New trapdoor hatch in larch.

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With the realization that I could counterbalance even a heavy hatch I have built a new hatch in larch board. Last time I side hinged the hatch and this was far too clumsy because of the handrails. The leverage was all wrong because of the narrower hatch width. Hopefully a longer lever, from an end hinged hatch, will be easier to handle.

This time I pushed the hinge line well forwards beyond the stepladder's top rung. The outer edges, which fall within the pyramidal pier, will need to be tapered to clear the 4x4s. So I chopped these corners off neatly with the miter saw.

I shall add a toe bumper to the pier end of the hatch. Just in case my feet should accidentally seek out the gap beyond the hatch inside the pier. Very unlikely but it costs practically nothing to fit one. It is just possible that I might slip on the hatch while moving towards the pier. Perhaps if I was coming in from the veranda with snow on my shoes. The bumper should prevent any sudden "rabbit hole" moments. 

The hatch overlaps the pier footprint by several inches. So it should be difficult to find fresh air beneath my feet even in the dark. It is unlikely I'd be standing right next to the pier while using the telescope except while viewing overhead towards the east.

The images show the results of my labours without the hinges being bolted into place. I still need to recess the hinge areas so that they can lie flush. The hatch is much easier to lift from below thanks to the improved leverage. This is despite it being longer and heavier than the last. It was more difficult to struggle up the steps but much easier to work with it once in place.

I shall still have some counterbalancing but wonder whether cables are really necessary. The loads are quite paltry for almost any diameter of stranded steel cable. I can measure the counter-pull required with a spring balance. Then halve the measurement for a weight, cable supported from each side. This will avoid twisting forces on the hatch.

Once I have the hatch hinged properly I can replace the narrower boards each side of the hole in the floor to fill in the gaps.

Friday: More stainless steel bolts and nuts arrived so I could replace the already rusting black bolts for the steering wheel axles. These had plain shanks so were a much better fit for the steering wheels and disks.

Click on any image for an enlargement.

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