bencrush Posted February 12, 2019 Share Posted February 12, 2019 @acornI thought of you first. But I don't think 1/4" Brass is on your list of calibrations. It should be easier than the same diameter HRS. But HRS varies all over the place. A guy new to bending messaged me a few nights ago asking this question. He apparently got "gifted" almost 100 FEET of 1/4" Brass from his parents. I thought that their gift was very nice, but also kind of hilarious. And expensive! Anyway, that's what he has to work with now and he's curious what it compares to. I told him it was easier than 1/4" HRS, but didn't have any estimations strength-wise that I could throw out to him. He started with 3/16" CRS and bought a bunch of that, but it was too easy. Then his parents surprised him by getting online (he's not in the US, so it might be metric they bought him now that I think of it) and ordering some metal they thought was "pretty" (brass) and slightly thicker to maybe challenge him a bit more, but without being impossible. So far he likes the feel of the brass, but I told him next time to buy something more reasonable, like 1/4" CRS or 1/4" HRS. Quote Link to comment Share on other sites More sharing options...
acorn Posted February 13, 2019 Share Posted February 13, 2019 Wow 100'! No never rated it. Probably could extrapolate based on cross sectional area difference to 3/8 brass. Might be able to tape 2 pcs together. 1 Quote Link to comment Share on other sites More sharing options...
bencrush Posted February 13, 2019 Author Share Posted February 13, 2019 2 hours ago, acorn said: Wow 100'! No never rated it. Probably could extrapolate based on cross sectional area difference to 3/8 brass. Might be able to tape 2 pcs together. Yeah, I'm still chuckling at the thought of 100 foot of 1/4" Brass being delivered. And that must've cost a small fortune even for that small diameter. I thought about trying to guesstimate based on the Golden Bastard ratings compared to 3/8" HRS... Quote Link to comment Share on other sites More sharing options...
wobbler Posted February 13, 2019 Share Posted February 13, 2019 My best bench racing formula (assuming same material) is to get the ratio of cross sectional area and ratio if moment of inertia, then add together and divide by two. So a 3/8 round bar, cross sectional area is .11045 in^2 and moment of inertia is .00970721397 in^4 1/4" round bar area is .04909 in^2 and moment of inertia is .000191747437 in^4. ((.11045/.04909) + (.001917... / .009707...) / 2) = 365.63 3/8 round brass should rate about 365% higher than 1/4" brass. I've checked this against different actual ratings I found for crs and drill rod, it seems to be pretty close. Especially for other shapes (square, hex) that definitely wouldn't make sense to just use cross sectional area to compare. It also shows a red nail at 200% of a yellow nail, which is pretty well accepted common knowledge I think. It's ~150% the cross sectional area, and ~250% the moment of inertia, average those and you get ~200%. 1 1 Quote Link to comment Share on other sites More sharing options...
acorn Posted February 13, 2019 Share Posted February 13, 2019 (edited) 14 hours ago, bencrush said: Yeah, I'm still chuckling at the thought of 100 foot of 1/4" Brass being delivered. And that must've cost a small fortune even for that small diameter. I thought about trying to guesstimate based on the Golden Bastard ratings compared to 3/8" HRS... If they got it from McMaster in 6' sections that would be about $200 and if they got it from Speedy Metals online, 3x that. Jeebus. Edited February 13, 2019 by acorn 1 Quote Link to comment Share on other sites More sharing options...
Mike Rinderle Posted February 14, 2019 Share Posted February 14, 2019 22 hours ago, acorn said: If they got it from McMaster in 6' sections that would be about $200 and if they got it from Speedy Metals online, 3x that. Jeebus. I need new parents 2 1 Quote Link to comment Share on other sites More sharing options...
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