, the red arrows is a toe adjuster right? But couldn't you get the same effect by adjusting out the rod ends on end of the LCA (green)? Is there some benefit to the red adjuster? Maybe on car adjustability? Also what is the rod end with the blue arrow for? Sway bar? Earlier I had asked you about the quality of the stock car products mono ball. I wanted to share with you what little I know about mono balls. In the industrial world they are called spherical bearings and are commonly available (link) in all types of ratings. Many are lined with PTFE which is just Teflon. Here is some generic information from global spec:Link The 4x4 rock crawler guys have a bunch of really cool high angle joints. Although they don’t do anything at high speed the sure do put a TON of load on there joints. They commonly use extremely long links on tires in the 40"+ range and gear ratios in the 300:1 range. A few to take note of are: Johnny Joints Ballistics Fabrications rebuildable joint Also here is a pretty good review on some link joints by pirate4x4.com although they are a bit massive:eek: Joint Review :eek::eek: Quote Link to comment Share on other sites More sharing options...
blueovalz Posted November 28, 2006 Author Share Posted November 28, 2006 Jon, if I may: The adjustment on the outboard ends do not have the "granularity" for infinite increments of movement. Basically, the smallest adjustment is 1/2 turn (180º) of the rod end. At 16 TPI, this then is an adjustment of 1/32" over a length of about 6.75" (on my set-up anyway). This equates to about 1/8" minimum toe adjustment (measured at the tire's OD) when making toe adjustments at the "green" arrow. If a turnbuckle at the "green" location were used, then infinitly fine adjustments could be made, but this introduces some complexity in design and strength (I hate excessive links and joints) in my opinion. At the "red" arrow, the adjustment can be infinitly small because the turnbuckle can be turned any amount, whether it be .005º or 360º (and in this example, can be used on any control arm, left, right, modified or not) Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 28, 2006 Share Posted November 28, 2006 Those joints are typical of the type that "beat out"... they must be constantly adjusted and rebuilt... The other consideration is that they are made to give a little... they are designed to allow freedom of movement in all direcitons... they were not designed to maintain race car alignment... And considering they do not use the typical 5/8" and 3/4" bolt sizes that most >2500lb race cars use... they are not very tough... they are probably depending on them breaking to avoid frame damage... the last thing you want on a race car is breakaway suspension parts... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 28, 2006 Share Posted November 28, 2006 I think the other guys covered the rod end and monoball choice pretty well, as well as explaining the toe adjuster's benefits. Here is a link to a thread with more info on the swaybar and how the blue rod end works. I think my swaybars turned out REALLY good: http://forums.hybridz.org/showthread.php?t=105596 Quote Link to comment Share on other sites More sharing options...
LLave Posted November 29, 2006 Share Posted November 29, 2006 ohhh now I understand. Thank you, Terry for taking the time to thoroughly explain the concept to me. Keep the good schooln' coming. Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 7, 2006 Share Posted December 7, 2006 I fabbed up my new rear LCAs... I did much the same thing that JM did for his outers... I will say that this adds weight... So for those of you who want to keep weight to a minimum... go with the tubular arms... I chose to use the G-Machine aluminum/delrin bushings inboard for fine adjustments and to improve roll center... I made a jig to hold the long 5/8" bolt for the outers and I mounted the inner ends with screws... the new piece matches the original exactly... The arms picked up a great deal of stiffness with the modification... they ring like a bell now and they are MUCH HARDER to twist than the original floppy design... I can extend them nearly an inch.. I can shorten them by 1/4"... Sand blasted, etching primer, silver wheel paint.... I used 1.5" 0.080 wall(14g) square tubing... The threaded tube ends are extended by an internally welded section of 1" pipe... I also welded most of the outside of the joint as well... I welded everything with 2 bolts in the threaded pieces.... I used a die grinder and ran a tap through to clean up the end threads when it was cooled... I went VERY short and slowly with the welding to keep heat to a minimum... The arms were also straightened and seam welded in the jig to ensure a stiff straight piece... These babies ring like bells... ... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 7, 2006 Share Posted December 7, 2006 What size tube did you use? 1.5" square? Looks a bit bigger than what I used, and I chose the tube I used because the tube ends just met flush with the other side. Yours looks like there is something sticking through on the inside. You must have had to add some tube to the inside of the tube end to get it to go all the way through or something. I think mine added 1.5 lbs per side or thereabouts, took the weight of the arm from 8 lbs to ~9.5 I think. I also have all the sway bar attachment points on my arms as well. I weighed the arm after I welded it all up, but I can't find where I wrote down the weight. I thought I posted it here, but I can't remember where, and I don't see it in this thread anywhere. I'm not too worried about it really, as I think the freedom of motion from the monoballs and rod ends is far more important than a lb of weight. I did struggle with the idea of using the G Machine bushings on the inside, and I think that's a decent way to go, especially if you don't want to make the toe adjuster that Terry and I have. One thing you might want to check is for bind at the top of the strut with the toe setting you want. In order to get any toe setting other than 0 you will have to adjust the front and back bushing differently. This will lower either the front or the rear bushing, and that will tilt the whole control arm. I think that you'll probably be OK, but you may end up running into that major side load on the strut that I was so worried about. Something to check for anyway. Looks good though! I really love seeing other peoples' interpretations of these ideas. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 7, 2006 Author Share Posted December 7, 2006 Another convert! Good job. Thought Jon was posting more pics when I first saw them. Anyway, I am curious about the adjustment window on these heims. The statement: I can extend them nearly an inch.. I can shorten them by 1/4"... made me wonder about this. What is the industry recommendation on the minimum amount of thread used to support the rod end. Is it 1.5 times the diameter, or some general factor such as that? When I fabricated my ends, I began to wonder just how small the adjustment window would be. Based on the 1.5* factor above for a 3/4" rod end, I'd have: 1 1/8" (penetration) + ~3/8" (jam nut, but it may be thicker) = 1 1/2" thread use at maximum extention, which leaves about 1/4" maximum adjustment window for safe operation. I allowed for a bit of adjustment on the inside movement (1/8"), which at that position only allows me to extend the joints another 1/8". Even at 1* factor (and this would be iffy IMHO), I'd have have a total window of 5/8", which leaves me only 1/2" movement outward, but is a 1* factor resonable and safe? I realize most loading on these joints will be under compression and tension, but there will be some shear forces introduced as well. At what point is the amount of thread engagement (or lack of it) risky? Anyway, something to review. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 7, 2006 Share Posted December 7, 2006 I heard 1.5x the diameter years back, and I've stuck to that recommendation. I don't know that it is a recognized rule of thumb so much as the recommendation of the particular guy who made my TC rods and front control arms. It seems a little strange that you would have so much less available adjustment as the rod end gets larger. Maybe that's in anticipation of more loading, but your larger rod end in the same position on our control arms should be able to adjust at least as much as the 5/8" end safely, because it has a lot more thread engaged due to the larger diameter. At least that's my gut feeling. The other thing is that the longer the rod end is the more of a bending moment there is on the threaded part of the rod end. This is typically considered a no-no, and many engineers would look at what we've done and shake their heads because it is a "bad" idea. The longer you make the control arm the worse the idea becomes. Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 7, 2006 Share Posted December 7, 2006 It looks like my previous estimates were wrong.. looking at the rule that would allow ~5/8" of extension... but that is still a lot... Quote Link to comment Share on other sites More sharing options...
LLave Posted December 7, 2006 Share Posted December 7, 2006 What is the advantage of a spherical bearing over a heim on the inner control arm pivot? A heim is essentially a monoball on bolt, no? Why not just used heims on both inner and outer ends? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 7, 2006 Share Posted December 7, 2006 It's hard to use a rod end on the inside because there is nothing to attach it to. I think the monoball is easier to install and requires less modification to the control arm. The advantage to this type of joint vs a bushing is the reduction of friction and the accuracy of the movement (lack of deflection). Comparing one to the other I don't know that there is a particular advantage to one over the other. It's the same type of joint, it's just attached to the suspension differently. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted December 10, 2006 Share Posted December 10, 2006 I heard 1.5x the diameter years back, and I've stuck to that recommendation. I don't know that it is a recognized rule of thumb... Yes it is a recognized rule of thumb in the engineering world. Cameron Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 12, 2006 Share Posted December 12, 2006 I had stated earlier in this thread that the modifications would add weight to the rear control arms... While the modifications to the outboard end DO add weight... It has come to my attention that some of the tube fabricated arms actually weigh as much as 15lbs EACH!!!! I weighed mine and they come to 10 lbs 9 oz with all of the hardware to mount them including the inner and long outer bolts, spacers, nut, etc.... That aint too bad considering... Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 12, 2006 Author Share Posted December 12, 2006 Nice work. I "felt" the same way about the weight. I think with the added stiffness of the arm, this is a very small penalty. Quote Link to comment Share on other sites More sharing options...
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