Bending Multiple Bars

[stephen aish]

hi guys,

i have started bending 2 and 3 bars at the same time and was wondering how they would total as i am limited with the weights i can use on my loading pin.

for example:

i tested 2 x 75lb bars and they only bent past 20 degrees when 70k (154lb) was placed on the pin. so here the formula is A+B

i also horseshoed 3 x white nails together -360lb but could only partial a 370lb bar i made so again it appears to be A+B+C

has anyone tested a strong and weak bar and found similar or different results? say a 300lb bar with a 100lb and found a 400lb result or something similar, or am i wrong in thinking the resultant weight is always that of the combined strength of each bar?

thanks for your help

stephen

[RSW]

David Horne has some numbers on bending two 60D nails. It is definitely not 2*A, more like 1.4*A, IIRC.

[stephen aish]

so far i have found it is 2 x A as 2 x 75lb bars went at 150lb. however, i am interested in peoples findings with 2 different bars at heavier weights-say a blue and a white or 2 x yellow etc.

stephen

[bender]

You will experience the combined strength. There shouldn't be any funky physics happening there.

Personaly, I've tried adding 1/8" HRS to 60D's as a way to progress. The 30 or 40 lb increase is a good way to progress and a tiny little piece of steel makes a big difference when bending an allready hard 60D.

On the other hand, I found it a bit awkward and time consuming so just stick to bending 60D's. I now use it more as a once-in-a-while test to see how I'm progressing.

[stephen aish]

thanks Bender,

i have started adding 4mm and 5mm to tougher stock and as you say there is a slight difference and these "loaded" bends are a good way to test your current level now and then.

thanks for the help and info

stephen