Hofmann Rotary Table Features

[Andy StopfordParticipant @andystopford50521]

I have just acquired a 200mm Hofmann Rotary table and wondered what the hole behind the handwheel is for (at the end of the red line in the photo below). It’s obviously meant to have a bar inserted to turn the collar around the worm shaft, but does anyone know why? 

[John HaineParticipant @johnhaine32865]

May have an eccentric collar allowing the worm to be swung clear of the pinion? The rod will be for leverage. Allows the table to be quickly rotated.

[Andy StopfordParticipant @andystopford50521]

That’s what I thought, but I found a thread on here which suggested that the allen screw on the other side was for swinging the worm clear, though it seems a rather inconvenient arrangement.

[BazyleParticipant @bazyle]

More likely the Allen screw, though not quite sure where ‘the other side’ is, will be for setting the depth of engagement.

[DC31kParticipant @dc31k]

It is not quite clear if that hole rotates as the handle rotates, or is stationary.

What it is joined to and its interaction with other parts of the mechanism might assist in determining its function.

A light dismantling of the table might also show you what it is used for.

[Phil PParticipant @philp]

We have discussed this before.

Hofmann Rotary table owners?

Phil P

[Andy StopfordParticipant @andystopford50521]

@Bazyle, sorry, I should have been clearer, the allen screw is the one circled:

@DC31k, it’s stationary, in the sleeve that encloses the wheel shaft – it doesn’t shift under (gentle) attempts to turn it with a bit of rod. As you say, dismantling might be necessary, though I was hoping to avoid that, since it works really nicely as is, with no perceptible backlash.

It might be that slackening the allen screw allows it to move freely; I’ve ordered an allen key – it’s 4.5mm and despite having dozens of the things, that is, of course, the only size not present.

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