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Calibration Of Braced Bars


Cunny

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Cunny,

I've talked about this to several people before and so far no way to do it. I'll go out on a limb and say that you may be suprised just how low the numbers would be for the long 3 and 4 footers. I'm betting 5/8 by 4 foot would be well under 200 lbs, maybe around 150 or so. Could be totally wrong here but even if you look at the spikes, the 10 inch FBBC hit 290 lbs which is about the same numbers as a decent 60d and I guarantee there are alot more 60d benders on this board. Would be alot harder bend then one of the easy spiral 80d spikes that calibrate around 350 to 400.

Basically, just like we've discussed the differences between 6 and 7 inch unbraced bends, I think the same applies to the longer stuff. I've had some 8 inch spikes calibrated so I can guess what stock at 8 inches would be but longer than that would be hard.

We'd just have to compare stocks of the same length and for that a calibration system would be great. I know I questioned Eric about doing some of my shorter 1/2 inch bars but his clamps will only accomodate 3/8 inch and possible 7/16.

Also would be neat to find a way to calibrate wrenches.

If anybody does try this, keep in mind that to be accurate to what your body feels, you'd have to have a center fulcrum that was as wide and dull as your knee or whatever body part you bend with. If you had just a center carbiner, it would take significantly less force.

I think David's system he used for the challenge bars would work really well if you took all the different stock and just did say 3 foot pieces.

Good thought. Hope somebody comes up with something.

Tim

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I think with some bigger clamps, a bigger carabiner, and some longer chains, my device would give some meaningful results for the longer, thicker steel. But, as usual, all of Tim's points seem to be valid.

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I shouldn't be too hard to create a device based upon the device Eric has.

Maybe if I have some spare time I will set something up which I can hook up to my powerrack.

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Good points Tim. You're right, it probably would be a lot easier to calibrate than the short bars I used to do. Think my brain wasn't working last night after all the travelling. :blink

But it's something I haven't got time to do right now though.

David

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I tell you what suprised me and where I get some of my estimates, is that I had a 4 foot piece of 5/8 inch HRS and I was outside with it and to prove how strong the steel was I put it over a tree limb and was going to do some chin-ups on it and it bent some and at the time I was probably 180 lbs or so and I tried to put gradual force on it too.

I didn't mean to discourage anybody with my center carbine point. After all the calibrations are just a way of comparing the steel. Just because a 60d takes 300 lbs in Eric's device doesn't mean that's the number the hands feel, it may be much higher for that matter but it is a good way to compare to a G2 bolt at 200 lbs.

Eric, I would gladly purchase some larger clamps to accomodate thicker steel. I'd love to have some numbers for my 7/16 and 1/2 inch by 8 inch bars which I know you've done spikes so I'm guessing that would suffice? Other than the clamp your current system would be fine with 12 inch and shorter I'm guessing since you've done the FBBC spikes? Of course since you cal'd a 80d at 590 lbs for me I'm betting the 1/2 inch at 8 inches may surpass your weight limit.

If I had a loading pin I think 3 and 4 footers could be done fairly accurately by hand. Maybe mark the center, put a towel around it and use a tow strap down to the loading pin then just make sure your hands are flush with the end and lift. However I don't think I have enough weight to do the 3/4 inch bars.

Tim

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Tim, I have no problem modifying my setup with a few extra parts at my expense, but I kinda figured people wouldn't be willing to send me 3 and 4 foot bars in the mail?

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Eric,

Personally I'm more interested in the thicker 12 inchish and under so that wouldn't be a big problem to ship.

Tim

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Eric,

Personally I'm more interested in the thicker 12 inchish and under so that wouldn't be a big problem to ship.

Tim

Okay, cool. I'll check the hardware store today for some bigger sized clamps.

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I bought some clamps that will hold easily hold 5/8" stock, but the largest carabiner I could find will only accept 1/2" stock, and that was after I filed it down. But I'm good for 1/2" stock now, anyways. Tim, if you can locate a quick release carabiner for thicker stock let me know. Just make sure the carabiner itself isn't more than 1/2" thick, or it won't fit on my chain.

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