An altitude drive in the making!

7th August 2013

The altitude drive for the Millennium telescope is being built like a fishing reel. Two wires wound around a steel tube will be used to tilt the telescope up and down with precise control from the observing platform. The spool for the drive has been made for us by Dave Rose of Rowan Engineering, who has kindly supplied us with this video of his CNC machine in action.

From our Project Engineer, Andrew Baxter:

"An 110mm diameter steel tube is now to be used, with threads cut for the two wires to sit into. Quite a bit of programming went into working out how to cut a large thread in steel. First the tube had to be machined to make sure it was a true circle.

The thread is cut with a 4 mm dia ball ended cutter, similar to that used by dentists, running at 2750rpm. It required two passes to cut the full depth, and needed constant flooding with coolant. The coolant is not milk, but 99% water with a dash of soluble oil. All the machining operations are controlled by a computer.

A steel shaft will be fitted through the length of the tube, and bearings and gear wheels attached.

The steel channels, angles, plates and framework that the spool fits into are being galvanised. We have the bearings, gears, to fit the lot together, and the electric motor has been finished."