The new mast is up - repost

[frackers]

Sorry about the big images last time folks - I wasn't paying attention to the pulldown list of image sizes as I cut n pasted then URLs in.

The new 11m mast is up and performing it job of keeping the mill up in the sky and allowing me to sleep well at night.

The 115mm pipe sits in a 'boot' which has all the extra bits welded onto it to make a tilt over tower - the pivot and socket for the gin pole and a hole in the bottom for the generator cables to come out of. The pole is not fixed into the boot, gravity is all that holds it in!

As can be seen, there are two fixings, the bottom one is the pivot, the top one I doubt I will use as if the guys fail then nothing is going to hold it up!

The pivot pin is a length of galvanised irrigation pipe, located with a couple of 6mm rebar 'R' clips and taking the whole weight onto a couple of railway sleepers (so called, actually 250x100mm posts) that are sunk 1.6m into the ground.

The cutout switch and the rectifiers are mounted on one of the sleepers.

With the gin pole slotted in, you can see how it goes together for raising and lowering

The gin pole has a 6mm HT wire rope going up the middle to connect to one of the guy wire turnbuckles to provide the lift from the horizontal up to about 60 degrees

To allow the guy wire to move away from the gin pole as the mast gets towards the vertical, the connection has to be slackened off - the wire rope up the inside of the gin pole allows this by slackening the clamp at the botton of the gin pole

A turn of 5mm HT wire rope making sure we have belt and braces on the guy wire adjusters. Each of the 4 guy wires has a turnbuckle in the same relative place, one of which has the gin pole attached to it during raising and lowering

Originally using the fence posts as the guy anchors, a few calculations showed that in excess of 400kg of deadweight would be much better.

If the 12mm rebar in the concrete fails then there is a turn of 5mm HT wire rope tying the guy back to the fence post.

Hard work, even with the 5 to 1 ratio of the winch, to get the pole up.

Since the raising side of the mast doesn't have its guy wire thimble directly through the anchor, double shackles for a restfull nights sleep

[Airstream]

Spotted the twin posts and Cut'n Pasted ULR's text in..

by Ungrounded Lightning Rod on Tue Mar 31st, 2009 at 09:50:13 PM CST

Should have put that loop through the turnbuckle center hole, too.  As it is now the turnbuckle can unscrew and then the force goes SNAP onto the loop.  Put it through the turnbuckle center as well as the ends and the turnbuckle can't unscrew.

Figure-8 through the core and the two wire loops where it is now.

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Nice post, thanks for sharing!

[thirteen]

You may have already done this. I'm not sure where you live but you might drill a hole in the bottom of the boot to let water drain out. If you are in a cold climate water might freeze and split the boot. You may want to seal the tops of your posts. A little extra cable for safty is a good idea. I would try and shorten them some because if one snaps or things break the momentom may be to much for the safty cables to hold. A little less slack might be better. Good job.  Just some ideas.

[Ungrounded Lightning Rod]

Another reason to avoid fastening the top fitting:  The pole will work against the boot and wear out.  You can accept that at the bottom of the boot:  Wear there will just lower the tower a bit until it finds a way to stick to the boot (like crumpling, spreading, self-welding, filling in with debris, etc.)  At the top it will weaken the tube and make a hinge point, eventually cutting through.

I'd also stuff some kind of circular wedge of material into the boot/mast crack to cushion the contact and encourage the boot and mast to move as a unit as the mast sways.  (It can also serve as a rain roof, though you'll still want the drain hole(s).)  You don't want it too solid or it will encourage stresses at the base of the mast inside the boot.

[frackers]

I'll be putting a turn of baling wire through the turnbuckles to stop them adjusting themselves - in the meantime, I can do all my adjustments with the safety net installed!!

[frackers]

The bottom of the 'boot' has a 80mm hole in it to allow the cables from the mill to emerge. You should be able to see the irrigation pipe anti-sheep cable protector disappearing into the bottom of the pole/boot.

[Ungrounded Lightning Rod]

Sounds even better than what I suggested.

[BigBreaker]

The wood posts seem to be splitting along the grain and might open up over time from force and freeze cycles.  you could drill a small but long hole through each of the posts parallel to the ground but 90 degrees to the pivot pipe and a few inches above it.  I'd put some all thread through that hole and hold the wood together with big washers and hefty nuts.  Alternatively some big pipe clamps or their equivalent?  Maybe the cracking isn't as bad as it looks.

[frackers]

The crack that shows in the first picture (and in the pivot/r-clip picture) only goes as far as the heartwood of the post on the one side. I've got to get some bracing steel strip we use here for earthquake strapping to wrap round it.

Thanks for the reminder though :-)

[Ungrounded Lightning Rod]

It's called "checking" and is a result of drying out too fast.  It's normal for stuff like posts - and log furniture.

Which is not to say don't reinforce it.