Original Posted By: owner-pietenpol-list-server(at)matronics.com
The way I see it, you have 200 lb on the 6" side of a lever giving 2400 lbon the 1/2" side of the same lever (well, 5/8", but 1/2" is easier tocalculate). The top half of the tube will be in tension, and to the extentthat pi=3, you have about 0.2" sq inches of cross section (3 x 5/8 x .095).Total tension on the 4130 is 12,000psi. Since 4130 is good for 50,000 psior so, you should have a safety factor of about 4. Seems OK to me. Makesure that you have enough of a lever arm on the inside that you don'toverstress the wood where you anchor the 3/4" tube--spruce is only good forabout 900 psi across the grain (as I remember).Gene-----Original Message-----