[TowerTalk] Crank-up tilt-over tower for a newby

[Patrick Greenlee]

While reading about a tilt plate for a tower by following a link generously shared here by a fellow tower enthusiast I noticed lots of comments regarding the DANGER of crank-up/telescopic towers.  The negative comments were made as if they were universally applicable and true but... there was nary a hint as to what any of the danger was.

Maybe some of you tower experts can fill me (a neophyte tower guy wanna be) in with the real deal the poop from group.

I was given a triangular Crank-up tilt base tower consisting of 12 inch on center square tube legs 1X1 inch 20 ft long with a  telescopic section of 20 ft + a tapered triangular portion terminated in a steel tube.  Overall extended length of the tower from base to top of tube is 41 ft and a couple inches. This will grow a few feet mounting a rotor and hex beam.

I replaced the hand winch and cable with a small 120VAC winch with new cable, installed a new bearing in the pulley, welded on some metal on the pulley where corrosion had made for missing pieces, and filed the welded metal to the right shape and as smooth as peach fuzz. 

I welded a "C" channel to the tower at the 7 ft level from the bottom. One edge of this C channel has sections of black iron pipe welded to it forming half of a piano hinge which mates to the other part of the piano hinge which is a piece of channel welded to the top of a 4 inch ID 1/2 inch wall thickness steel tube 15 ft long. I have welded three pieces of pipe as extension to the bottom of the 15 ft tube. There is a 2 ft overlap of the extensions where they are welded to the 4 inch.  They are arrayed 120 degrees apart and braced by welded on steel braces.

I intend to stand this assembly up in a 2 ft diameter hole about 7 ft deep with a 3x3 ft square formed around the hole about a foot thick which will adequately cover the weld joints of the welded-on extension assembly which is 2 3/8 inch OD steel pipe.  I intend to guy the stationary (lower) 20 ft section at its top but not guy the movable section.
When the tower is put in place and the hinge pin inserted in the piano hinge it can be tilted vertical and lowered to whatever height including to the ground by pivoting the 7 ft bottom portion below the hinge.  I intend to add an extension handle (cheater bar) to the bottom of the tower to gain leverage so I can manually tilt the tower up and down with out a come-along, winch or block and tackle. I weigh about 220 dressed so with a rotor and hex beam on top I will be able to raise and lower the assembly with reasonable effort (with the upper section retracted fully of course.) The welded on extension/cheater bar will just clear the 3X3 pad and will strike a steel ramp when approaching vertical.  This will transfer most of the weight to the contact of the tower extension cheater bar handle to the concrete base and essentially unload the hinge.

When the tower is vertical a hole in a steel piece welded to the tower will align with a hole in a piece of steel welded to the 4 inch pipe and accept a pin to secure the movable portion of the tower to the fixed base.

I would entertain comments and suggestions on any aspect of this kluge but I am particularly interested in comments form anyone experienced in designing/building limit switch implementations.  Unless otherwise convinced I intend to use either magnets and reed switches or micro switches with long flexible levers to accept a little overshoot. I haven't quantified the overshoot (how far up or down the tower moves after the power to the winch is removed) because I haven't had the tower vertical since refurbishing it. I suspect the overshoot will be minimal as the line speed is not too great,

If you think your response will not be of general interest then please PM me. I am good on QRZ.com AF5CK

I’m getting very close to being able to GIT ‘ER DONE!!

Thanks for any consideration,

Patrick AF5CK

P.S. Rustoleum brand “Hammertone finish” paint uses no primer and goes on over light rust, passivates the rust and offers a good appearance for many years. I painted it on rusty metal square steel tubes in an outdoor application almost 10 years ago and they all still look like new.  So I painted the tower with it.