DIY Stand for 50 Gal

kornphlake · 01-29-2008, 04:04 AM

Quote:

Originally Posted by PDX-PLT

A unformed loaded beam of douglas fir 1.5" wide, 5.5" deep, 20.5" long will deflect 0.0004" with a 100 lb. load.

A quite useless calculation as your lumber will never be consistent enough to actually measure .0004", it'll move more than that every time your heater comes on.

Do you want to do the same calculation for a 1.5x3 .125 wall aluminum beam spanning 10 ft with a 250lb load at the mid point? I was trying to get our lame-o CAD system to do the calculation but it wouldn't cooperate with me and I'm not sure where my statics book ended up after the move.

PDX-PLT · 01-29-2008, 05:33 AM

Quote:

Originally Posted by kornphlake

A quite useless calculation ...

I disagree. The pont was to refute the concern that the beam may sag significantly. It clearly will not.

kornphlake · 01-29-2008, 06:27 PM

Oh, no I mis typed, the calculation is valid and scientifically proves the point. Good on you for actually running the numbers instead of a giving a gut feeling or SWAG.

The result of .0004 is pretty useless to try and measure. I'd say any deflection less than about 1/32 is insignificant or un-measurable because of the unstable nature of wood.

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01-29-2008, 06:27 PM	#18 (permalink)
kornphlake Planted Tank Obsessed (View User Tanks) PTrader: (1) Join Date: Dec 2007 Location: Portland Posts: 311	Oh, no I mis typed, the calculation is valid and scientifically proves the point. Good on you for actually running the numbers instead of a giving a gut feeling or SWAG. The result of .0004 is pretty useless to try and measure. I'd say any deflection less than about 1/32 is insignificant or un-measurable because of the unstable nature of wood.

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