Les,
IMO, the best idea is to attach a u-bolt with a hoist point bracket to
the mast and use a come-along inside to the tower top plate, although
come-alongs can be too long to fit. The shortest headroom lifters I've
found is are 500# and 1000# capacity lever chain hoists, < 8". This is
my strategy for a safe very heavy mast lift off the rotator, even if a
foot or more of clearance is needed. A forged eye is fitted to a hole
drilled in the top plate of the tower as an attachment point. Once
installed, the attach points can be left for the "next time".
Other ways to go: the die pry bar set from Harbor Freight and the 4 ton
hydraulic frame straightener have been very handy for me to
lift/separate/straighten things.
#68339 or #1654 (the porta power from HF is now 2x the price from Amazon)
http://www.amazon.com/Goplus%C2%AE-Porta-Power-Hydraulic-Repair/dp/B017H8R9E2/ref=sr_1_1?ie=UTF8&qid=1461551404&sr=8-1&keywords=hydraulic+frame+repair+kit
the jaw separator might be useful for lifting once a pry bar gives some
space for it, but needs a good purchase. Or use the small extension
cylinder to a u-bolt fastened lift point above the tower top. Or use a
small scissor jack, which I bought for taking apart rohn 25. The
cylinders are also good for straightening bent tower parts.
On a used 2800 I acquired the prior owner had secured a cut off box end
wrench on the center bolt with a screw through the wrench handle and
threaded into the Orion plate about 2" out from the bolt, oriented so
the split mast clamp clears the wrench. Now I know why he did that.
Grant KZ1W
On 4/24/2016 19:11 PM, Les Kalmus wrote:
I came home from Visalia to find my antenna system freewheeling. The
mast holds 4 yagis, one of which is very large, and is rotated by an
Orion rotator.
If my suspicions are correct, the problem is the little 1/4" bolt
holding the shaft up into the bottom of the mast clamp has loosened
and allowed the shaft to fall.
The tower is lowered and the antennas are tied off to a tree. I have
removed the mast clamp and now I have to raise the mast about 1/2" to
free the centering block so I can remove it to inspect that bolt.
I have a come along with an additional block with which I can lift the
mast, but the carabiner I have won't fit into the small space between
the centering block and the inside of the mast.
Any suggestions on a way to either hook the mast from the bottom or to
clamp to it so I can raise it? We're talking maybe 400 lbs in the
complete antenna system.
I have done this in the past but I think I didn't have the centering
block at that time so it was easier to get something hooked into the
bottom of the shaft.
Les W2LK
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