2" shaft mounting Pt.62: Drop test!

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As I was loading counterweights onto the mounting the Black and Decker workbench snapped! One of the stand's plywood 'jaws' parted company at the central, drilled holes.

The mounting is now upside down, with the saddle resting on the other B&D workbench. It missed my brand new miter saw by only an inch or two!

It could easily have been much worse because I was standing right behind the workbench to add the 4 x 5kg [45lbs] of weights. So I could easily have been badly injured!

I was going to use the chain hoist to lift the mounting to a more dignified angle but it has chosen this moment to disintegrate! Most of the small nuts have come off unnoticed! With the lift chain now wrapped around its geared shaft. Grrr? 😕

The hoist proved to be completely undamaged but I replaced the plain, cover holding nuts with Nyloc nuts anyway.

The covers are probably more decorative than active. Though the lighter pull chain does pass through slots perhaps to avoid derailing the chain.

The vibration from pulling the chain rapidly through the hoists had loosened the cover holding nuts despite the split spring washers. The mechanism itself is entirely self contained and would probably function well enough without the covers. The very low gearing requires many meters of chain to be pulled through with only a small movement of the heavier lift chain and hook. There is some resistance to a change of direction but it does not seem to be dangerous.

Fortunately I was able to drop the heavy counterweights gently onto stacked pieces of timber packing without any effort. Then release and withdraw the heavy declination shaft clear of its bearings. The chain hoist having been quickly repaired I was then able to lift the mounting onto a low but sturdy support.


I have new respect for the accumulated weight of the mounting and the vulnerability of B&D folding work benches. I shall certainly never use a workbench to stand on ever again. Spreading the load with a sheet of plywood might have helped but the steelwork of the stand is not without its limits. I should really have built a solid work stand out of slotted angle and plywood! It was only the ability to easily fold the B&D benches out of the way when not in use that made me use one in the first place.

At least the nose dive did not damage anything [visible] on the mounting! Are home-made equatorial mountings supposed to be drop tested to gain CE status?

Click on any image for an enlargement.

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