It will be a case of all hands to the pump as a Norfolk landmark gets its cap back.
Millwrights working to precise measurements will find out on Tuesday if everything goes back together as hoped at Horsey.
The complex operation involves a 100-tonne capacity crane which will lift the lovingly restored cap back into place - a milestone in an on-going project to bring the roadside windpump back into full working order.
And it will be a nail-biting and slow process for everyone involved, because it could all so easily go wrong.
A perfect fit means the sails can be pinned back later in the year and start turning for the first time since 1943.
Otherwise, it is back to the workshop for adjustments and a second attempt.
Tim Whiting who has been using the tools and techniques that were used to build the mill just over a hundred years ago, said: 'It's going to be a really nervous time lifting the cap.
'The moment it's positioned onto the windpump tower, we'll find out after a year's worth of restoration and careful measuring, whether we got it right.
'In order for the sails to be installed and working later this summer, we need to make sure the cap is able to turn freely; so this is the point where a lot of the hard work comes together.'
Meanwhile the tower has also been repaired to ensure the top is perfectly level and round.
The National Trust's project manager, Paul Coleman, said: 'Over the past year I've seen the cap go from a state of fragility to strength.
'We've made some interesting discoveries along the way, including some wooden components of the caps structure that pre-date the current windpump quite considerably, with the oldest piece thought to date back to the 17th century.
'It would appear that the cap frame had been constructed with wood from possibly three older caps, from other mills.
'I'm proud to have played a part in such a special project that will enable this mighty machine to be given back to the Norfolk landscape.'
The project team will be on hand to chat to visitors during National Mills Weekend this Saturday and Sunday although the mill will be shut.
The tea-room will be open on Tuesday 10am and 4.30pm.
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