Scott Styles Posted June 19, 2007 Share Posted June 19, 2007 My order came from McMaster today. I got an 8' bar of 1/2" 6063 Aluminum. It is the exact same difficulty as 5/16" CRS. I took down a 12" piece braced, then got stuck on a 10" piece braced. That's exactly where I get stuck with the 5/16" CRS. All you bending monsters - this is the stuff for your thickest bend. Someone taking down bastards and above will be able to take down a 7" piece of this stuff unbraced. I can't even guess what length and diameter Tim would be able to take down braced. This is cool stuff to bend, and it's available online from McMaster Carr. The 8' bar only cost me $12. Here are sizes, part numbers, prices for 8' of the 6063: Diameter Part Each 3/8" 1640T31 $7.221/2" 1640T33 12.253/4" 1640T35 23.901" 1640T37 42.53 The website is: http://www.mcmaster.com Show us what you can do. Quote Link to comment Share on other sites More sharing options...
Tim71 Posted June 19, 2007 Share Posted June 19, 2007 Nice job and sounds fun! I've only ever bent one piece of aluminum that Chris Rider sent me and it was 3/8 by 7 inch and that was pretty easy unbraced. It cracked when I crushed it on down. Are you pushing down over your thigh or pulling around your knee, then how are you finishing it? Thigh master crush as Chris R calls it or posting on one leg? That's a pretty big jump from 1/2 to 3/4 inch. I think A36's yield strength is 36,000 KSI which should be 2.2 times the PSI rating of the aluminum if my science is right so I think there's a decent chance I might get a spike length bend from the 3/4 but the cross sectional thing really comes into play with the fatter and shorter stuff. Might have to try that sometime. Thanks for the idea. Tim Quote Link to comment Share on other sites More sharing options...
Scott Styles Posted June 19, 2007 Author Share Posted June 19, 2007 Tim, I really don't know what I'm doing with the spike bending yet. I seem to do better pulling around my knee than pushing down over my thigh. I resisted pulling around the knee since it places a lot of pressure on the patellar tendon, but it just works better for me right now. I've been posting the bar on my leg to finish it. I tried the thigh master crush, but couldn't make it work. Based on the fact that the 1/2" 6063 aluminum feels as hard as the 5/16 CRS, my math tells my the 3/4" aluminum should be a little easier than 1/2" CRS. I don't know how that compares to 1/2" HRS. The 1" aluminum would be 1.75 times hard than the 3/4", so that would have to be bent as a bar, I think. Pretty expensive bend. I did bend the 12" piece of 1/2" 6063 down to about 1/2" between the ends. It doesn't show any signs of splitting or cracking. I wonder if the guys running into that on aluminum were bending 6061. The 6063 is pretty soft. McMaster says it has half the hardness of 6061. It is the softest aluminum they sell in rod form. Quote Link to comment Share on other sites More sharing options...
ox3782 Posted June 20, 2007 Share Posted June 20, 2007 Great job sounds like fun to me!!! Brendan Quote Link to comment Share on other sites More sharing options...
honk Posted June 20, 2007 Share Posted June 20, 2007 The 1" aluminum would be 1.75 times hard than the 3/4", so that would have to be bent as a bar, I think. No, it wouldn't. The "resistance against bending" increases by the 3rd power. As a rule of thumb if you increase the diameter by 25% you double the "strength" of your rod. Quote Link to comment Share on other sites More sharing options...
Scott Styles Posted June 20, 2007 Author Share Posted June 20, 2007 I thought it increased directly with the cross sectional area of the bar (ie, square the radius of two bars of the same material, used those values to compare). That seemed to hold true for the jump from 3/8" to 1/2". I never studied mechanical engineering, it's just what I've experienced. Quote Link to comment Share on other sites More sharing options...
honk Posted June 20, 2007 Share Posted June 20, 2007 That would be true if you would just pull on the rod. However if you bend it, you have to recognize the geometrical dimension of the problem. That's were the 3rd power comes from. All that applys only to elestically deformation, i.e. the kink. Things may differ if you put lasting hurt to your nail. Quote Link to comment Share on other sites More sharing options...
AP Posted June 20, 2007 Share Posted June 20, 2007 That would be true if you would just pull on the rod.However if you bend it, you have to recognize the geometrical dimension of the problem. That's were the 3rd power comes from. All that applys only to elestically deformation, i.e. the kink. Things may differ if you put lasting hurt to your nail. Does this seem to hold true to the calibration numbers? I have heard the 25% -> doubling the strength before but it seems that 5/16 and 3/8 steel would be much harder relative to 1/4. Quote Link to comment Share on other sites More sharing options...
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